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General principles

GENERAL PRINCIPLES TO TAKE INTO ACCOUNT IN THE ASSESSMENT OF OENOLOGICAL PRACTICES AND SUBSTANCES COMPOSINGOENOLOGICAL PRODUCTS

OIV-OENO 602-2022

 

Oenological practices:

-          are safe biological, physical and chemical practices intended for the production and preservation of vitivinicultural products,

-          preserve the natural and essential characteristics and composition of wine,

-          should not cause consumer confusion or facilitate this.

Wherever possible and reasonable, preference should be given to substances that are extracted from grapes/substances of vitivinicultural origin.

Oenological practices and the use of oenological substances should not mask the effects of the use of defective raw materials, faulty raw materials, or unhygienic practices[1].

Taking this into consideration the OIV establishes a specific description of each oenological practice and any use of oenological substances, including its objectives, purposes and conditions of use. Oenological practices and the use of oenological substances recommended and published by OIV shall only be used for the purposes described and, in the manner, described to provide a benchmark for good manufacturing practice.

Oenological practices and oenological substances are used:

-          to prevent or eliminate wine defects (oxidation, bacterial contamination, tartaric precipitation, etc.),

-          to improve the process of winemaking (control the fermentations, improve the filterability, improve clarification,…),

-          to improve the storage capacity or stability of the vitivinicultural product and maintenance of its organoleptic qualities,

-          as additives or processing aids, while the status of the substance depends on their use.

There is a sufficient technological need to justify the use of the oenological substance, or the treatment gives evident advantages, economically or technically, compared to the present practices and consumers are not misled through the use of the oenological treatment agent; the oenological substance provides advantages to consumers and consequently fulfils one or several objectives such as: 

-          preservation of the nutritive quality of the vitivinicultural products,

-          improvement of the storage capacity or stability of the vitivinicultural product and maintenance of its organoleptic qualities.

The OIV establishes a specification for each oenological substance concerning the origin, purity and other necessary indications.

The OIV evaluates and develops new oenological practices or revises those that already exist, also taking into account environmental impact/sustainability according to technological innovations.

The OIV recommends that:

-          the quantity of an oenological treatment agent added in the elaboration of a product shall be limited to the lowest possible level necessary to accomplish its desired effect,

-          the quantity of the oenological treatment agent that as a result of its use transforms to another product not intended to accomplish any physical or other technical effect in the vitivinicultural product itself, is reduced to the extent reasonably possible.

The OIV recommends maximum numerical use levels for oenological substances with an acceptable daily intake (ADI) set by JECFA or other Food Safety Authorities, also taking account of the opinion of the OIV’s “Food Safety” Group. The OIV also recommends numerical limits for best use of the technological function and/or for quality purposes on the basis of experimental data analysed by its own experts.  In the absence of fixed numerical limits from the OIV, the OIV recommends oenological substances shall be used at levels established for GMP, which are the lowest levels possible to provide a specific technological function.


[1] "hygiene", means the measures and conditions necessary to control hazards and to ensure fitness for human consumption of wine, wine-based beverages, table grapes, raisins and other vine-based products taking into account its intended use

Alginic acid

COEI-1-ALGIAC Alginic acid

Sin no. 400

C.A.S. no.: 9005-32-7

  1. Subject, origin and scope

Alginic acid is a colloidal polysaccharide extracted from various varieties of brown algae in particular from Laminaria. The monomers constituting the -L-glucuronic acid and - D-mannuronic acid are bound in pairs as connections of the type 1 4

-[ α-glu-14- α-glu-14- β-man-1- β-man-1- α-glu

A clarifying agent, which, after being neutralized before use by potassium chloride, or potassium carbonate or potassium hydrogenocarbonate can be added to the drawn-off liquid, designed to carry out the second fermentation of sparkling wines (foam formation).

Alginic acid is made up on average of 200 basic units of uronic acids.

Their molecular weight ranges between 10 000 and 600 000 U.

  1. Labeling

The concentration of alginic acid must be indicated on the label, as well as the conditions of safety and conservation.

  1. Characteristics

Alginic acid exists in powder or filament form, or as amorphous granules of a yellowish white to brown color, insoluble in pure water and the various organic solvents. It can dissolve in water alkalized by sodium carbonate, sodium hydroxide or trisodium phosphate.

 

  1. Identifying characteristics

4.1. pH

A suspension of 3% alginic acid in water has a pH ranging between 2 and 3.5.

4.2. Differentiation with other polysaccharides

An alginic acid solution of 5 g/l in sodium hydroxide (dissolve 4.3 g of sodium hydroxide in water and complete to 100 ml) precipitate in gelatinous form by adding a fifth of volume of a 2.5% solution of calcium chloride.

Furthermore, an addition of a half volume of a solution saturated with ammonia sulfate to the solution previously described does not cause any turbidity.

These two tests can be used to differentiate alginic acid from other polysaccharides that may be used in foodstuffs or pharmaceuticals.

4.3. Organoleptic characteristics

Alginic acid must have no taste, or abnormal odor.

  1. Tests

All the limits described below refer to the dry weight of alginic acid.

5.1. Insoluble in a solution of sodium hydroxide

Dissolve by prolonged magnetic agitation 1 g of alginic acid weighed with precision in 100 ml of a solution of sodium hydroxide (dissolve 4.3 g of sodium hydroxide in water and complete to 100 ml), centrifuge, decant, and wash the residue 5 times with distilled water, with centrifugation and drainage of the washwater each time. Transfer all the residue using distilled water to a Gooch filter that has been tared beforehand (filter made of sintered glass of low porosity), dry for 1 hour at 105°C and weigh again.

The rate of insoluble should not exceed 2% in relation to the dry weight of the alginic acid.

5.2. Loss on desiccation

Determine until constant weight, on a test specimen of 2 g, the loss of weight, at 100-105°C, the alginic acid must be lower than 15 p. 100

5.3. Sulfuric ash

Proceed as indicated in chapter II of the international oenological Codex. The sulfuric ash content should not be higher than 8 p 100 in weight of the alginic acid.

5.4. Preparation of the solution for tests

After weighing the ashes, dissolve them in 2 ml of concentrated hydrochloric acid (R) and 10 ml of water. Heat to activate the dissolution and add water until a volume equal to 25 times the weight of the dry alginic acid is obtained. 1 ml of this solution contains the mineral matter of 0.04 g of dry alginic acid.

5.5. Lead

On the solution prepared for tests (5.4), to carry out the dosage of lead according to the method described in chapter II of the international oenological Codex.

The lead content must be lower than 5 mg/kg.

5.6. Cadmium

On the solution prepared for the tests (5.4), determine the cadmium using the method described in chapter II of the international oenological Codex.

The cadmium content must be lower than 1 mg/kg.

5.7. Mercury

Determine the mercury using the method described in Chapter II of the international oenological Codex.

The mercury content must be lower than 1 mg/kg.

5.8. Arsenic

On the solution prepared for the tests (5.4), determine the arsenic using the method described in Chapter II of the international oenological Codex.

The arsenic content must be lower than 3 mg/kg.

5.9. Bacteriological control

Proceed as indicated in chapter II of the international Oenological Codex for each parameter.

Limit: total viable microorganisms: less than 5 x 103 CFU/g.

5.10.      Coliforms

The number of coliforms must be lower than or equal to 1 per g.

5.11.      Staphilococca

The number of staphilococca (-haemolytics with positive coagulase) must be lower than or equal to 1 per g.

5.12.      Salmonella

The number of salmonella must be lower than 1 per 100 g.

5.13.      Yeast

Limit concentration: 5 x 102 CFU per g of preparation.

5.14.      Lactic bacteria

Limit concentration: 102 CFU per g of preparation.

5.15.      Lactobacillus sp.

Limit concentration: 10 CFU per g of preparation.

5.16.      Pediococcus sp.

Limit concentration: absence in a sample of 10 g of preparation.

5.17.      Acetic bacteria

Limit concentration: 103 CFU per g of preparation.

5.18.      Moulds

Limit concentration: 5 x 102 CFU per g of preparation.

  1. Storage

Alginic acid must be kept in sealed bags.

Calcium (Alignate)

SIN N°: 402

  1. Object, origin and scope of application

Calcium alginate is obtained from a 1 % aqueous solution of potassium alginate or alginic acid placed in contact with a 20 % aqueous solution of calcium chloride. Beads of calcium alginate can be produced by dropping droplets of potassium alginate solution into a calcium chloride solution.

Beads of calcium alginate, dry or wet, can contain yeasts or lactic bacteria, dry or wet. They are used for foam forming purposes in the bottle for sparkling wine or to restart alcoholic fermentation in still wines or to start the malolactic fermentation.

These beads can be coated with a double layer of potassium or calcium alginate or with colloidal silica to prevent the precipitation of the yeasts or bacteria incorporated into the beads.

  1. Labelling

The label should indicate the product’s purity and the safety and storage conditions for calcium alginate, the yeasts or bacteria incorporated into the beads, the expiration date and the lot number.

  1. Characteristics

Calcium alginate is a translucent gel, which is insoluble in water and wine. It only dissolves in a sodium metaphosphate solution.

An alginic acid precipitate is also produced if 1 ml of sulfuric acid diluted to 10 % (R) is added to 10 ml of an aqueous 1 % (m/v) suspension of calcium alginate.

Alginic acid

COEI-1-ALGIAC Alginic acid

Sin no. 400

C.A.S. no.: 9005-32-7

  1.      Subject, origin and scope

Alginic acid is a colloidal polysaccharide extracted from various varieties of brown algae in particular from Laminaria. The monomers constituting the -L-glucuronic acid and - D-mannuronic acid are bound in pairs as connections of the type 1 4

-[ α-glu-14- α-glu-14- β-man-1- β-man-1- α-glu

A clarifying agent, which, after being neutralized before use by potassium chloride, or potassium carbonate or potassium hydrogenocarbonate can be added to the drawn-off liquid, designed to carry out the second fermentation of sparkling wines (foam formation).

Alginic acid is made up on average of 200 basic units of uronic acids.

Their molecular weight ranges between 10 000 and 600 000 U.

  1.      Labeling

The concentration of alginic acid must be indicated on the label, as well as the conditions of safety and conservation.

  1.      Characteristics

Alginic acid exists in powder or filament form, or as amorphous granules of a yellowish white to brown color, insoluble in pure water and the various organic solvents. It can dissolve in water alkalized by sodium carbonate, sodium hydroxide or trisodium phosphate.

 

  1.      Identifying characteristics
  1. pH

A suspension of 3% alginic acid in water has a pH ranging between 2 and 3.5.

  1. Differentiation with other polysaccharides

An alginic acid solution of 5 g/l in sodium hydroxide (dissolve 4.3 g of sodium hydroxide in water and complete to 100 ml) precipitate in gelatinous form by adding a fifth of volume of a 2.5% solution of calcium chloride.

Furthermore, an addition of a half volume of a solution saturated with ammonia sulfate to the solution previously described does not cause any turbidity.

These two tests can be used to differentiate alginic acid from other polysaccharides that may be used in foodstuffs or pharmaceuticals.

  1. Organoleptic characteristics

Alginic acid must have no taste, or abnormal odor.

  1.      Tests

All the limits described below refer to the dry weight of alginic acid.

  1. Insoluble in a solution of sodium hydroxide

Dissolve by prolonged magnetic agitation 1 g of alginic acid weighed with precision in 100 ml of a solution of sodium hydroxide (dissolve 4.3 g of sodium hydroxide in water and complete to 100 ml), centrifuge, decant, and wash the residue 5 times with distilled water, with centrifugation and drainage of the washwater each time. Transfer all the residue using distilled water to a Gooch filter that has been tared beforehand (filter made of sintered glass of low porosity), dry for 1 hour at 105°C and weigh again.

The rate of insoluble should not exceed 2% in relation to the dry weight of the alginic acid.

  1. Loss on desiccation

Determine until constant weight, on a test specimen of 2 g, the loss of weight, at 100-105°C, the alginic acid must be lower than 15 p. 100

  1. Sulfuric ash

Proceed as indicated in chapter II of the international oenological Codex. The sulfuric ash content should not be higher than 8 p 100 in weight of the alginic acid.

  1. Preparation of the solution for tests

After weighing the ashes, dissolve them in 2 ml of concentrated hydrochloric acid (R) and 10 ml of water. Heat to activate the dissolution and add water until a volume equal to 25 times the weight of the dry alginic acid is obtained. 1 ml of this solution contains the mineral matter of 0.04 g of dry alginic acid.

  1. Lead

On the solution prepared for tests (5.4), to carry out the dosage of lead according to the method described in chapter II of the international oenological Codex.

The lead content must be lower than 5 mg/kg.

  1. Cadmium

On the solution prepared for the tests (5.4), determine the cadmium using the method described in chapter II of the international oenological Codex.

The cadmium content must be lower than 1 mg/kg.

  1. Mercury

Determine the mercury using the method described in Chapter II of the international oenological Codex.

The mercury content must be lower than 1 mg/kg.

  1. Arsenic

On the solution prepared for the tests (5.4), determine the arsenic using the method described in Chapter II of the international oenological Codex.

The arsenic content must be lower than 3 mg/kg.

  1. Bacteriological control

Proceed as indicated in chapter II of the international Oenological Codex for each parameter.

Limit: total viable microorganisms: less than 5 x 103 CFU/g.

  1.       Coliforms

The number of coliforms must be lower than or equal to 1 per g.

  1.       Staphilococca

The number of staphilococca (-haemolytics with positive coagulase) must be lower than or equal to 1 per g.

  1.       Salmonella

The number of salmonella must be lower than 1 per 100 g.

  1.       Yeast

Limit concentration: 5 x 102 CFU per g of preparation.

  1.       Lactic bacteria

Limit concentration: 102 CFU per g of preparation.

  1.       Lactobacillus sp.

Limit concentration: 10 CFU per g of preparation.

  1.       Pediococcus sp.

Limit concentration: absence in a sample of 10 g of preparation.

  1.       Acetic bacteria

Limit concentration: 103 CFU per g of preparation.

  1.       Moulds

Limit concentration: 5 x 102 CFU per g of preparation.

  1.      Storage

Alginic acid must be kept in sealed bags.

Calcium (Alignate)

SIN N°: 402

  1. Object, origin and scope of application

Calcium alginate is obtained from a 1 % aqueous solution of potassium alginate or alginic acid placed in contact with a 20 % aqueous solution of calcium chloride. Beads of calcium alginate can be produced by dropping droplets of potassium alginate solution into a calcium chloride solution.

Beads of calcium alginate, dry or wet, can contain yeasts or lactic bacteria, dry or wet. They are used for foam forming purposes in the bottle for sparkling wine or to restart alcoholic fermentation in still wines or to start the malolactic fermentation.

These beads can be coated with a double layer of potassium or calcium alginate or with colloidal silica to prevent the precipitation of the yeasts or bacteria incorporated into the beads.

  1. Labelling

The label should indicate the product’s purity and the safety and storage conditions for calcium alginate, the yeasts or bacteria incorporated into the beads, the expiration date and the lot number.

  1. Characteristics

Calcium alginate is a translucent gel, which is insoluble in water and wine. It only dissolves in a sodium metaphosphate solution.

An alginic acid precipitate is also produced if 1 ml of sulfuric acid diluted to 10 % (R) is added to 10 ml of an aqueous 1 % (m/v) suspension of calcium alginate.

Lactic acid

COEI-1-ACILAC L-Lactic acid, D-Lactic acid, D,L-Lactic acid2-hydroxypropanoic acid

N° SIN : 270

C.A.S.  number 50-21-5

(L-: 79-33-4;  D-: 10326-41-7;  DL-: 598-82-3)

chemical formula C3H6O3

Molecular mass: 90.08, density 1.20-1.21.

  1. Object, origin and field of application

 

An acid of natural origin obtained by lactic fermentation of sugars or synthetically made; it may contain condensation products such as lactate from lactic acid and dilactide.

It is used for the acidification of musts and wines in the conditions set by the regulation.

 

  1. Labelling

The label must mention particularly clearly that it concerns L-lactic or D-Lactic acids obtained by fermentation or D,L-Lactic obtained by a chemical process, the storage conditions and expiration date.

The common commercial products are solutions at 50%-90%.

Solid products containing about 100%-125% of titrable lactic acid also exist. (Note: Lactic acid is hygroscopic and once concentrated by boiling or distillation, it forms condensation products that hydrolyse into lactic acid by dilution and by heating in water).

Purity level: not less than 95.0% and not more than 105.0% of the concentration marked.

 

  1. Characteristics

Colourless or slightly yellow and syrupy liquid with a clearly acid flavour to a slightly lactic taste.

  1. Solubility
  • Water at 20°C: very soluble
  • Alcohol at 95% vol.: Very soluble
  • Ether: very soluble
  • Insoluble in chloroform.
  1. Optical rotation

 

For L-lactic acid aqueous solution at 2.5 g for 100 ml.

is 2.6°

For D-lactic acid in aqueous solution at 8 g for 100 ml.

is -2.6°

  1. Identity characters

6.1.         Characterisation of lactic acid

In a 100 ml conical flask, weigh 10 g of lactic acid, add 5 ml of sulphuric acid 0.5 M, shake, add 25 ml of potassium permanganate at 0.33% and place on a hot plate. Collect the vapour released on a filter paper soaked with a solution at 50% vol/vol of morpholine at 20% and potassium nitrocyanoferrate (II) at 5%.

The filter paper becomes blue.

6.2.         Determination of total lactic acid

Titrate the free lactic acid with sodium hydroxide 1 M then hydrolyse the polymerised lactic acid using an excess of sodium hydroxide and then determined by sulphuric acid 0.5 M.

6.3.         Colour

Compare the colour with the standards of the alpha scale (colour standards of platinum-cobalt).

6.4.         Stereochemical purity

The method is based on the separation by HPLC using a chiral phase of two enantiomers of lactic acid. The product is diluted in water beforehand. Enzymatic determinations can also be performed according to the methods in the Compendium of international methods of analysis of wines and musts.

  1. Test trials

 

7.1.         Preparation of the test trial solution

For the purity test trials, prepare a solution containing 10% m/v of lactic acid by using the concentration marked.

7.2.         Sulphuric ashes

From a 2 g sample of lactic acid, determine the sulphuric ashes as indicated in chapter II of the International Oenological Codex.

The content must be less than or equal to 1 g/kg.

7.3.         Chlorides

To 0.5 ml of the test trial solution (7.1), add 14.5 ml of water, 5 ml of diluted nitric acid (R) and 0.5 ml of silver nitrate solution at 5% (R). The solution should satisfy for the test trial, the determination limit of chlorides described in chapter II of the International Oenological Codex.

The chloride content must be less than 1 g/kg expressed in hydrochloric acid.

7.4.         Iron

To 10 ml of the test trial solution (7.1), add 1 ml of concentrated hydrochloric acid (R) and 2 ml of the potassium thiocyanate solution at 5% (R). The red colouration obtained must not be darker than the control prepared with 1 ml of the iron salt solution (III) at 0.010 g of iron per litre (R), 9 ml of water and the same quantities of the same reagents.

The iron content must be less than 10 mg/kg.

Iron can also be determined by atomic absorption spectrometry according to the method described in chapter II of the International Oenological Codex.

7.5.         Lead

Using the test trial solution (7.1), apply the method described in chapter II of the International Oenological Codex.

Lead content should be less than 2 mg/kg.

7.6.         Mercury

Using the test trial solution (7.1), determine the mercury according to the method described in chapter II of the International Oenological Codex.

Mercury content should be less than 1 mg/kg.

7.7.         Cadmium

Using the test trial solution (7.1), determine the cadmium according to the method described in chapter II of the International Oenological Codex.

Cadmium content should be less than 1mg/kg.

7.8.         Arsenic

Using the test trial solution (7.1), determine the arsenic according to the method described in chapter II of the International Oenological Codex.

Arsenic content should be less than 3 mg/kg.

7.9.         Sulphates

To 1 ml of the test trial solution (7.1), add 18 ml of water, 1 ml of diluted hydrochloric acid at 10% (R) and 2 ml of barium chloride solution at 10% (R). The solution should satisfy for the test trial, the determination limit of sulphates described in chapter II of the International Oenological Codex.

Sulphate content should be less than 1 g/kg, expressed in sulphuric acid.

7.10.     Cyanides

In a 40 ml volumetric flask containing 25 ml of distilled water and 2.5 ml of buffer solution at pH 7.5 (R), introduce 0.4 ml of the test trial solution (7.1), add 0.3 ml of chloramine T solution at 0.1% (R). Wait 90 seconds and add 6 ml of pyridine-pyrazolone reagent (R). Complete to 40 ml with distilled water and mix. The colouration obtained must not be darker than that obtained by treating the same way 4 ml of a freshly prepared potassium cyanide solution titrating 1 mg of hydrocyanic acid per litre (R).

Free cyanide content expressed in hydrocyanic acid should be less than 1 mg/kg.

7.11.     Citric acid

To 5 ml of the test trial solution (7.1), add 5 ml of water, 2 ml of mercury sulphate solution (II) (R), bring to the boil and add a few drops to the potassium permanganate solution at 2% (R). No white precipitate should form.

7.12.     Citric, oxalic, tartaric and phosphoric acids

Dilute 1 ml of the test trial solution (7.1) in 10 ml of water, add 40 ml of the calcium hydroxide solution (R) bring to the boil for 2 minutes. No turbidity should form.

7.13.     Sugars

Add 2 ml of the test trial solution (7.1) to 10 ml of cupro-alkaline reagent (R). No red precipitate should form.

  1. Storage

Lactic acid should be stored in hermetically sealed containers away from heat and light.

Malic acid

COEI-1-ACIMAL L-Malic acid , DL-Malic acid

2-hydroxybutanedioic acid

N° SIN: 296

C.A.S.  number 617-48-1

Chemical formula C4H6O5

Molecular mass: 134.09

  1. Object, origin and field of application

 

An acid of natural origin contained in most fruit (L-malic acid) or synthetically made: DL-malic.

It is used for the acidification of musts and wines in the conditions set by the regulation.

 

  1. Labelling

The label must mention particularly clearly that it is L-malic or D,L-malic acid, the storage conditions and date of expiry.

Malic acid content should be at least 99%.

  1. Characteristics

 

White or off-white crystalline powder or granules with a clearly acid flavour.

Melting point of D,L-malic: 127°C-132°C

Melting point of L-malic: 100°C.

  1. Solubility

 

  • Water at 20°C: 55.8 g/100
  • Alcohol at 95% vol.: 45.5 g/100.
  • Ether: 0.84 g/ 100
  1. Optical rotation

 

For the L-Malic acid in aqueous solution at 8.5 g for 100 ml.

is -2.3°

  1. Identity characters

 

6.1. Characterisation of malic acid

Malic acid can be determined by an enzymatic process according to the methods in the Compendium of international methods of analysis of wines and musts (specifically L-malic and D-malic acids. Malic acid can also be determined by HPLC according to the method in the Compendium of international methods of analysis of wines and musts.

  1. Test trials

 

7.1. Preparation of the test trial solution

For purity trials, prepare a solution containing 10% m/v of malic acid.

7.2. Sulphuric cinders

From a 2 g sample of malic acid, determine the sulphuric cinders as indicated in chapter II of the International Oenological Codex.

Content must be less than or equal to 1 g/kg.

7.3. Chlorides

To 0.5 ml of the test trial solution (7.1), add 14.5 ml of water, 5 ml of diluted nitric acid (R) and 0.5 ml of silver nitrate solution at 5% (R). The solution should satisfy for the test trial, the determination limit of chlorides described in chapter II of the International Oenological Codex.

Content must be less than 1 g/kg expressed in hydrochloric acid.

7.4. Iron

To 10 ml of the test trial solution (7.1), add 1 ml of concentrated hydrochloric acid (R) and 2 ml of potassium thiocyanate solution at 5% (R). The red colouration obtained should not be darker than that of the control prepared with 1 ml of an iron salt solution (III) at 0.010 g of iron per litre (R), 9 ml of water and the same quantities of the same reagents.

Content must be less than 10 mg/kg.

Iron can also be determined by atomic absorption spectrometry according to the method described in chapter II of the International Oenological Codex.

7.5. Lead

Using the test trial solution (7.1), apply the method described in chapter II of the International Oenological Codex.

Lead content must be less than 5 mg/kg.

7.6. Mercury

Using the test trial solution (7.1), determine the mercury according to the method described in chapter II of the International Oenological Codex.

Mercury content must be less than 1 mg/kg.

7.7. Cadmium

Using the test trial solution (7.1), determine the cadmium according to the method described in chapter II of the International Oenological Codex.

Cadmium content must be less than 1 mg/kg.

7.8. Arsenic

Using the test trial solution (7.1), determine the arsenic according to the method described in chapter II of the International Oenological Codex.

Arsenic content must be less than 3 mg/kg.

7.9. Sulphates

To 1 ml of the test trial solution (7.1), add 18 ml of water, 1 ml of diluted hydrochloric acid at 10% (R) and 2 ml of the barium chloride solution at 10% (R). The solution should satisfy for the test trial, the determination limit of sulphates described in chapter II of the International Oenological Codex.

Sulphates content must be less than 1 g/kg, expressed in sulphuric acid.

7.10.       Cyanides

In a 40 ml volumetric flask containing 25 ml of distilled water and 2.5 ml of buffer solution at pH 7.5 (R), introduce 0.4 ml of the test trial solution (7.1), add 0.3 ml of chloramine T solution at 0.1% (R). Wait 90 seconds and add 6 ml of pyridine-pyrazolone reagent (R). Complete to 40 ml with distilled water and mix. The colouration obtained must not be darker than that obtained by treating the same way 4 ml of a freshly prepared potassium cyanide solution titrating 1 mg of hydrocyanic acid per litre (R).

Free cyanide content expressed in hydrocyanic acid must be less than 1 mg/kg.

7.11.                                                                                                                                                                                                                                                                    Sugars

Add 2 ml of the test trial solution (7.1) to 10 ml of cupro-alkaline reagent (R). No red precipitate should form.

7.12.                                                                                                                                                                                                                                                                    Fumaric and maleic acids

Limit in fumaric acid: 1% in weight.

Limit in maleic acid: 0.05% in weight. These acids are determined by HPLC according to the method described in the Method of Analysis of Wines and Musts in the same way as malic and tartaric acids.

  1. Storage

 

Malic acid should be stored in hermetically sealed containers away from heat and light.

Rectified alcohol of agricultural origin

COEI-1-ALCAGR Rectified alcohol of agricultural origin

  1. Objective, Origin and Scope of Application

Rectified, or "neutral," alcohol obtained by distilling and rectifying alcohol from wine, wine sediments or alcoholic fermentation products derived from from grape or raisin marcs, and all other plant-based substances of agricultural origin.

Rectified alcohol of agricultural origin forms an ingredient of some spirits and special wines.

  1. Composition

At a temperature of 20 °C, 100 parts of this alcohol contain at least 96 parts ethanol.

Note: The tests and controls described below in italics are not mandatory and are performed only upon request.

  1. Properties

 

Colorless, clear, volatile liquid with a penetrating odor and fiery flavor. It is flammable and burns without smoke and with a blue flame.

It should be distilled completely at between 78 and 79 °C.

3.1.    Solubility

Neutral alcohol is miscible in water in all proportions with a notable release of heat and contraction of volume. It is also mixable with in acetone, chloroform, ethyl ether, glycerol, and an equal volume of castor oil.

3.2.    Characterization Procedure

  • Slowly heat a mixture of 1 ml neutral alcohol, twenty drops of concentrated sulfuric acid (R) and 10 g of sodium acetate (R) in a test tube.  A strong, characteristic odor of ethyl acetate will be released.
  • Mix several drops of alcohol and 1 ml of concentrated sulfuric acid (R), then add several drops of 10 pp 100  potassium dichromate solution.  The liquid will become green and emit the odor of ethanal.
  • Dilute 0.5 ml of alcohol with 4.5 ml of water. Add 1 ml of 1M sodium hydroxide solution, then slowly add 2 ml of iodized potassium iodide (R). An odor of iodoform will be produced, following by the formation of a yellow precipitate.
    1.     Analysis of Agricultural Origin

This analysis is carried out by measuring the ethanol 14C/12C ratio (scintillation) in accordance with the method described in the Spirits Compendium.

  1. Tests

4.1.    Appearance

Take two identical test tubes made of alkali-lime glass about 250 mm high, fill one with alcohol, the other with water, which will serve as a control. Examine the liquids along the cylinder's axis. The alcohol should not exhibit any noticeable coloration.

In one test tube about 250 mm high and 25 mm in diameter, pour 40 ml of alcohol, then dilute it with 80 ml of water. The mixture should not cloud nor present any odor or foreign taste.

4.2.    Foreign Odoriferous Substances

Let 10 ml of alcohol evaporate spontaneously on a strip of white filter paper. No foreign odor should be perceived during or after evaporation.

4.3.    Dry Extract or Non-Volatile Residue

In a 25 ml calibrated dish, heat to 100 °C in a water bath, then slowly evaporate 100 ml of alcohol.  Weigh.  The dry extract should be less than 1.5 g/hl 100% ethanol by volume.

4.4.    Heavy Metals

Take up, using 10 ml dilute chlorhydric acid (R), any residue left from the evaporation of 100 ml alcohol during the dry extract analysis. After heating for several minutes in a 100 °C water bath to stimulate dissolution of this residue, decant the acid solution in a 25 ml volumetric flask after the calibrated dish has been washed three times with 5 ml of water and the volume raised to 25 ml.  Take a 5 ml sample of this solution in a test tube.  Add 2 ml of a pH 3.5 (R) buffer solution, 7.5 ml of water and 1.2 ml of thioacetamide reagent (R). The solution should not produce any white or black precipitates nor any brown or other coloration. At the very least, any coloration produced should be no more intense than that obtained using the general method. (Heavy metal conent expressed in lead, after 50% concentration of the alcohol, should be 0.5 mg/l).

4.5.    Lead

Using the method set forth in the Compendium, perform the lead analysis lead in the solution obtained in the previous paragraph. (Lead content should be less than 0.5 mg/l).

4.6.    Mercury

Using the method described in the annex, carry out the mercury analysis in the solution obtained in Paragraph

(Mercury content should be less than 0.2 mg/l).

4.7.    Arsenic

Using the method described in the annex, carry ou the arsenic analysis in the solution obtained in Paragraph 4.4. (Arsenic content should be less than 0.5 mg/kg after 50% alcohol concentration).

4.8.    Ketones, propan-2-ol and 2-methylpropan-1-ol

Add 3 ml of water and 10 ml of mercury sulfate (II) solution (R) to 1 ml of alcohol, then heat in a 100 °C water bath.  No precipitate should form in the first three minutes.

4.9.    Permanganate Decolorization Time (Barbet Test)

Pour 50 ml of the alcohol sample into a flask. Add 2 ml of freshly prepared potassium permanganate solution to 0.20 g/l (R). Place the container in a 15 °C water bath and start a stopwatch.  Avoid directly exposing the sample to natural or artificial light during the test.

Simultaneously, place 50 ml of the comparison solution in the 15 °C water bath.  This solution is obtained by mixing 3 ml of 5 pp 100 cobalt chloride solution (R), 4.2 ml of 4 pp 100 uranyl nitrate solution (R) and filling to 50 ml with distilled water. Compare the test color to the standard.  Stop the timer when the colors are identical.  Note the amount of time elapsed.  The decolorization time of the permanganate should be at least 20 minutes.

4.10. Sulfured Derivatives

Add approximately 1 ml of mercury, then 20 ml of alcohol to a test tube.  Agitate for 1-2 minutes.  The surface of the mercury should remain brilliant with no black clouding.

4.11. Methanol

4.11.1.     Colorimetric Analysis

Standard solution: weigh 5 g of methanol in a 50 ml volumetric flask, then top off to the line with ethanol (free of methanol).

In a 1-liter volumetric flask, place 1 g of the preceding solution (i.e., 1.25 ml) containing 125 mg of methanol, 250 ml of pure alcohol (methanol free).  Top off with water to 1000 ml.

Test technique: place 1250/A ml of alcohol in a volumetric flask (A is the alcoholmetric titer of the alcohol to be tested.) and fill to the gauge line with water. Place 1 ml of alcohol, diluted to 25 pp 100 in a test tube. Add four drops of 50 pp 100 (m/m) phosphoric acid (R), four drops of 5 pp 100 (m/m) potassium permanganate solution (R), then stir and let sit 10 minutes.  Decolorize the permanganate with several (typically 8) drops of 2 pp 100 (m/v) of potassium anhydrous sulfite (metabisulfite) (R), avoiding any excess.  Add 5 ml of chromotropic sulfuric acid solution (R).  Place in a 70 °C water bath for 20 minutes.  No violet color should appear, or in the event it does appear, it should not be more intense than that of a control prepared using the same technique and the same reagents, with 1 ml of the aforementioned standard solution (maximum methanol content is 50 g/hl at 100% vol.).

4.11.2.     Gas phase chromatography Analysis

  • Equipment (example):
  • Gas phase chromatograph with a flame ionization detector
  • Semi-polar capillary columns, for example Carbowax 20 M .

Test technique:

Prepare a water-alcohol solution using 1 g per liter of the internal standard (4-methylpentane-2-ol) in 50 pp 100 alcohol by volume.

Prepare the solution to be analyzed by adding 5 ml of this solution to 50 ml of alcohol reduced to 50 pp 100 by volume.

Prepare a reference solution of methanol at 100 mg per liter of alcohol at 50 pp 100 by volume.  Add 5 ml of the internal standard solution to 50 ml of this solution.

Inject 2 microliters of the solution to be analyzed added to the internal standard solution, into the chromatograph.

The oven temperature should be 90 °C and the supporting gas flow rate should be 25 ml per minute.  These settings are given as an example.

  • S: surface of the methanol peak of the reference solution
  • : surface of the methanol peak of the solution to be analyzed
  • i: surface of the internal standard solution peak in the solution to be analyzed
  • I: surface of the internal standard solution peak in the reference solution

The methanol content, expressed in milligrams per liter of alcohol at 50 pp 100 by volume, is given by the formula:

The content in grams per hectoliter of pure alcohol is 0.20C (maximum content in methanol 50 g/hl of ethanol at 100% by volume).

4.12. Ammonium Hydroxide and Nitrogenous Bases

Pour 50 ml of the alcohol to be examined into a 200 ml flask.  Add 40 ml of water and two drops of phosphoric acid (ρ 20 = 1.58). Distill and collect the 80 ml that are returned.  Add 2 ml of 10 pp 100 sodium hydroxide ® to the cooled residue. Distill again and collect approximately 7 ml of distillate in a test tube to which had previously been added 2 ml of water and one drop of methyl red solution ®.  The distillate should be drawn to the bottom of the tube using a slender tube.  Titrate using a solution of 0.01 M hydrochloric acid until the indicator turns to red. Let n be the number of milliliters of 0.01 M hydrochloric acid solution used.

1 ml of 0.01 M hydrochloric acid solution corresponds to 0.00014 g of nitrogen (ammoniacal or volatile nitrogen bases).

The quantity of ammoniacal nitrogen or nitrogenous bases expressed in milligrams of nitrogen per liter of ethanol is:

280n/A

Where A is the alcohometric titer by volume of the alcohol studied.

Neutral alcohol should not contain more than 1 mg of nitrogen (ammoniacal or of volatile nitrogenous bases) per liter of ethanol.

(Maximum ammonium hydroxide and nitrogenous base content is expressed in terms of nitrogen is 0.1 g/hl of ethanol at 100% by volume).

4.13. Acidity

Place 100 ml strengthened of 50 pp 100 by volume alcohol in a 250 ml conical flask. Add one drop of phenol red solution (R) and add 0.01 M sodium hydroxide, one drop at a time, until red, where n is the number of milliliters used.

1 ml of 0.01 M sodium hydroxide corresponds to 0.0006 g of acetic acid.

Acidity expressed in milligrams of acetic acid per liter of ethanol is equal to 12n.

This acidity should be less than 15 mg/l of ethanol (or 1.5 g/hl) at the time the alcohol is delivered.

(Maximum acidity expressed in terms of acetic acid is 1.5 g/hl of ethanol at 100% by volume).

Note: Indicator movement should be stable and clear cut during quantitative analysis of the acidity.  If it is not, and especially if the acidity exceeds 15 mg/l, a new test should be conducted after the sample is degassed using the following technique.

100 ml of alcohol at 50 pp 100 by volume is placed in a 250 ml flask whose stopper has two tubes through it.

One tube permits the flask to be kept under a vacuum using a glass filter pump.  Pressure is kept between 55 and 65 cm of mercury.

During the procedure, the other tube allows air bubbling from which carbon dioxide is removed by using a sode wash bottle. To accomplish this, the tube has a capillary portion which is submerged in the alcohol. The rate of air flow through the wash bottle is approximately 1 ml per second.

The procedure should last between 3 and five minutes. Titration is accomplished in the same flask.

4.14. Esters

Add 10 ml of 0.1 M sodium hydroxide solution measured with precision to the solution prepared to analyze acidity as detailed under 4.13 (or 100 ml of alcohol at 50% by volume). Cork the flask and stir while maintaining a temperature equal to or slightly higher than 20 °C. After 24 hours of contact, titrate the excess sodium hydroxide using a 0.1 M solution of hydrochloric acid, where n is the number of milliliters used.

To determine the quantity of 0.1 M hydrochloric acid solution which will neutralize 10 ml of 0.1 M sodium hydroxide solution in the presence of the same quantity of alcohol and of the same indicator movement obtained by decreased pH intervals, perform the following test: place 100 ml of degasified 50 pp 100 alcohol in a 250 ml conical flask.  Add one drop of phenol red solution (R) and n milliliters of 0.1 M sodium hydroxide. Which cuase the indicator to turn to red. Add 10 ml of the 0.1 M sodium hydroxide solution, and, immediately thereafter, add 0.1 M hydrochloric acid solution to obtain the same movement of the indicator, that is, nnof the volume used.

1 ml of 0.1 M sodium hydroxide solution corresponds to 0.0088 g of ethyl acetate.  The ester concentration, expressed in milligrams of ethyl acetate contained in 1 liter of ethanol is:

This content level should not exceed 13 mg for 1 liter of ethanol (or 1.3 g/hl) at the time the alcohol is delivered.

(Maximum ester content expressed in terms of ethyl acetate is 1.3 g/hl of ethanol at 100% of volume).

4.15. Aldehydes

Standard solution: Place 268.3 mg of pure acetal (boiling point: 102°C) in a 100 ml volumetric flask.  Top off to the line with 50 pp 100 alcohol by volume, free of aldehydes.

Dilute this solution to 1/10 in 50 pp 100 alcohol by volume, is free of aldehydes.  The solution obtained contains 100 mg of ethanal per liter of 50 pp 100 alcohol by volume, or 20 g in 100 liters of ethanol.

Test procedure: Place 10 ml of alcohol reduced to 50 pp 100 by volume in a test tube. In a second test tube, place 5 ml of the solution containing 100 mg of ethanal per liter of alcohol at 50 pp 100 and 5 ml of alcohol at 50 pp 100 by volume which is free of aldehydes.  Add to the two tubes 4 ml aniline red chlorhydrate solution decolorized by sulfuric acid (R), stir, and compare the colorations obtained after 20 minutes.

The alcohol to be tested should have a color approximately equal to that of the standard solution.

(Maximum aldehyde content expressed in ethanal is 0.5 g/hl at 100% of volume).

Note concerning 50 pp 100 alcohol by volume without aldehydes: Place 100 ml of alcohol diluted to 50 pp 100 by volume in a 250 ml flask with 2 g of metaphenylene diamine (R) and two pieces of pumice stone.  Connect the flask to a reflux condenser and maintain a gentle boil for one hour.  After cooling, connect the flask to the distilling apparatus and slowly distill without overheating the walls.  Collect 75 ml of distillate in a 100 ml volumetric flask.  Fill to the line with distilled water.

4.16. Superior Alcohols

Propan-1-ol, 2-methylpropan-1-ol, 2- and 3-methylbutan-1-ol.

Quantitative analysis by gas phase chromatography (see methanol).

Maximum content for the sum of each of the alcohols: 0.5 g/hl of ethanol at 100% of volume.

4.17. Furfural

Place 10 ml of alcohol reduced to 50% by volume in a test tube with an emery stopper.  Add 0.5 ml of aniline (R) and 2 ml of crystallizable acetic acid (R).  Stir.  No salmon pink coloration should be perceptible after 20 minutes.

  1. Storage

The alcohol should be stored in inert containers which will not give off metals, ions or plastic constituents.

The containers, as well as storage methods,must be in compliance with safety standards.

Rectified alcohol of viti-vinicultural origin

COEI-1-ALCVIT Rectified alcohol of viti-vinicultural origin

  1. Objective, Origin and Scope of Application

Alcohol obtained exclusively by distillation and rectification from wine, grape marcs, wine sediments, or fermented raisins.

Rectified alcohol of viti-vinicultural origin constitues a constituent of some spirits and special wines.

  1. Composition

At a temperature of 20 °C, 100 parts of this alcohol contain at least 96 parts ethanol.

Note: The tests and controls described below in italics are not mandatory and are performed only upon request.

  1. Properties

Colorless, clear, volatile liquid with a penetrating odor and fiery taste.  It is flammable and burns without smoke and with a blue flame.

It should be distilled completely at between 78 and 79 °C.

3.1.    Solubility

Neutral alcohol is miscible in water in all proportions with a notable release of heat and contraction of volume. It is also mixable with in acetone, chloroform, ethyl ether, glycerol, and an equal volume of castor oil.

3.2.    Characterization Procedure

  • Slowly heat a mixture of 1 ml neutral alcohol, twenty drops of concentrated sulfuric acid (R) and 10 g of sodium acetate (R) in a test tube.  A strong, characteristic odor of ethyl acetate will be released.
  • Mix several drops of alcohol and 1 ml of concentrated sulfuric acid (R), then add several drops of 10 pp 100 potassium dichromate solution.  The liquid will become green and emit the odor of ethanal.
  • Dilute 0.5 ml of alcohol with 4.5 ml of water. Add 1 ml of 1M sodium hydroxide solution, then slowly add 2 ml of iodized potassium iodide (R). An odor of iodoform will be produced, following by the formation of a yellow precipitate.

3.3.    Determination of Viti-vinicultural Origin

This analysis is carried out by measuring the ethanol 14C/12C ratio (scintillation) in accordance with the method described in the Spirits Compendium.

3.4.    If necessary, the viti-vinicultural source of the alcohol can be determined using isotopic methods detailed in the Compendium of Wine and Must Analysis Methods.

  1. Tests

Test are identical to those for rectified alcohol of agricultural origin , but with the following content limits:

4.1.    Methanol

Maximum content 50 g/hl of ethanol at 100% by volume.

4.2.    Acidity

Maximum acetic acid content 1.5 g/hl of ethanol at 100% by volume.

4.3.    Esters

Maximum content of ethyl acetate 1.3 g/hl of ethanol at 100% by volume (or 5 g/hl).

4.4.    Aldehydes

Maximum ethanal content 0.5 g/hl of ethanol at 100% by volume.

4.5.    Superior Alcohols

Maximum content 0.5 g/hl of ethanol at 100% by volume.

4.6.    Preparing the solution for tests

Using 10 ml of dilute hydrochloric acid (R), take up the residue left by evaporating 100 ml of alcohol during the dry extract analysis.  After heating for several minutes in a 100 °C water bath to stimulate dissolution of this residue, decant the acid solution in a 25 ml volumetric flask, and wash the dish three times with 5 ml of water and filled to 25 ml.

4.7.    Heavy metals

Place 5 ml of the prepared solution in a test tube in accordance with paragraph 4.6. Add 2 ml of pH 3.5 (R) buffer solution, 7.5 ml of water and 1.2 ml of thioacetamide reagent (R). The solution should not yield any white or black precipitate nor any brown or coloring.  At the very least, any coloring produced should be no more intense than that obtained using the general method (heavy metals content expressed in terms of lead, after 50% concentration of the alcohol, should be 0.5 mg/l).

4.8.    Lead

Using the method set forth in the Compendium, conduct the quantitative lead analysis on the solution prepared for testing (under paragraph 4.6) (lead content should be less than 0.5 mg/l).

4.9.    Mercury

Carry out the quantitative mercury analysis on the solution prepared for testing (under Paragraph 4.6), implementing the technique described in the annex (mercury content should be less than 0.2 mg/l).

4.10. Arsenic

Conduct the quantitative arsenic analysis on the solution prepared for testing (Paragraph 4.6), using the method described in the annex (Arsenic content should be less than 0.5 mg/kg).

  1. Storage

 

Alcohol should be stored in inert containers which will not give off metals, ions or plastics constituents.

The containers as well as the storage methods must comply with safety standards.

Ammonium chloride

COEI-1-AMMCHL Ammonium chloride

Ammonia Hydrochloride

Ammonii Chloridum

NCl=53.50

SIN NO.: 510

  1. Objective, Origin and Domain of Application

This product is used as a fermentation activator and is reserved for fermentation operations.  It makes available ammonium ions which can be directly assimilated by the yeast.

Statutory limits regulate the amount of ammonium added.

  1. Labeling

The concentration of this product should be indicated on the label, including cases in which it is mixed. In addition, safety and storage conditions should be stipulated.

  1. Centesimal Composition

Cl

66.22

NH3

31.78

  1. Properties

Colorless, odorless crystals with a fresh, salty and piquant taste.  It sublimes without decomposing and is stable in air.

  1. Solubility

Water at 20 °C

350.8 g/l

Water at 100 °C

758 g/l

Alcohol, 95% by vol.

13.3 g/l

  1. Identifying Characteristics

Aqueous solutions of ammonium chloride produce reactions of ammonium and those of chloride.

  1. Testing

7.1.    Sulfur Ash

When quantitifed as indicated in the Annex, the sulfur ash content of the ammonium chloride should not be greater than 0.2 per 100.

7.2.    Preparing the solution for tests

Prepare an aqueous solution from NH4Cl crystals at 10 per 100 (m/v).

7.3.    Sulfates

To 1 ml of solution prepared for tests under paragraph 7.2, add 2 ml of hydrochloric acid diluted to 10 pp 100 (m/v) (R), 17 ml of water and 2 ml of barium chloride solution (R).  The mixture should be clear, or else the opalescence observed after 15 minutes should be less than that of the control solution prepared as indicated in the Annex.  (Sulfate content expressed in terms of sulfuric acid should be less than 1 g/kg).

7.4.    Nitrates

Mix 5 ml of concentrated sulfuric acid (R) and 0.5 ml of an extemporaneously prepared iron (II) sulfate solution at 5 pp 100 in a test tube.  Without mixing, pour 5 ml of the solution prepared under paragraph 7.2.  No coloration should be observed at the surface line separating the two solutions.

7.5.    Phosphates

To 0.5 ml of the solution prepared for testing under Paragraph 7.2, add 5 ml of water and 10 ml of nitro-vanadomolybdic (R) reagent.  Leave in contact for 15 minutes at 20 °C.  If a yellow coloration appears, it should be less intense than that obtained by adding 0.5 ml of a solution of 0.05 g of phosphorous per liter (R), 5 ml of water and 10 ml of nitro-vanadomolybdic (R) reagent. (Phosphate content expressed in terms of phosphorous less than 500 mg/kg).

7.6.    Iron

To 5 ml of solution prepared under paragraph 7.2, add 1 ml of concentrated hydrochloric acid (R), one drop of 2 pp 100 potassium permanganate and 2 ml of 5 pp 100 potassium thiocyanate (R).

If a red coloration appears, it should be less intense than that of a control prepared with 2.5 ml of an iron (III) solution containing 0.01 g of iron per liter (R), 2.5 ml of water and the same quantities of the same reagents. (Iron content should be less than 50 mg/kg).

The iron may also be quantitatively analyzed using atomic absorption spectometry, in accordance with the method detailed in the Compendium.

7.7.    Arsenic

Using the method indicated in the annex, test for arsenic in the test solution prepared in accordance with Paragraph 7.2.  (Arsenic content should be less than 3 mg/kg.)

7.8.    Lead

Using the method described in the Compendium, quantify the lead in the solution obtained under Paragraph 7.2.  (Lead content should be less than 2 mg/kg.)

7.9.    Mercury

Using the method described in the annex, test for mercury in the solution prepared for testing under §7.2. (Mercury content should be less than 1 mg/kg.

7.10. Quantitative Ammonia Analysis

Dilute the solution prepared for testing under paragraph 7.2 to one-tenth strength, then place 10 ml of this dilute solution (i.e., 0.1 g of ammonium chloride) in a steam distillation device.  Add 10 ml of 30% sodium hydroxide (R) and distill 100 ml.  Quantify the distilled ammonia using 0.1 M hydrochloric acid.  Let n be the number of milliliters used:

100 g of ammonium chloride contains 1.7 n g of ammonia (NH3).

(Ammonia content greater than 31.5 pp 100).

7.11. Quantitative Hydrochloric Acid Analysis

Take a 10 ml sample of the solution prepared for testing under paragraph 7.2, which has been diluted to one-tenth strength. Place the sample in a cylindrical flask.  Add 20 ml of 0.1 M silver nitrate solution, 1 ml of concentrated nitric acid (R), 5 ml of iron (III) sulfate solution and 10 pp 100 of ammonium (R). Titrate the excess silver nitrate with a 0.1 M potassium thiocyanate solution. Let n be the number of milliliters used:

100 g of ammonium chloride contains 3.65 (20-n) g of hydrochloric acid (HCl).  (Hydrochloric acid content greater than 67.5 pp 100).

  1. Storage

Ammonium chloride must be stored in water-tight containers away from heat.

Ammonium hydrogen sulfite

COEI-1-AMMHYD Ammonium hydrogen sulfite

Ammonium bisulfite

NH4HSO3 = 99.07

  1. Objective, origin and scope of application

This product falls in the category of preservatives and is used exclusively for fermentation operations. It makes available sulfur dioxide and ammonium ions, which can be directly assimilated by the yeast. There are regulatory restrictions on the amount of ammonium that can be added and on sulfur dioxide content.

  1. Labeling

The concentration of this product, as well as the safety and storage conditions, should be indicated on the label.

  1. Centesimal composition

 

NH3

17.16

SO2

64.67

 

  1. Properties

Ammonium hydrogen sulfite always takes an aqueous solution form. This solution emits a piquant sulfur dioxide odor.

 

  1. Solubility

 

Water at 60 °C

847 g/l

Alcohol, 95% by vol.

Slightly soluble

  1. Identifying characteristics

Aqueous solutions of ammonium hydrogen sulfite produce reactions of ammonium (release of ammonia in the presence of sodium hydroxide when heated) and sulfur dioxide (filter paper soaked in potassium iodate and starch turns blue).

  1. Tests

 

7.1.     Sulfur Ash

As quantified as indicated in the Annex, the proportion of ammonium hydrogen sulfite ash should not be greater than 0.2 per 100.

7.2.     Preparing the Solution for Tests

Prepare a 10 pp 100 (m/v) solution.

 

7.3.     Iron

To 5 ml of the solution prepared for testing under paragraph 2, add 1 ml of concentrated hydrochloric acid (R), one drop of 2 pp 100 potassium permanganate (R) and 2 ml of 5 pp 100 potassium thiocyanate (R).

If a red colorating appears, it should be less intense than that of a control prepared with 2.5 ml of an iron (III) solution of 0.01 g of iron per liter (R), 2.5 ml of water and the same quantities of the same reagents.

(Iron content should be less than 50 mg/kg).

The iron may also be quantified by means of atomic absorption spectrometry, using the technique described in the Compendium.

7.4.     Lead

Use the method detailed in the Compendium on the solution in a concentration of 10 pp 100 prepared for testing (under 7.2) and diluted to one one-twentieth.

7.5.     Mercury

Test for mercury in the solution prepared for testing (under 7.2) using the technique detailed in the annex. (Mercury content should be less than 1 mg/kg.)

 

7.6.     Arsenic

Using the method indicated in the Annex, test for arsenic in 2 ml of the test solution prepared for testing in accordance with paragraph 7.2.  (Arsenic content should be less than 3 mg/kg).

7.7.     Quantitative Ammonia Analysis

Dilute the solution prepared for testing under paragraph 7.2 to one-tenth strength, then place 10 ml of this dilute solution (0.10 g of ammonium hydrogen sulfite) in a steam distillation device (described in the annex).  Add 10 ml of 30 pp 100 sodium hydroxide (R) and distill 100 ml. Quantify the distilled ammonia using 0.1 M hydrochloric acid. Let n be the number of milliliters used:

100 g of ammonium hydrogen sulfite contain 1.7 n g of ammonia (NH3).  Ammonia content should be greater than 16.5 pp 100 (m/m).

7.8.     Quantitative Sulfur Dioxide Analysis

In a 200 ml conical flask, place 50 ml of cold water, then 5 ml of the freshly prepared ammonium hydrogen sulfite solution.  Titrate with 0.05 M iodine in the presence of starch.  Let n be the volume of iodine used.

SO2 content per 100 g: 6.4n

Ammonium hydrogen sulfite should contain at least 62 pp 100 SO2.

  1. Storage

 

Ammonium hydrogen sulfite solutions should be stored in hermetically sealed containers away from heat and cold.

Diammonium hydrogen phosphate

COEI-1-PHODIA Diammonium hydrogen phosphate

Ammonium hydrogen phosphate

Ammonii phosphas

SIN N°.342

  1. Objective, Origin and Scope of Application

This product is used as a fermentation activator and is reserved for fermentation operations.  It makes available ammonium ions, which can be directly assimilated by the yeast. Excess phosphates can lead to iron breakdown.

Statutory provisions limit the amount of ammonium that can be added.

  1. Labelling

The concentration of this product should be indicated on the label, including cases of mixtures. In addition, safety and storage conditions should also be stipulated.

  1. Centesimal Composition

 

H3PO4

74.21

P2O5

53.75

NH3

25.79

  1. Properties

Colorless, monoclinic crystals.  This salt slowly loses small quantities of ammonia in air.

  1. Solubility

Water at 20 °C

689 g/l

Water at 100 °C

1060 g/l

Alcohol, 95% by vol.

insoluble

  1. Identifying Characteristics

6.1.    Prepare a 1 pp 100 (m/v) solution in water.  The solution has a pH of approximately 8, and a slight pink color is produced with several drops of phenolphthalein (R). At 25 °C, the pH of this solution should be between 7.8 and 8.4.

6.2.    This solution produces a yellow precipitate with a nitro-molybdic reagent (R).

6.3.    When heated with several drops of 30% sodium hydroxide solution (R), this solution releases ammonia.

  1. Tests

7.1.    Sulfur Ash

Quantified as indicated in the Annex, the proportion of diammonium phosphate ash should not be greater than 5 g/kg.

7.2.    Preparing the solution for tests

Prepare a 10 pp 100 (m/v) solution.

7.3.    Chlorides

To 0.5 ml of the solution prepared for testing under Paragraph 7.2, add 14.5 ml of water, 5 ml of nitric acid diluted to 10 pp 100 (R) and 0.5 ml of 5 pp 100 silver nitrate solution (R).  After 15 minutes at rest in the dark, there should be no clouding, or any clouding visible should be less intense than that observed in the control prepared as detailed in the annex.  (Hydrochloric acid content is less than 1 g/kg).

7.4.    Sulfates

To 1 ml of solution prepared for tests under paragraph 7.2, add 2 ml of dilute hydrochloric acid (R), 17 ml of water and 2 ml of barium chloride solution (R).  The mixture must not form any precipitate or any opalescence; or else, any opalescence that does occur should be less intense than that observed in the control prepared as indicated in the Annex.  (Sulfuric acid content should be less than 1 g/kg).

7.5.    Oxalic acid

To 5 ml of solution prepared for tests under paragraph 7.2, add 20 drops of acetic acid (R) and 5 ml of solution saturated with calcium sulfate (R). The solution should remain clear.

7.6.    Iron

To the 5 ml of solution prepared under paragraph 2, add 1 ml of concentrated hydrochloric acid (R) and 1 ml of 5 pp 100 potassium thiocyanate solution (R).

Coloring should be less intense than that of a control prepared with 2.5 ml of an iron solution in a concentration of 10 mg of iron per liter (R), 2.5 ml of water and the same quantities of the same reagents. (Iron content should be less than 50 mg/kg.)

Iron may also be analytically quantified by atomic absorption spectometry, according to the method specified in the Compendium.

7.7.    Lead

By implementing the method detailed in the Compendium, carry out quantitative analysis of the solution prepared for testing according to Paragraph 7.2.   (Lead content should be less than 5 mg/kg).

7.8.    Mercury

Test for mercury in the solution prepared for testing (Par. 7.2), in accordance with the method detailed in the Compendium. (Mercury content should be less than 1 mg/kg.)

7.9.    Arsenic

Using the method indicated in the Annex, test for arsenic in 2 ml of the test solution prepared in accordance with paragraph 7.2.  (Arsenic content should be less than 3 mg/kg.)

7.10. Quantitative Ammonia Analysis

Dilute the solution prepared under Paragraph 7.2 to one-tenth strength, then place 10 ml of this dilute solution (0.10 g of ammonium phosphate) in a steam distillation device (described in the Annex).  Add 10 ml of water, 10 ml of 30% sodium hydroxide (R) and distill 10 ml.  Analytically quantify the distilled ammonia using 0.1 M hydrochloric acid.  Let n be the number of milliliters used:

100 g of ammonium phosphate contains 1.7 n g of ammonia (NH3). (Minimum content is 25 pp 100).

7.11. Quantitative Analysis of Phosphoric Acid

Place 25 ml of the solution prepared under paragraph 7.2 in a conical flask.  Add 5 drops of phenolphthalein (R).  The solution should have a pale pink color. If not, add just enough 0.1 M sodium hydroxide solution to cause incipient movement of the indicator. Add 10 drops of bromocresol green (R) and use a burette to pour 0.5 M sulfuric acid until the indicator turns green.

Let n be the volume in ml used:

One liter of 0.5 M solution corresponds to 71 g of phosphoric anhydride or 98 g of phosphoric acid.

Proportion of ammonium phosphate in g per 100 g:

in phosphoric anhydride

2.84 n

in phosphoric acid

3.92 n

The proportion of phosphoric anhydride must range between 51.6 and 55 pp 100, or between 71.5 and 76 pp 100 of phosphoric acid.

  1. Storage

Ammonium phosphate must be stored away from moisture and heat, and in hermetically sealed containers.

Ammonium sulfate

COEI-1-AMMSUL Ammonium sulfate

Ammonium sulfuricum

(NH4)2SO4 = 132.10

SIN NO. 517

  1. Objective, Origin and Scope of Application

This product is used as a fermentation activator and is reserved for fermentation operations.  It adds ammonium ions that can be directly assimilated by the yeast. The sulfates added are completely soluble in wine.

Statutory restrictions govern the addition of ammonium.

  1. Labelling

The concentration of this product should be indicated on the label, including mixtures. In addition, safety and storage conditions should be noted.

  1. Centesimal Composition

 

H2SO4

74.22

NH3

25.78

SO3

60.59

N

21.20

  1. Properties

Transparent, anhydrous crystals with a bitter, pungent taste, which are similar to potassium sulfate crystals, with which this salt is isomorphous.

  1. Solubility

Water at 20 °C

509 g/l

Water at 100 °C

1040 g/l

Alcohol, 90% by vol.

Insoluble

Acetone 

Insoluble

  1. Identifying Characteristics

 

Solutions of this salt in water in a concentration of 1 pp 100 (m/v) has a pH of approximately 5.5. This solution allows reactions of ammonium and those involving sulfates.

  1. Tests

7.1.     Sulfur Ash

The concentration of sulfur ash of ammonium sulfate prepared as explained in the annex in a test sample of 1 g must not exceed 5 g/kg.

7.2.     Preparing the Solution for Tests

Prepare a 10 pp 100 (m/v) solution.

7.3.     Chlorides

To 0.5 ml of the solution prepared for testing under paragraph 7.2, add 14.5 ml of water, 5 ml of nitric acid (R) diluted to a concentration of 10 pp 100 and 0.5 ml of 5 pp 100 silver nitrate solution (R).  After 15 minutes at rest in the dark, there should be no clouding; or else, any clouding visible should be less intense than that observed in the control prepared as indicated in the annex.  (Hydrochloric acid content must be less than 1 g/kg).

7.4.     Phosphates

To 0.5 ml of the solution prepared for tests under paragraph 7.2, add 5 ml of water and 10 ml of nitro-vanadomolybdic reagent (R). Leave in contact for 15 minutes at 20 °C. If a yellow coloring appears, it should be less intense than that obtained by adding, to 0.5 g of a solution containing 0.05 g phosphorous per liter, 5 ml of water and 10 ml of nitro-vanadomolybdic reagent.  (Phosphate content expressed in terms of phosphorous should be less than 500 mg/kg).

7.5.     Nitrates

Mix 5 ml of concentrated sulfuric acid (R) and 0.5 ml of an previously prepared iron (II) sulfate solution in a concentration of 5 pp 100 (m/v) in a test tube. Without mixing, pour 5 ml of the solution obtained by dissolving 2 g of ammonium sulfate in 10 ml of water. No coloring should be observed at the surface separating the two solutions

7.6.     Iron

To 5 ml of the solution prepared for testing under paragraph 7.2, add 1 ml of concentrated hydrochloric acid (R), one drop of 2 pp 100 potassium permanganate (R) and 2 ml of 5 pp 100 potassium thiocyanate solution (R).

If a red coloring appears, it should be less intense than that of a control prepared with 2.5 ml of an iron (III) solution in a concentration of 0.01 g of iron per liter (R), 2.5 ml of water and the same quantities of the same reagents.  (Iron content should be less than 50 mg/kg).

The proportion of iron may also be quantified by atomic absorption spectometry, using the technique detailed in the Compendium.

7.7.     Lead

Use the quantitative analysis technique detailed in the Compendium on the solution prepared for testing under paragraph 7.2.

(Lead content should be less than 5 mg/kg.)

7.8.     Mercury

Test for mercury concentration in the solution prepared for testing (7.2), using the method explained in the annex. (Mercury content should be less than 1 mg/kg.)

7.9.     Arsenic

Using the method indicated in the Annex, test for arsenic concentration in the test solution prepared in accordance with paragraph 2.  (Arsenic content should be less than 3 mg/kg.)

7.10. Quantitative Analysis of Ammonia

Dilute the test solution prepared under paragraph 7.2 to one-tenth strength, then place 10 ml of this dilute solution (0.10 g of ammonium sulfate) in a steam distillation device (described in the Annex). Add 20 ml of 30% sodium hydroxide (R) and distill 100 ml. Quantitatively analyze the distilled ammonia using 0.1 M hydrochloric acid. Let n be the number of milliliters used:

100 g of ammonium sulfate contains 1.7 n g of ammonia (NH3).

(Ammonia concentration greater than 25 pp 100.)

7.11. Quantitative Analysis of Sulfuric Acid

Dilute the test solution prepared for testing under paragraph 7.2 to one-tenth strength, then take 25 ml of this solution and add 75 ml of water and 1 ml concentrated hydrochloric acid (R).  Bring to a boil while slowly adding a small excess of barium chloride solution (R). Let the precipitate form for 30 minutes in a 100 °C water bath.  Collect the precipitate, then wash, calcine in an oven at 600 °C and weigh. Let p be the weight of the barium sulfate precipitate:

100 g of ammonium sulfate contains 16.80 p g of sulfuric acid (H2SO4).  (Sulfuric acid content greater than 73.5 pp 100.)

  1. Storage

Ammonium sulfate should be stored in a dry place in hermetically sealed containers, away from heat.

Silver (chloride)

COEI-1-CHLARG Silver[1] chloride

N° CAS : 7783-90-6

  1. Object, origin and scope of application

 

This monograph relates to silver chloride used for adsorption into an inert carrier material with a view to its use in wine.

Silver chloride is used for the treatment of wines to remove fermentation and storage-related abnormal odours (odours caused by reduction reactions, characterised by the presence of hydrogen sulphide and thiols).

Silver sulphide formed during the treatment remains adsorbed by the inert carrier material and together they can be separated by filtration.

The inert carrier materials, such as, for instance, kieselguhr (diatomaceous earth), bentonite, kaolin, etc. should comply with the prescriptions of the International Oenological Codex.

  1. Labelling

The product concentration, batch number, use-by-date, safety warnings and storage conditions should be indicated on the label.

  1. Appearance

Silver chloride, in its pure state, is a white solid matter.

  1. Composition (test trials)

The silver chloride used should have a minimum purity of 99%. Determination of the silver content is conducted according to the atomic absorption spectrophotometry (AAS) method (7.8).

The silver chloride content in the inert carrier material should be higher than or equal to 2%.

  1. Identification of silver chloride

On exposure to light, silver chloride undergoes photolytic decomposition (with darkening).

Silver chloride is partially soluble in a 3% ammoniacal solution (bromide and iodide do not go into solution in the cold) and subsequent addition of potassium iodide solution results in the precipitation of yellow silver iodide (higher sensitivity to light than AgCl). Alternatively, a diluted solution of red potassium hexacyanoferrate(III) can be added instead of iodide. A brown precipitate (Ag3[Fe(CN)6]) is formed.

  1. Solubility of silver chloride

In water at 25 °C: 0.00188 g/L.

Insoluble in alcohol and nitric acid.

Soluble in sulphuric acid, hydrochloric acid, thiosulphate and ammonium solutions upon complex formation.

  1. Tests

7.1.   Preparation of test solution

Place 0.5 g of sodium chloride and 20 mL of 0.1 mol/L sodium thiosulphate solution in a 50 mL beaker. Mix for 30 minutes. Afterwards, allow to rest/sediment for 5 minutes. Filter the supernatant using a single-use syringe with a filter, pore size 0.45 µm. Transfer 0.5 mL filtrate to a 100 mL volumetric flask and fill up to the calibration mark with distilled water.

7.2.   Appearance of test solution

The solution must be colourless, possibly cloudy. The filtrate is colourless.

7.3.   Iron

Determine the content according to the atomic absorption spectrophotometry (AAS) method described in Chapter II of the International Oenological Codex; content below 5 mg/kg.

7.4.   Nickel

Determine the content according to the atomic absorption spectrophotometry (AAS) method described in Chapter II of the International Oenological Codex; content below 5 mg/kg.

 

7.5.   Lead

Determine the content according to the atomic absorption spectrophotometry (AAS) method described in Chapter II of the International Oenological Codex; content below 5 mg/kg.

7.6.   Mercury

Determine the content according to the atomic absorption spectrophotometry (AAS) method described in Chapter II of the International Oenological Codex; content below 1 mg/kg.

 

7.7.   Arsenic

Determine the content according to the atomic absorption spectrophotometry (AAS) method described in Chapter II of the International Oenological Codex; content below 3 mg/kg.

7.8.   Silver

Determination by atomic absorption spectrophotometry (AAS), described in the Compendium of International Methods of analysis of wines an musts, after preparation of a test solution (7.1). Calibration with 1 mg/L, 2.5 mg/L and 5 mg/L Ag-reference solutions.

  1. Storage

Silver chloride must be stored in a dry place, protected from light in hermetically sealed packaging.


[1] Silver chloride used for the treatment of wine should be adsorbed into an inert carrier material

Argon

COEI-1-ARGON

Argon Ar = 40.0

N° SIN: 938

N°CAS = 7440-37-1

  1. Object, origin and field of application

Neutral gas, used for operations of inerting or degassing, it is used in a mixture of nitrogen and/or of carbon dioxide.

  1. Labelling

The label must mention the nature of the gas and refer to its composition and purity. The safety conditions must also be indicated on the packages.

  1. Characteristics

Colourless and odourless gas without flavour. Non flammable, it does not support combustion.

The weight of a litre of argon under the pressure of 760 mm of mercury is 1.784 g at 0°C. A volume of water dissolves 0.0336 volume of argon at 20°C.

  1. Test trials

The global purity of the argon used in oenology must not be less than 99% of argon in volume.

Before any measurement it is advisable to allow any gas to escape for a few minutes in order to purge the piping.

4.1. Chromatographic dosage

The search and determination of gases: Nitrogen, carbon monoxide (less than 10 µl/l), oxygen (10 ml/l), hydrogen, carbon dioxide (less than 300 µl/l), etc., are quickly obtained by chromatography in gaseous phase according to the method in chapter II of the International Oenological Codex.

The total surface are of hydrogen chromatographic peaks, of oxygen and nitrogen must not exceed 1% of gas surfaces to be examined.

The following chemical methods can also be used for oxygen.

4.2. Oxygen dosage by chemical method

Preparation of the flask for searching oxygen:

  • Introduce in a 24 ml flask about two fragments of copper turnings of 2 cm, 16 ml of ammoniac solution of copper sulphate (R), then 2 ml of hydrazine dihydrochloride solution (R).
  • Seal the flask with a rubber stopper that is easy to pierce with a needle for hypodermic injections. Crimp the neck with a metallic capsule. Then cover the capsule with wax in order to ensure perfect water tightness. Shake the flask and allow to stand away from light until complete discolouration is obtained after about eight days.

Conduct of the test trial:

  • Pierce the flask’s stopper to search for oxygen with a needle of 8/10 millimetre for hypodermic injection (take care so as not to plunge it into the liquid) that then will be used for evacuating the gas after bubbling. Then introduce a second needle of the same diameter releasing the gas and plunging it into the liquid. After a minute of bubbling, a noticeable colouration should not be observed. In the presence of oxygen, the liquid quickly becomes blue and the colour darkens with time.
  1. Packaging

The argon is supplied in highly resistant steel cylinders painted in white with needle valves. The resistance of these cylinders must be checked periodically.

Ascorbic acid

COEI-1-ASCACI Ascorbic acid

2,3-didehydro-L-threohexano-4-lactone

Acidum ascorbicum

L-Ascorbic Acid

C6H8O6 = 176.1

SIN NO. 300

  1. Objective, Origin and Scope of Application

Ascorbic acid is the enolic form of 3-oxo-L-gulofuranolactone (2,3-didehydro-L-threohexano-4-lactone).

This product falls into the category of antioxidants and is used as a reducing agent used to prevent oxidation.

Its use is subject to statutory regulations regarding limits.

 

  1. Labelling

The concentration of this product should be indicated on the label, including cases in which it is used in mixtures, as should the safety and storage conditions.

  1. Properties

Odorless white or very pale yellow crystalline powder with an acidic flavor. Aqueous solutions rapidly decay in air and light and have a maximum stability at pH 5.4.  Melting point in a capillary tube: approximately 190 °C with decomposition.

Ascorbic acid in aqueous solution has a pH of less than or equal to 3.

  1. Solubility

Water at 20 °C

290 g/l

Alcohol, 95% by vol.

320 g/l

Methanol

125 g/l

Acetone 

soluble

Benzene, chloroform, ethyl ether, petroleum ether

insoluble

  1. Rotatory Power

 

In a 10 pp 100 (m/v) aqueous solution, ascorbic acid has a specific rotatory power

is between +20,5° et +21,5°

  1. Absorption in Ultraviolet Light

Ascorbic acid in alcohol solutions in a concentration of 10 mg/l exihibits an absorption spectrum with a maximum of approximately 244 nm.

The solution has a specific extinction of:

 

approximately 560

  1. Identifying Characteristics

7.1.     Preparation of the Solution for Testing

Dissolve 5 g ascorbic acid in water and fill to 100 ml using the same solvent.

7.2.     Add 0.5 g monosodium carbonate to 2 ml of the solution prepared for testing (Par. 7.1).

7.3.     Add several drops nitric acid diluted to 10 pp 100 (R) and several drops silver nitrate in a concentration of 1 pp 100 (R) to 1 ml of the solution prepared for tests (Par. 7.1). A gray precipitate will form.

7.4.     To 1 ml of the solution prepared for testing (Par. 7.1) add one drop of recently prepared sodium nitrohexacyanoferrate (III) Na2[Fe(CN)5NO], 2H2O (sodium pentacyanonitrosylferrate) in a concentration of 5 pp 100 (m.v), and 2 ml of 10 pp 100 diluted sodium hydroxide solution (R).  Then, add 0.6-0.7 ml of concentrated hydrochloric acid (R) and stir.  The yellow color will turn to blue.

7.5.     Add drop by drop 2 ml of 2,6-dichlorophenolindophenol solution (R) to the solution prepared for testing (Par. 7.1). It will instantly become decolored.

  1. Tests

8.1.     Sulfur Ash

As determined in 1.0 g ascorbic acid, the proportion of sulfur asheshould not be greater than 1 g/kg.

8.2.     Appearance of the Solution

The solution prepared for tests under paragraph 7.1 should be clear and colorless.

8.3.     Determining pH

The pH of the solution prepared for tests under paragraph 7.1 should be between 2.4 and 2.8.

8.4.     Heavy metals

10 ml of the solution prepared for tests under paragraph 7.1 should meet the heavy metal limit requirements described in the annex.  (The heavy metal concentration  expressed in terms of lead should be less than 10 mg/kg).

8.5.     Lead

Use the technique detailed in the Compendium to analyze the solution prepared for tests (Par. 7.1). (Lead concentration should be less than 2 mg/kg).

8.6.     Mercury

Use the technique described in the annex to analyze the solution prepared for tests (Par. 7.1). (Mercury concentration should be less than 1 mg/kg.)

8.7.     Arsenic

Using the method indicated in the Annex, test for arsenic in the test solution prepared in accordance with paragraph 7.1.  (Arsenic concentration should be less than 3 mg/kg).

8.8.     Iron

Implement the atomic absorption technique described in the Compendium to analyze the solution prepared for tests (Par. 7.1). (Iron concentration should be less than 5 mg/kg.)

8.9.     Copper

Implement the atomic absorption technique described in the Compendium to analyze the solution prepared for tests (Par. 7.1). (Copper concentration should be less than 2 mg/kg.)

8.10. Moisture

Dehydration loss after drying in a desiccator under a vacuum and in the presence of sulfuric acid for 24 hours must be less than 0.4%.

8.11. Quantitative Analysis

In 80 ml of recently boiled and cooled water to which 10 ml of sulfuric acid diluted to 10 pp 100 (R) has been added, dissolve a test sample weighed precisely at about 0.20 g. Add 1 ml of starch (R) and titrate using 0.05 M iodine until a persistent blue coloration appears.

1 ml of 0.05 M iodine corresponds to 8.81 mg ascorbic acid.

The product should contain at least 99 pp 100 ascorbic acid.

  1. Storage

Ascorbic acid should be stored in tightly sealed non-metal containers in a dark place. Aqueous solutions decay rapidly in air and light.

 

 

Isoascorbic acid

Isoascorbic acid, or D-ascorbic acid or erythorbic acid has the same antioxidant power as ascorbic acid and can be used for the same oenological purpose.

This acid exhibits the same appearance and the same solubility properties as ascorbic acid.

It is, optically, the reverse of ascorbic acid and has, under the same conditions, a specific rotatory power of:

is between -20° et -21,5°

With the exception of rotatory power, this acid should exhibit the same properties as ascorbic acid, respond in the same way to the identifying reactions, pass the same tests and responds to the same quantitative analysis.

Note 1: The vitamin C efficacity of isoascorbic acid is approximately 1/20 of that of ascorbic acid.

Note 2: There is a preliminary draft resolution calling for registration of this product in the International Code of Oenological Practices.

Nitrogen

COEI-1-AZOTE Nitrogen

Nitrogenum

N = 14.007

SIN NO. 941

  1. Objective, Origin and Scope of Application

Neutral gas used to render inert or to degas.  It can be used pure or mixed with carbon dioxide.

  1. Labelling

The label should mention the nature of this gas and reference its composition and purity, as well as its safety and storage conditions.

  1. Properties

Colorless, odorless, flavorless gas.  It is not flammable and does not maintain combustion.

The weight of a liter of nitrogen under normal conditions is 1.250 g.

Under a pressure of 760 mm of mercury at 20 °C, a volume of water dissolves a 0.01507 volume of nitrogen, while a volume of alcohol dissolves a 0.1224 volume of nitrogen.

  1. Tests

The purity of nitrogen used for oenological purposes should be 99 parts per 100 by volume.

Before undertaking any measurement, the gas should be allowed to escape for several moments in order to clean out the lines.

Gas detection and quantitative analysis: oxygen, carbon monoxide, argon, carbon dioxide, etc. are most rapidly detected using gas phase chromatography.  (See this method in the Annex.)

The following chemical methods can also be used.

4.1.     Phosphorous-containing Hydrogen, Arsenical Hydrogen and Reducing Substances

Let 1 liter of nitrogen to flow into a mixture of 10 ml of ammoniacal silver nitrate (R) and 15 ml of water.

Regulate the flow of gas so that the gas flows into the solution in approximately 15 minutes.

There should be no clouding or brown coloration when compared with an identical control solution through which no gas will flow.

4.2.     Oxygen

Prepare a flask to test for oxygen as follows:

Place 2 turned pieces of copper of approximately 2 cm2, 16 ml of ammoniacal copper sulfate solution (R) and 2 ml of hydrazine dichlorhydrate in a 24 ml flask.

Stop the flask with a rubber stopper which can easily be pierced with a hypodermic needle.  Seal the collar with a metal cap, then cover the cap with wax to ensure a perfectly airtight seal.  Shake the flask, then let it sit in the dark until the color disppears completely, after approximately eight days.

Conducting the test:

Pierce the flask stopper with a 8/10 mm hypodermic needle (take care not to dip the needle into the liquid).  This will allow gas to escape after bubbling.  Next, insert a second hypodermic needle of the same diameter and plunge it into the liquid.  After a minute of bubbling, there should be no significant coloring.  In the presence of oxygen, the liquid will rapidly turn blue and the color becomes more intense over time.

The nitrogen must incorporate less than 10 ml/l oxygen.

  1. Packing and Storage

 

Nitrogen is delivered in high-strength steel canisters which are painted black and equipped with a needle valve tap.  The strength of the canisters should be checked periodically.

Lactic acid bacteria

COEI-1-BALACT Lactic acid bacteria

  1. Object, origin and field of application

Lactic acid bacteria are used in oenology to perform malolactic fermentation. The lactic acid bacteria must belong to the Oenococcus, Leuconostoc, Lactobacillus and Pediococcus genus and must be isolated from grapes, musts, wine or have been derived from these bacteria.

The use of genetically modified bacteria will be governed by the currently applicable legislation.

The strains of lactic acid bacteria must be kept under conditions which most favour their genetic stability.

Lactic acid bacteria used in oenology must transform the malic acid in must and wine into lactic acid and carbon dioxide. This should produce biogenic amines in the smallest possible quantities, and must not produce an off taste.

  1. Labelling

The following information must be indicated on the label:

  • The genus name and specie(s) in addition to the reference(s) of the strain(s) in the case that there is a registration body.
  • Selecting body
  • Operating instructions method and possible reactivation additives recommended by the manufacturer.
  • The minimum number of viable cells per gram of preparation that is guaranteed by the manufacturer,
  • The manufacturing batch number, in addition to the expiration date and storage conditions with a storage temperature recommended by the manufacturer.
  • Where relevant, the indication that lactic acid bacteria were obtained by genetic modifications and their modified character(s).
  • The additives.
  1. Characteristics

Lactic acid bacteria are marketed in liquid, frozen or powder form obtained by lyophilisation or drying, in pure culture or in association with pure cultures.

  1. Test trials

4.1.    Humidity for lyophilisated or dried bacteria

Measured by the weight loss of 5 g of the product, dried at 105 °C until constant weight (about 3 hours).

Maximum content should not exceed 8 %.

4.2.    Lead

Proceed with the determination according to the method in chapter II of the International Oenological Codex.

Content should be less than 2 mg/kg of dry matter.

4.3.    Mercury

Proceed with the determination according to the method in chapter II of the International Oenological Codex.

Content should be less than 1 mg/kg of dry matter.

4.4.    Arsenic

Proceed with the determination according to the method in chapter II of the International Oenological Codex.

Content should be less than 3 mg/kg of dry matter.

4.5.    Cadmium

Proceed with the determination according to the method in chapter II of the International Oenological Codex.

Content should be less than 1 mg/kg of dry matter.

4.6.    Viable lactic acid bacteria[1]

Proceed with counting according to the method in chapter II of the International Oenological Codex.

The number should be more or equal to 108 CFU/ml for frozen or liquid bacteria.

The number should be more or equal to 1011 CFU/g for lyophilisated or dried bacteria.

4.7.    Mould

Proceed with counting according to the method in chapter II of the International Oenological Codex.

The number should be less than 103 CFU/g.

4.8.    Contaminant acetic acid bacteria

Proceed with counting according to the methods in chapter II of the International Oenological Codex.

The number of acetic bacteria should be less than 103 CFU/g for frozen or liquid lactic acid bacteria or 104 CFU/g for lyophilisated or dried lactic acid bacteria.

The sum of Acetobacter + Gluconobacter should be less than 103 CFU/ml for frozen or liquid lactic acid bacteria or 104 CFU/g for lyophilisated or dried lactic acid bacteria.

4.9.    Yeasts contaminants

Proceed with counting according to the methods in chapter II of the International Oenological Codex.

The number of viable cells of total contaminant yeasts must be less than 103 CFU/g for lyophilisated or dried lactic acid bacteria or 102 CFU/ml for frozen or liquid lactic acid bacteria.

4.10. Salmonella

Proceed with counting according to the method in chapter II of the International Oenological Codex.

Absence should be checked on a 25 g sample.

 

4.11. Pseudomonas aeruginosa[2]

4.12. Escherichia coli

Proceed with counting according to the method in chapter II of the International Oenological Codex using a selective differential medium for Escherichia coli. MET in the annex. A lactic acid bacteria stock suspension is carried out in a trypone salt solution using 1 g of lactic acid bacteria for 10 ml of solution (total volume). 2 ml of stock solution is transferred to each dish using 5 different dishes. Absence should be checked on 1 g sample.

 

4.13. Staphylococci

Proceed with counting according to the method in chapter II of the International Oenological Codex. The presence of staphylococci is evaluated by an enrichment culture in a liquid Giolitti and Cantoni medium followed by a confirmation on a solid Baird Parker medium in the annex.

A lactic acid bacteria stock suspension is carried out in a salt tryptone solution using 1 g of lactic acid bacteria for 10 ml of solution (total volume). 10 ml of stock suspension is used to inoculate a Giolitti and Cantoni medium to Tween 80 double concentration. Cultures are incubated 48 hours at 37 °C.

In the case that the Giolitti and Cantoni medium gives positive results, the presence of Staphylococci is confirmed by isolation on a solid Barid Parker medium. A positive culture medium loop is used to inoculate solid BP mediums to obtain isolated colonies.

Absence should be checked on 1 g sample.

 

4.14. Coliforms

Proceed with counting according to the method in chapter II of the International Oenological Codex using a selective differential medium for coliforms, desoxycholate gelose in the annex. A lactic acid bacteria stock suspension is carried out in a salt tryptone solution using 1 g of lactic acid bacteria for 10 ml of solution (total volume). 2 ml of stock solution are transferred is each dish using 5 different dishes.

The number of coliforms should be less than 102 CFU/g.

  1. Additives

They must be in conformity with regulations in force.

  1. Storage conditions

Always refer to manufacturer’s recommendations.

Appendix: Preparation of a leaven “pied de cuve malo” to innoculate 100hL of wine or any volume from the values in brackets in %, the quantities of powder are expressed in g/L


[1] Except for specific bacteria intended for acidic wines (pH up to 2.85) that should be used with a pre-multiplication process (see Annex) in the must or wine, where the population cannot be less than 109 CFU/g.

Reference: Bridier, J., O. Claisse, M. Coton, E. Coton and A. Lonvaud-Funel (2010). "Evidence of distinct populations and specific subpopulations within the species Oenococcus oeni." Appl Environ Microbiol 76(23): 7754-7764.

[2] Point to be studied at a later date by the expert group “Microbiology”.

Bentonites

COEI-1-BENTON Bentonites

Bentonita

N° SIN: 558

  1. Object, origin and field of application

Bentonites are hydrous aluminium silicates belonging to the montmorillonite group. The brute formula is:

Si4 (Al (2-x) Rx) (O10, H2O)(Cex, nH2O) or  Si4(Al(2-x)Rx)(H2O)n where:

R = Mg, Fe, M, Zn, Ni

Ce (exchangeable cations) = Ca, Na, Mg.

Bentonites are used for clarification operations or protein stabilisation in musts and wine. Bentonites fix to certain unstable proteins which allows them to be eliminated.

Bentonites are capable of fixing coloured matter.

  1. Labelling

The nature of the bentonite (natural sodium, calcium, and activated calcium), batch number and the optimal expiration date for activated bentonites will be indicated on the label. The mention of risks and safety concerning the presence of crystalline silica should also be indicated.

2.1.    Natural Bentonites:

Depending on the nature of the of exchangeable cations present, there are 2 naturally occurring types of bentonite:

  • Sodium bentonite, it swells and absorbs readily where sodium is the major exchangeable cation.
  • Calcium bentonite, where calcium is the major exchangeable cation, it is lower swelling and lower absorbent than sodium bentonites.

These two types of betonites are simply grinded before their commercialisation after possibly being dried at 80°C to 90°C.

2.2.    Activated bentonites:

In order to improve the adsorption properties of calcium betonites, they are most often activated by sodium carbonate, then dried and grinded. This results in activated calcium bentonites with properties equal or superior to sodium bentonites.

The properties of these bentonites thus activated or permuted are less stable in time (3 to 18 months) and depend on the activation of magnesium, calcium, and sodium levels.

These different types of bentonites are in the form of powder, spherical or cylindrical granules. Colour can vary from white for the purest products to grey, beige or green for others.

  1. Test trials

3.1.    Odour

Bentonite should not have any undesirable odour (e.g. no mould) and should not change the taste of wine.

3.2.    pH level

Shake 5g of bentonite with 100 ml of distilled water for 5 minutes. Allow to stand for 1 hour. Measure the pH level of the supernatant liquid. Natural calcium bentonites have a neutral pH (level around 6.5 to 8.5) whereas activated calcium bentonites have a much more alkaline pH (level around 8.5 to 10.0). Natural sodium bentonites have a wider range of pH (level around 4.7 to 10.0).

3.3.    Loss during desiccation

The desiccation of 5 g of bentonite at 105°C during 4 hours causes a weight loss of 5% to 15% of the initial weight (often around 10%).

3.4.    Preparation of the test trial solution

Weigh p g of bentonite containing 10 g of anhydrous bentonite.

In a 500 ml flask with a large opening which can be hermetically sealed, add 100 ml of tartaric acid solution to 5 g per litre until the solution has a pH level of 3 (R). Sprinkle the bentonite trial sample in the constantly shaken solution (for example using a magnetic stirrer) and a funnel. After this addition, shake vigorously for 5 minutes. Allow to stand for 24 to 48 hours. Decant, centrifuge or filter if necessary to obtain at least 100 ml of clear liquid.

All the following set limits for bentonite are for the weight of dried bentonite.

3.5.    Montmorillonite content

Minimum rate:

  • Manufacturer indicates that the content should not be under 80% by x-ray diffraction analysis.

3.6.    Different forms of free silica content

  • Crystal silica content must be less than 3% (quartz N° CAS 14080-60-7, cristobalite N° CAS 14464-46-1).
  • Particle holdings under 10 microns must be less than 10%.
  • Respirable crystal silica content must be under 0.3%.

These standards must be written on the security form supplied by the manufacturer.

3.7.    Lead

In the test trial solution (3.4) determine the lead content using the method described in Chapter II.

Lead content must be less than 5 mg/kg.

3.8.    Mercury

Determine the mercury content according to the method described in Chapter II with the test trial solution (3.4).

Mercury content should be less than 1 mg/kg.

3.9.    Arsenic

Determine the arsenic content of 5 ml of test trial solution (3.4) according to the method in Chapter II.

Soluble arsenic content should be less than 2 mg/kg.

3.10. Iron

Add 12.5 ml of water, 1 ml concentrated hydrochloric acid (R) and 2 ml of potassium thiocyanate at 5% (R) to 5 ml of the test trial solution (3.4). The red coloration should be lighter than what is obtained when using 2.5 ml citric acid at 5% at pH 3 (R), 1 ml concentrated hydrochloric acid (R), 15 ml of iron salt solution (III) at 0.010 g of iron per litre (R) and 2 ml of potassium thiocyanate solution at 5% (R).

Iron content should be less than 600 mg/kg).

Iron can also be determined by atomic absorption spectrometry according to the method in Chapter II.

3.11. Aluminium

On the test trial solution (3.4), find extractable aluminium according to the method described in Chapter II.

Extractable aluminium content should be less than 2.5 g/kg.

3.12. Calcium and magnesium

On the test trial solution (3.4), determine calcium and magnesium using the methods outlined in the Compendium of International Methods of Analysis of Wine and Musts.

Calcium and soluble magnesium combined should be less than 100 meq for 100 g.

3.13. Sodium

On the test trial solution (3.4), determine sodium using the method outlined in the Compendium of International Methods of Analysis of Wine and Musts.

Soluble sodium content should be less than 10 g/kg for natural bentonites and less than or equal to 35 g/kg for activated bentonites.

3.14. Presence of large particles

  • Put 1 litre of water in a 1.5 litre long stem glass.
  • Slowly add while shaking the liquid, a quantity of bentonite corresponding to 50 g of dried bentonite.
  • Shake vigorously 2 to 3 minutes and allow to stand for 24 hours.
  • Shake 2 to 3 minutes and allow to stand for 2 minutes.
  • Using a siphon, take off 9/10 of the cloudy liquid exceeding 100 ml and leave the deposits at the bottom of the glass.
  • Add 900 ml of water.
  • Shake 1 minute.
  • Allow to stand for 2 minutes and repeat to obtain 5 washings.
  • Remove the deposit and put in a capsule.
  • Dry and weigh.
  • The residue must be less than 8 g for 100 g.

3.15. De-acidification tests trials

  • Weigh (p) of bentonite containing 0.2 g of dried bentonite.
  • Put this in a 125 ml flask containing 50 ml of citric acid 0.033 M solution (R).
  • Shake vigorously for 5 minutes and allow to stand for 30 minutes.
  • Either filter or centrifuge.
  • Take 10 ml of filtrate and titrate with an acid solution of 0.1 M of sodium hydroxide with a drop of phenolphthalein solution (R), that is n ml the volume poured to obtain a colour change in the indicator: 250 (10 – n) is the number of milliequivalent of acids fixed or neutralised for 100 g of bentonite.
  • The maximum limit is 2.5 eq/kg.

3.16. Rate of swelling

Swelling indicator: specific test is necessary.

2 g of bentonite is strewn over 100 ml of demineralised water and 100 ml of wine in a graduated test tube cylinder. After 24 hours, weigh the volume of bentonite. This will be expressed in ml/g of dried product.

3.17. Protein adsorption test trial (for bentonite to go through deproteinisation)

3.17.1.     Preparation of test trial solution:

Mix 5 g of egg white with a sufficient amount of citric acid solution of 5 g per litre (pH=3) to make 1 litre. Filter. Determine total nitrogen on 100 ml of this solution by using the procedure described in Chapter II. This solution contains approximately 90 mg of total nitrogen for 575 mg of proteins per litre.

3.17.2.     For each test trial using 100 ml of this solution, mix increasingly larger doses of bentonites prepared in a 5% suspension in order to process doses of 0.1 to 0.8 g/l. Shake vigorously and maintain at 15°C–20 °C for 6 hours. Centrifuge and proceed with determinations of nitrogen or residual proteins.

A de-proteinising bentonite should eliminate at least 50% of the proteins in a synthetic solution with a 0.4 g/l dose.

3.18. Determining the specific adsorption surface (or the adsorption indicator for methylene blue)

See method described in annex.

The accepted limit should be 300 mg/100g.

  1. Storage

Bentonites must be stored in a ventilated area in watertight containers away from volatile objects that they could adsorb.

Annex: Determination of the specific surface of adsorption of bentonite

  1. General information

1.1.    Aim of the test trial

This test trial enables to measure the capacity of bentonite to adsorb methylene blue.

Clays, organic matters, and iron hydroxide preferentially adsorb methylene blue. This capacity takes into account the activity on the surface of these elements. We call, “blue value” of bentonites, the quantity expressed in grams of methylene blue adsorbed per 100 g of bentonites.

1.2.    Principle of the test trial

Elemental doses of a methylene blue solution are injected successively into an aqueous solution containing the trial sample. The adsorption of blue is checked after each addition by making a spot on a paper filter (spot test, see paragraph 5).

For a simple conformity check, the specified quantity of blue is injected once.

  1. Equipment and reagent

2.1.    A 25 ml burette graduated 1/10 ml.

2.2.    Paper filter: quantitative and without ashes (< 0.010); weight: 95 g/m2; thickness: 0.20 mm; filtration speed 75; retention: 8 micrometers.

2.3.    A glass rod: 300 mm length; 8 mm diameter.

2.4.    A magnetic stirrer and magnetic stirring bar.

2.5.    Methylene blue of medicinal quality at 10g/l 0.1 g/l.

The maximum duration for using the solution is one month. The solution must be stored away from light.

2.6.    Demineralised or distilled water.

  1. Preparation of test trial samples

Add 10 g of bentonite in 200 ml of distilled water, allow to swell for 2 hours, then homogenise by shaking.

  1. Carrying out test trial

4.1.    Definition of spot test

After each addition of blue (see paragraph 5.2), this test involves taking a drop of suspension that is placed on a paper filter using a glass rod. The spot that is formed is composed of a central deposit of matter, blue in colour surrounded by a humid colourless area.

The drop must be such that the diameter of the deposit is between 8 and 12 mm.

The test is positive if a persistent light blue ring appears around the middle deposit in the humid zone. The test is negative if the ring is colourless.

4.2.    Determination

Using a burette, pour 2 ml of blue solution in a container with 200 ml of suspension of bentonite maintained in agitation. After 2 minutes, add 1 ml of blue solution. This addition is followed by the spot test on filter paper.

Allow the asorption of blue to occur which is not instantaneous. Meanwhile tests should be conducted minute by minute.

If the light blue ring disappears at the fifth spot, proceed with elemental additions of 0.2 ml of blue and then 0.1 ml.

Each addition is followed by tests conducted minute by minute.

Renew these operations until the test remains positive for 5 consecutive minutes: the determination is considered as ended.

That is V ml poured.

  1. Expression of results

5.1.    Blue value

The blue value expressed in grams of blue for 100 g of bentonite is shown in the following formula:

  • V is the value of blue methylene poured in ml.

5.2.    Conformity check compared to a given specification

The specification is expressed in blue value for 100 g of bentonite, or s of this value.

The volume of blue solution to be added in one time to the preparation (3) is:

The spot test is done after eight minutes of shaking. If it is negative, the bentonite complies with the specification.

Beta-glucanase

COEI-1-BGLUCA Beta-Glucanases from Trichoderma Sp.

(E.C. 3-2-1-58)

(C.A.S. No. 9073-49-8)

Glucan 1,3-beta-glucosidase

(exo-1,3-beta-glucosidase; beta-1,3-glucan exo-hydrolase; exo-1,3-beta-glucanase; endo-1,3-beta-glucanase)

and glucan 1,6-beta-glucosidase

General specifications

The specifications must comply with general specifications for enzymatic preparations that appear in the International Oenological Codex.

  1. Object, origin and field of application

The degradation of beta-glucans present in wines, in particular those from grapes affected by Botrytis cinerea or yeast glucans. These molecules of a very high molecular weight hydrolyse the beta-1,3 and beta-1,6 bonds of 1,3 (1,6)-beta-D-glucans with glucose production.

Secondary activities: hemicellulases, cellulases.

The beta-1,3-D-glucanases are produced from Trichoderma harzianum .and/or Trichoderma ressei

The preparation of the enzyme is without any harmful consequences as is production and purification.

Beta-glucanases do not contain any substances, micro-organisms nor collateral enzymatic activities that can:

  • be harmful to health,
  • be harmful to the quality of the products treated,
  • lead to the formation of undesirable products or flavour problems.

There are regulatory limits for the use of beta-glucanases in wine.

  1. Labelling

The concentration of the product must be indicated on the label, as well as the safety conditions, storage conditions and the expiry date.

 

  1. Characteristics

In general, it is greyish to light brown amorphous powder or light brown to dark brown liquids or granules.

  1. Solubility

Soluble in water and practically insoluble in ethanol.

  1. Enzymatic activity

Activity is the quantity of enzyme necessary for liberating in standardised conditions (see activity measured according to a method to be described), a quantity of reducing sugars corresponding to 1 µmole of glucose per minute.

Remark: the enzyme produced according to paragraph 6 simultaneously has beta-1,3-glucanase and beta-1,6-glucanase activities which gives it the sought oenological properties.

  1. Source of enzyme and production means

The beta (-1,3-1,6) glucanases are produced by submerged culture of a selected non pathogenic, non toxic strain of Trichoderma harzianum and/or Resei that is not genetically modified, in pure culture.

  1. Diluents, preservatives and additives

The preparation of beta-glucanase is generally in the form of granules. These products are prepared with food diluents or food additives such as maltodextrin, sodium citrate, citric acid, starch or glucose.

  1. Test trials

8.1. Loss at desiccation: Less than 10%. (does not apply to liquid preparations)

8.2. Ashes/Sulphuric ashes

Determine the sulphuric cinders according to the method in Chapter II of the International Oenological Codex.

The rate of sulphuric ashes of beta-glucanases should not be more than 2% of dry matter.

8.3. Preparation of the test solution

Dissolve 5 g of beta-glucanases in 100 ml of water.

8.4. Heavy metals

Add 2 ml of buffer solution pH 3.5 (R) and 1.2 ml of thioacetamide reagent (R) to 10 ml of the test trial solution (8.3). No precipitate should form. If a brown colouration appears, it should be

lighter than the control prepared as indicated in Chapter II of the International Oenological Codex.

The heavy metal content expressed in lead should be less than 30 mg/kg.

8.5. Arsenic

In 2 ml of test trial solution (8.3), search by the method indicated in

  • Chapter II of the International Oenological Codex.

Arsenic content should be less than 3 mg/kg.

8.6. Lead

Using the test trial solution (8.3) determine the lead according to the method described.

Lead content should be less than 5 mg/kg.

8.7. Mercury

Using the test trial solution (8.3) determine the mercury according to the method described in Chapter II of the International Oenological Codex.

Mercury content should be less than 0.5 mg/kg.

8.8. Cadmium

Using the test trial solution (8.3) determine the cadmium according to the method described in chapter II of the International Oenological Codex.

Cadmium content should be less than 0.5 mg/kg.

8.9. Biological contaminants

Total microorganisms

less than 5 104 CFU/g of preparation

Total bacteria

less than 103 CFU/g of preparation

Total coliforms

less than 30 CFU/g of preparation

Escherichia coli

absence checked on a 25 g sample

St. aureus[1]

absence checked on a 1 g sample

Salmonella

absence checked on a 25 g sample

Sulfitoreducing anaerobia

less than 30 CFU/g of preparation

Yeasts

maximum content 102 CFU/g of preparation

Total lactic bacteria

absence checked on a 10 g sample

Acetic bacteria

maximum content 102 CFU/ g of preparation

Moulds

maximum content 102 CFU/g of preparation

Antibiotic activity[2]

not detectable

Mycotoxins[3]

not detectable

  1. Storage

In a solid form, the preparation can be stored for several years and in a liquid form for several months at a low temperature (+5°C).


[1] Method to be defined by the Sub-Commission of Methods of Analysis

[2] Method to be defined by the Sub-Commission of Methods of Analysis

[3] Method to be defined by the Sub-Commission of Methods of Analysis

Pieces of oak wood

COEI-1-WOOPIE Pieces of oak wood

  1. Object, origin and field of application

Pieces of oak wood used for winemaking and for passing on certain constituents to the wine in conditions set by regulations.

The pieces of oak wood must come exclusively from the Quercus genus.

They can possibly be left in their natural state or they can be heated to a low, medium or high temperature but they must not be charred including on the surface, nor be carbonaceous, nor friable when touched.

No compound should be added to them for the purpose of increasing their natural aromatising capacity or their extractible phenolic compounds.

Likewise, they must not undergo any chemical, enzymatic or physical treatment other than heating.

  1. Labelling

The label must mention the varietal origin of the oak and the intensity of any heating, the storage conditions and safety precautions.

  1. Dimensions

The dimensions of these particles must be such that at least 95% in weight be retained by the screen of 2 mm mesh (9 mesh).

  1. Purity

The pieces of oak wood must not release any substances in concentrations which may be harmful to health,

  1. Storage conditions

The pieces of oak wood must be stored in sufficiently dry and odourless conditions free from substances liable to contaminate them.

  1. Introduction in wine

Where bags or other containers are used as the means of introducing pieces of oak wood or related support system into wine, they must be made from materials that are approved for food contact in the country of use, and which do not release any substances into the wine in concentrations which may be harmful to health, or jeopardise to the quality of the final product.

Annex A: Determination of the size of pieces of oak wood by screening

 

  1. Introduction

The use of pieces of oak wood, commonly called chips, to treat wine is authorised provided they comply with the specifications of the Oenological Codex (resolution OENO 3/2005). In particular, the pieces of oak wood used must meet a size requirement, and it is specified that "The dimensions of these particles must be such that at least 95% in weight be retained by the screen of 2 mm mesh (9 mesh)". The following operating procedure provides a method of sampling and then screening that can be used to verify this requirement.

  1. Field of application

The method applies to oak wood test samples of more than 0.5 kg.

  1. Principle

After dividing up the initial test sample, a known quantity of pieces of oak wood (approximately 200g) is placed on a vibrating screen. By weighing the pieces of oak wood remaining on the screen after shaking, it is possible to determine the percentage by weight of particles retained by the screen.

  1. Equipment
  • Standard laboratory equipment.
  • Screen of 2 mm mesh (9 mesh), 30 cm in diameter, mounted on a vibrating plate provided with a recovery tray.
  • Weighing machine capable of weighing to within 0.1 g.
  • Slotted test specimen divider (see figure below as an example).

Slotted test sample divider (EN 1482-1: 2007

Scheme proposed as an example

  1. Division of test sample

When the size of the test sample has to be reduced to obtain “sub-samples” of 200 g which retain a homogeneous nature representative of the initial test sample, a slotted test sample divider can be used which allows random separation of the test sample into 2 parts.

The test sample is poured entirely into the divider in order to separate it into two statistically equivalent parts. Half is put aside, while the other half is again split by means of the chip spreader. This operation is repeated as often as necessary, half being eliminated at each stage with the aim of obtaining 2 “sub-samples” of about 200 g each.

  1. Operating procedure
  • Weigh the empty screen (WES).
  • Weigh the empty recovery tray (WET).
  • Tare the screen + recovery tray unit and place on it about 200 g of pieces of oak wood weighed to within 0.1 g. Let WOAK be the weight of the pieces of oak wood to be screened.
  • Place the unit on the vibrating plate and close the cover with the clamping loops.
  • Start up the device and allow it to vibrate for 15 minutes.
  • Weigh the screen containing the remaining particles that have not passed through the 2mm meshes (WPS).
  • Weigh the recovery tray containing the particles that have passed through the screen (WPT).

A second test is performed in these conditions on the second sub-sample of pieces of oak wood coming from the same initial test sample.

Comment: Weighing of the recovery tray before and after screening (WRT and WPT) serves to verify that there has been no loss of test sample during the operation.

One should have:

  1. Calculation

The percentage (by weight) of particles retained by the screen of 2mm mesh is given by the following formula:

This calculation is performed for each of the 2 sub-samples coming from the initial test sample; the percentage of particles retained corresponds to the mean of the 2 results.

  1. Bibliography
  • Resolution OENO 3/2005 PIECES OF OAK WOOD
  • EN1482-1 - Fertilizers and liming materials.  Sampling and sample preparation.  Part 1: Sampling.

Wood for wine containers

COEI-1-WOOCON Wood for wine containers

  1. Subject, origin and scope

 

The wood of containers used during the making, storage or transport of wines.

The pieces of wood must exclusively originate from species recognized as being suitable to store wine (oak, chestnut)

They can possibly be left in their natural state or they can be heated to a low, medium or high temperature, but they must not be charred, including on the surface, nor be carbonaceous, nor friable when touched.

No compound should be added to them for the purpose of increasing their natural aromatizing capacity or their extractable phenolic compounds.

They must not undergo any chemical, enzymatic or physical treatment other than heating when used for new containers.

If they have undergone chemical or physical treatment, in particular to clean containers having already been used, it is recommended to ensure the perfect harmlessness of any such treatment for materials in contact with foodstuffs, and in particular to ensure that sufficient rinsing has eliminated any trace of certain products that are not authorized in wine.

  1. Container marking and/or accompanying document

Container markings or the accompanying document must indicate the origin of the botanical species of wood, the intensity of any heating and the safety instructions.

  1. Purity

Wooden containers must not release substances in concentrations which may be harmful to health.

  1. Storage

Wooden containers must be washed before first use and then stored under suitable conditions to prevent any development of undesirable micro-organisms when the containers are empty.

Calcium carbonate

COEI-1-CALCAR Calcium carbonate

Calcii carbonas

CaCO3 = 100.1

SIN NO. 170

  1. Objective, origin and scope of application

This product is used for deacidification.  The transport of calcium ions causes salification of free tartaric acid.  The use of calcium carbonate is also authorized when using the so-called "double salt" method of deacidification.  It may then contain small quantities of calcium tartromalate (double salt) and/or calcium tartrate There are regulations governing the use of this product..

  1. Labelling

The label should indicate the proportion of pure ccalcium carbonate and the safety and storage requirements.

  1. Centesimal composition

Carbon dioxide

43.97

Calcium

40.04

  1. Properties

Calcium carbonate exists as a white powder with the reaction properties of carbonates.  In solution in a concentration of 5 pp 100 (m/v) in dilute acetic acid (R), it yields calcium reactions.

  1. Solubility

Insoluble in water

Insoluble in alcohol at 95% by vol.

Soluble with effervescence in dilute acetic acid, hydrochloric acid and nitric acid solutions

  1. Tests

6.1.     Desiccation loss

Weigh 2 g calcium carbonate in a dish. Place in an oven at 200 °C for 4 hours. Weight loss should not exceed 2 pp 100.

6.2.     Substances Soluble in Water

Mix 2 g of ground calcium carbonate with 20 ml of boiled water.  Filter. Collect 10 ml.  The solution should be neutral. Dry evaporate.  The residue should not be greater than 1 pp 100l.

6.3.     Ammoniacal Ions

Place 2 g of calcium carbonate, 25 ml of distilled water and 5 ml of 30 pp 100 sodium hydroxide solution (R) in the flask of a distillation device.

Distill and collect 20 ml distillate in 40 ml 4 pp 100 boric acid (R) in the presence of methyl red (R).  Two drops of 0.1 M hydrochloric acid solution should be sufficient to cause the indicator to turn color.

6.4.     Barium

Dissolve 0.50 g of calcium carbonate in 10 ml of nitric acid diluted to 10 pp 100 (R). Add 10 ml of saturated calcium sulfate solution (R). The mixture should remain llear.

6.5.     Preparing the Solution for Tests

Dissolve 10 g of calcium carbonate in 100 ml of 10 pp 100 dilute acetic acid (m/v) (take care as there will be effervescence due to the release of carbon dioxide).

6.6.     Magnesium

Use the method described in the Compendium on the solution prepared for testing under paragraph 6.5. (Content should be less than 1 pp 100 by weight).

6.7.     Iron

Use the atomic absorption spectrometry method described in the Compendium on the solution prepared under paragraph 6.5. (Iron content should be less than 300 mg/kg).

6.8.     Lead

Using the technique described in the annex to quantitatively analyze the lead in the solution prepared for testing (Par. 6.5). (Lead content should be less than 2 mg/kg).

6.9.     Mercury

Implement the technique described in the annex to quantitatively analyze the mercury in the solution prepared for testing (Par. 6.5). (Mercury content should be less than 1 mg/kg).

6.10. Arsenic

Using the method described in the annex, test for arsenic in the solution prepared for testing (Par. 6.5). (Arsenic content should be less than 3 mg/kg).

6.11. Sodium

In accordance with the method described in the Compendium, quantitatively determine sodium content by flame photometry in the solution prepared for testing (Par. 6.5). (Sodium content should be less than 500 mg/kg).

6.12. Quantitative Analysis

Dissolve a precisely weighed sample p of about 2 g in 50 ml of a 1 M hydrochloric acid solution.  Bring to a boil.  Allow to cool and and titrate the excess hydrochloric acid solution using 1 M sodium hydroxide solution and methyl red (R). Let n be the amount in ml of 1 M sodium hydroxide solution used:

1 ml of 1 M hydrochloric acid corresponds to 0.05005 g calcium carbonate.  Parts per 100 of calcium carbonate in the product tested:

The wine-making product must contain a minimum of 98 pp 100 calcium carbonate.

  1. Storage

Calcium carbonate should be stored in a dry place in hermetically sealed containers away from volatile elements it could adsorb.

Potassium carbonate

COEI-1-POTCAR Potassium carbonate

Potassium carbonate anhydrous (K2CO3, CAS No. 584-08-7)

Potassium carbonate hydrate (2K2CO3 · 3H2O, CAS No.: 6381-79-9)

 

  1. Objective, origin and scope of application

The addition of potassium carbonate can be used to deacidify musts and wines.

  1. Labelling

The label should indicate the product's purity, lot code, date of manufacture, storage conditions and expiration date.

  1. Characteristics

Anhydrous potassium carbonate (K2CO3) is the potassium salt of carbonic acid and occurs as a white, odourless, hygroscopic powder. The hydrate form (2K2CO3 · 3H2O) occurs as small, white, translucent crystals or granules.

 

  1. Identifying characteristics

 

  • Solubility: Very soluble in water, insoluble in ethanol (95% by vol).
  • Carbonate: Potassium carbonate is soluble with effervescence in dilute acetic acid or hydrochloric acid solutions, evolving a colourless gas (CO2) that, when passed into calcium hydroxide solution, produces a white precipitate immediately.
  • Potassium: The presence of potassium imparts a violet colour to a non-luminous flame if not masked by the presence of small quantities of sodium.
  1. Tests

The limits are determined according to the values observed during production in line with the good manufacturing practices.

5.1.  Desiccation Loss

Through the desiccation of 3 g of potassium carbonate for 4 hours at 180°C, for the anhydrous form, the loss of weight must be lower than 1%, for the hydrate form, the loss of weight must be between 10,0% and 16,5%.

 

5.2.  Preparing the Solution for Tests

Dissolve 1 g of potassium carbonate in 20 mL water.

5.3.  Substances Insoluble in Water

Filter the solution prepared for testing under Paragraph 5.2. on a membrane of cellulose ester with a diameter of the pore lower or equal to 0,5 μm, no residue can be detected.

5.4.  Iron

Using the atomic absorption spectrometry technique detailed in chapter II of the International Oenological Codex, determine the iron content in the test solution (5.2); the content should be less than 10 mg/kg.

5.5.  Lead

Using the technique set forth in chapter II of the International Oenological Codex, determine the lead content in the test solution (5.2); the content should be less than 5 mg/kg.

5.6.  Mercury

Using the technique described in chapter II of the International Oenological Codex, determine the mercury content in the test solution (5.2); the content should be less than 1 mg/kg.

5.7.  Arsenic

Using the technique described in chapter II of the International Oenological Codex, determine the arsenic content in the test solution (5.2); the content should be less than 3 mg/kg.

5.8.  Sodium

Determine the sodium content in the test solution (5.2) using flame photometry described in chapter II of the International Oenological Codex; the content should be less than 1%.

5.9.  Cadmium

Using the technique described in chapter II of the International Oenological Codex, determine the cadmium content in the test solution (5.2); the content should be less than 1 mg/kg.

5.10.        Potassium Carbonate Content

Sample: 1 g previously dried.

Analysis: Transfer sample to a beaker and dissolve it in 50 mL water. Add 2 drops of methyl red TS and, while constantly stirring, slowly titrate with 1 N hydrochloric acid until the solution becomes faintly pink. Heat the solution to boiling, cool, and continue titration until the faint pink colour no longer fades after boiling.  The product intended for wine-making should contain a minimum of 98% potassium carbonate.

  1. Storage

 

Potassium carbonate should be stored in airtight containers.

Calcium phytate

COEI-1-CALPHY Calcium phytate

Calcium inositol hexaphosphate

Calcii phytas

C6H6Ca6O24P6,3H20= 942.11

  1. Objective, Origin and Scope of Application

Calcium phytate is the salt of the inositol hexaphosphoric ester, or inositohexaphosphoric or phytic acid.

In its calcium and magnesium double salt forms, phytic acid composes phytin, a reserve form of phosphorous in plants.

Since it is an iron (III) complexing agent approved for removal of excess iron in wines, its use must be strictly monitored.

Any excess phytate with respect to the iron (III) content causes deposits to build up when the slightest oxidation occurs.

  1. Labelling

The label should indicate product concentration even when used in mixtures, as well as its safety and storage conditions.

  1. Properties

White powder with an acidulous taste, which is minimally soluble in water, soluble in dilute strong acids, and difficult to dissolve in wine, in which solubility is incomplete.

Aqueous calcium phytate solution possess an acidic nature, which is disclosed by movement of the indicator to litmus.  It yields calcium reactions.

  1. Tests

4.1.     Desiccation Loss

Dry a 1 g sample of calcium phytate in an oven at 105 °C until a constant weight is obtained.  Weight loss should be less than 12 pp 100.

Limits indicated below are for dry product.

4.2.     Ash

Incinerate a 0.250 g test sample of calcium phytate at 550 °C.  The residue should not be less than 65 pp 100 nor greater than 72 pp 100 of the dry product contained in the test sample.

4.3.     Insoluble Substances

Prepare a first solution contaning 1 g of calcium phytate, 7 ml of 1M hydrochloric acid solution, and 93 ml of distilled water.  Separately, prepare a solution of 1 g of calcium phytate with 50 ml of distilled water and 1.5 ml pure phosphoric acid (R). Filter each of the solutions separately and collect the deposit. Wash and dry the deposit at 100 °C. Each residue should be less than 1 part per 100 (10g/kg) of dried product at 105 °C.

4.4.     Starch

Add several drops of iodinated water (R) to the residues obtained under Paragraph 4.3; no blue coloration should develop.

4.5.     Sugars

  • Stir 3 g of calcium phytate with 15 ml of distilled water.
  • Filter.
  • The filtrate should not reduce the cupro-alkaline reagent (R) before or after the sucrose inversion.

4.6.     Albumin

  • Dissolve 1 g of the product in a mixture of 1 ml of concentrated hydrochloric acid (R) and 3 ml of distilled water.
  • Add 3 ml of 30% sodium hydroxide solution (R).
  • Filter.
  • When one drop of 4 pp 100 (m/v) copper (II) sulfate solution is added to the filtrate, no violet color should appear.

4.7.     Preparing the Solution for Tests

Macerate a quantity of calcium phytate containing 5 g dry product with 100 ml of 10 g per liter citric acid (R) for 24 hours while agitating from time to time. Filter.

4.8.     Iron

  • Add 1 ml of concentrated hydrochloric acid (R) and 2 ml of 5 pp 100 potassium thiocyanate to 10 ml of test solution prepared under paragraph 4.7.
  • The resulting colorating should be less intense than that produced by a control tube prepared with 2.5 ml solution in a concentration of of 0.010 g of iron per liter (R), 7.5 ml of distilled water, 1 ml of concentrated hydrochloric acid (R) and 2 ml of 5 pp 100 thiocyanate (R).  (Iron content should be less than 50 mg/kg).

4.9.     Lead

Using the method described in the Compendium, quantify lead analytically in the test solution prepared according to Par. 4.7.  (Lead content should be less than 5 mg/kg).

4.10. Mercury

Using the method described in the annex, quantify mercury analytically in the test solution prepared according to Par. 4.7.  (Mercury content should be less than 1 mg/kg).

4.11. Arsenic

Using the method described in the annex, quantify arsenic analytically in the test solution prepared according to Par. 4.7.  (Arsenic content should be less than 3 mg/kg).

4.12. Mineral phosphates

  • Place 0.50 g calcium phytate in a 200 ml volumetric flask.
  • Add 100 ml of distilled water and 5 ml of concentrated nitric acid (R).
  • Agitate for 15 minutes at 20 °C and top off to 200 ml with distilled water.
  • To 10 ml of this solution, add 10 ml of nitro-vanadomolybdic reagent (R).
  • Leave in contact for 15 minutes at 20 °C.  The resulting color should be less intense than that produced by adding 5 ml distilled water and 10 ml nitro-vanadomolybdic reagent (R) to 5 ml of a monopotassic phosphate solution containing 0.05 g phosphorous per liter (R).
  • (Mineral phosphate content, expressed in terms of phosphorous, should be less than 1 pp 100).

4.13. Glycerophosphates

  • Heat 0.50 g of calcium phytate in the presence of monopotassic sulfate.
  • No acrolein fumes (odor of burnt horn) should be released.

4.14. Total Phosphorous Determination

  • Weigh precisely a 0.25 g sample of calcium phytate which has already been dried at 105 °C.
  • Place it in a flask which is ground and polished so it can be fitted with a tube 8 mm in diameter and 1 m long which will serve as a reflux condenser.
  • Add 5 ml of concentrated sulfuric acid (R) and 0.5 ml concentrated nitric acid (R).
  • Bring to boiling under reflux for approximately 15 minutes.
  • After cooling, decant the contents of the flask diluted with water in a 1 liter volumetric flask.
  • Wash the condenser and flask with water by pouring these liquids in the volumetric flask, and fill to gauge line after bringing the temperature to 20 °C. Agitate.
  • Add 10 ml of nitro-vanadomolybdic reagent (R) to 10 ml of this solution.  Agitate in a 20 °C water bath and let sit in the water bath for 15 minutes.  The intensity of the resulting color should be equal to or greater than that of a control prepared under the same conditions using 8 ml of monopotassic phosphate solution in a concentration of 0.05 g of

phosphorous per liter (R), 2 ml of water and 10 ml of nitro-vanadomolybdic reagent (R).

Total phosphorous analysis can also be determined using a spectrophotometer with a wavelength of 425 nm whose calibration curve was obtained based on 4-6-8-10 ml of solution in a concentration of 0.05 mg phosphorous per liter (R).

Calcium phytate should contain at least 15 parts of phosphorous per 100 , as compared with a product dried at 105 °C.

  1. Storage

Calcium phytate should be stored in a dry place in hermetically sealed containers.

Calcium tartrate

COEI-1-CALTAR Calcium tartrate

Dextrorotatory Calcium Tartrate

Calcium tartaricum

(OOC-CHOH-CHOH-COO) Ca, 4H2O

Tetrahydric L(+)-2,3- calcium dihydoxybutanedioate

(OOC-CHOH-CHOH-COO) Ca, H2O

C4H12CaO10 = 260.13

SIN No. 354

  1. Objective, Origin and Scope of Application

A natural wine salt primarily originating from wine residues.  It is therefore typically found in L(+) form. It usually crystallizes in tetrahydrated form.

This product promotes triggering of the precipitation of the natural calcium tartrate in wine by means of a seeding technique.

  1. Labelling

The label should indicate product concentration, even when used in mixtures, as well as its safety and storage conditions.

  1. Centesimal Composition

Tartaric acid

57.7

Calcium 

15.4

Water

27.9

  1. Properties

Fine, crystalline powder with a white or off-white color. Tasteless.  Melting point is 270 °C.

 

  1. Solubility

 

Water at 20 °C

0.525 g/l

Alcohol, 95% by vol.

0.15 g/l

Ethyl ether

0.01 g/l

  1. Tests

6.1.     Rotatory Power

Dissolve 1 g of the substance in 1l of 1 M hydrochloric acid.  After it has completely dissolved, it gives:

Rotatory power is sensitive to slight variations in pH.

6.2.     pH in Saturate Solution

  • Add 1 g of the product to 100 ml of distilled water.
  • After shaking for one hour and allowing the precipitate to resettle (15 minutes), an increase in pH of between 1.5 and 2.5 pH units should be observed.

6.3.     Desiccation Loss

  • Desiccation loss is determined up to constant weight in precisely-weighed sample of about 1 g.
  • At a temperature of between 100 and 105 °C, weight loss should be less than or equal to 2.5 pp 100.

6.4.     Preparing the Solution for Tests

Dissolve a sample precisely weight to about 1 g in 100 ml of 1 M hydrochloric acid.

6.5.     Sulfates

  • Take 10 ml of the test solution (Par. 6.4) and add to it 1 ml of 10 pp 100 barium chloride solution (R).
  • After homogenization, let sit after 15 minutes.
  • No clouding should occur.
  • If clouding does occur, it should be less intense than that in a control prepared using the method indicated in the Annex.  (Sulfate content, expressed in terms of sulfuric acid, should be less than 1 g/kg).

6.6.     Heavy Metals

Add 0.5 ml of concentrated ammonium hydroxide (R), 2 ml of pH 3.5 buffer solution (R) and 1.2 ml of thioacetamide reagent (R) to 10 ml of the test solution prepared under paragraph 6.4.  (Heavy metal content, expressed in terms of lead, should be less than 10 mg/kg).

6.7.     Lead

Using the method described in the Compendium, quantify lead analytically in the test solution prepared according to Par. 6.4. (Lead content should be less than 5 mg/kg).

6.8.     Mercury

Using the method described in the Annex, quantify mercury analytically in the test solution prepared according to Par. 6.4. (Mercury content should be less than 1 mg/kg).

6.9.     Arsenic

Using the method described in the Annex, quantify arsenic analytically in the test solution prepared according to Par. 6.4.

(Arsenic content should be less than 3 mg/kg).

6.10. Basic Residue Determination

  • Dissolve a sample, p, of tetrahydric calcium tartrate weighed precisely at about 0.5 g in 25 ml of 1 M hydrochloric acid solution (R).
  • Bring to boiling under reflux and allow to cool.
  • Titrate the excess acid  using 1 M sodium hydroxide solution (R) and in the presence of methyl red (R). Let  n be the quantity in millimeters of  the 1 M sodium hydroxide solution used. 1 ml of 1 M hydrochloric acid corresponds to 0.05005 g of calcium carbonate.
  • The content in parts per 100 of calcium carbonate is:

The products used in winemaking should contain a maximum of 3 pp 100 basic residues expressed in terms of calcium carbonate.

  1. Storage

Calcium tartrate should be stored away from moisture in hermetically-sealed containers.

Calcium sulfate

COEI-1-CALSUL Calcium sulfate

Ca x 2 O (Dihydrate)

CAS NUMBER 10101-41-4

  1. Objective and scope of application

This product is used for must acidification in the production of liqueur wines. Calcium sulfate added reacts with tartrate ions of the must producing insoluble calcium tartrate and releasing ion sulfate in the must. These facts originate modifications in ions equilibria that liberates proton ions and reduces the pH without increasing the titratable acidity.

  1. Labelling

The label should indicate the nature of calcium sulfate, batch number and the storage and safety requirements.

 

  1. Stoichiometric composition

CaSO4

79.1 %

H2O

20.9 %

  1. Properties

Calcium sulfate dihydrate exists as a white amorphous powder. Not to be confused with the anhydrous form which is very hygroscopic and sets in contact with must.

 

  1. Solubility

Slightly soluble in water and soluble in hydrochloric, sulphuric and nitric acid solutions.

 

  1. Tests

 

6.1. Desiccation losses

Free water: Weigh 50 g of calcium sulphate in a dish. Place it in an oven at 40 ºC until constant weight. Weight loss should not exceed 2 %.

Free and bonded water: Place another sample in an oven at 200 º C during 4 h. Total weight loss should not exceed 23 %.

 

6.2. Preparing the Solution for Tests

Weigh 10 g of calcium sulphate. In a 500 ml erlenmeyer flask which can be hermetically sealed, add 200 ml of tartaric acid solution at 5 g/L per litre and bring to pH 3 with HCl 0.1 N. Put this in a magnetic mixer, sprinkle gently the calcium sulphate and mix for 1 hour at a temperature of 20 2°C. Allow to settle and filter by eliminating the first 50 ml of filtrate. Collect at least 100 ml of clear liquid.

 

6.3. Lead

Using the technique described in the Compendium, analyse quantitatively the lead in the solution prepared for testing (Par. 6.2). Lead content in calcium sulfate should be less than 2 mg/kg.

 

6.4. Mercury

Using the technique described in the Compendium, analyse quantitatively the mercury in the solution prepared for testing (Par. 6.2). Mercury content in calcium sulfate should be less than 1 mg/kg.

 

6.5. Arsenic

Using the technique described in the Compendium, analyse quantitatively the arsenic in the solution prepared for testing (Par. 6.2). Arsenic content in calcium sulfate should be less than 3 mg/kg.

 

6.6. Iron

Using the technique described in the Compendium, analyse quantitatively the iron in the solution prepared for testing (Par. 6.2). Iron content should be less than 200 mg/kg.

 

6.7. Quantitative Analysis

  • Any method of analysis included in the Compendium could be used. In the case of using the gravimetric method OIV-MA-AS321-05A, use the following procedure.
  • Weigh 250 milligrams of the sample dried at 40 ºC with a precision of 1 mg and dissolve it in 10 mL HCl 1M.
  • Take 5 mL of this solution and add 0,5 mL of HCl 2 M and 1,5 mL of a solution of BaCl2 400 g/L. Stir with a glass stirrer; rinse the stirrer with a little distilled water and leave to stand for 5 min.
  • Centrifuge for 5 min at 3.000 rpm, then carefully decant the supernatant liquid.
  • Wash the barium sulfate precipitate as follows: add 10 mL hydrochloric acid 2 M, place the precipitate in suspension and centrifuge for 5 min at 3.000 rpm, then carefully decant the supernatant liquid.
  • Repeat the washing procedure twice as before using 15 mL distilled water each time.
  • Quantitatively transfer the precipitate, with distilled water, into a tared platinum capsule and place over a water bath at 100°C until fully evaporated.
  • The dried precipitate is calcined several times briefly over a flame until a white residue is obtained. Leave to cool in a desiccator and weigh:

 

  1. Calculations

Content of calcium sulfate dihydrate in the product (%)=

  • Where p is the measured weight of BaSO4 in mg.

If other method of analysis of sulphates included in the Compendium is used to analyse the initial solution of calcium sulfate prepared for quantitative analysis:

Content of calcium sulfate dihydrate in the product (%)=

  • Where c is the concentration of sulfates in mg/L of K2SO4

The wine-making product must contain a minimum of 90 pp 100 calcium sulfate.

  1. Storage

Calcium sulfate should be stored in a dry place in hermetically sealed containers away from volatile elements it could adsorb.

Caramel

COEI-1-CARAME Caramel

N° SIN : 150

  1. Object, origin and field of application

Caramel can be found in liquid form or solid form ranging in colour from dark brown to black. Colouring wine in the stricto sensu is not allowed but caramel is used as a colouring agent in certain liquor wines, spirit beverages of vitivinicultural origin and wine-based beverages.

  1. Definitions

Caramel (or ordinary caramel) (Class I) (SIN: 150a)

  • Caramel (or ordinary caramel) is prepared by controlled heating of carbohydrates made up of glucose and fructose monomers and/or their respective polymers (for example, glucose syrup, saccharose and/or inverted sugars syrups). To favour caramelisation, acids, bases and salts excluding ammonium compounds can be used.

Caustic sulphite caramel (Class II) (SIN:150b)

  • Caustic sulphite caramel is prepared by controlled heating of carbohydrates as defined for ordinary caramel, with or without acids or bases, in the presence of sulphite compounds (sulphuric acid, potassium sulphite, potassium hydrogen sulphite, sodium sulphite and sodium hydrogen sulphite). No ammonium compounds are used.

Ammonia caramel (Class III) (SIN:150c)

  • Ammonia caramel is prepared by controlled heating of carbohydrates as defined for ordinary caramel, with or without acids or bases, in the presence of ammonium compounds (ammonium hydroxide, ammonium carbonate, ammonium hydrogen carbonate, and ammonium phosphate). No sulphite compounds are used.

Ammonium sulphite caramel (Class IV) (SIN: 150d)

  • Ammonia sulphite caramel is prepared by controlled heating of carbohydrates as defined for ordinary caramel, with or without acids or bases, in the presence of sulphite and ammonium compounds (sulphuric acid, potassium sulphite, potassium hydrogen sulphite, sodium sulphite, sodium hydrogen sulphite, ammonium hydroxide, ammonium carbonate, ammonium hydrogen carbonate, ammonium phosphate, ammonium sulphate, ammonium sulphite and ammonium hydrogen sulphite.
  1. Labelling

The concentration of the product and whether it was mixed, must be indicated on the label in addition to the storage conditions.

  1. Test trials

4.1.    Intensity of the colouring

The intensity of the colouring is defined as the absorbance of a liquid solution of 0.1% (m/v) concentrated caramel measured in a 1 cm space of optical pathway with light waves of 610 nm.

4.2.    Total Nitrogen

Apply the method described in Chapter II of the International Oenological Codex to 2 g of exactly measured caramel.

4.3.    Preparation of the solution for the test trials

  • Place 2 g of caramel in a capsule; put in heat chamber at 105°C for 4 hours than incinerate carefully without going beyond 550°C.
  • Take the cinders and put in 10 ml of 10% hydrochloric acid (R). Heat a little and transfer to a graduated 50 ml flask and rinse the capsule with water and fill up to the indicator.

4.4.    Heavy metals

  • Take 10 ml of the solution prepared for the trial tests as in point 4.3, and add 2 ml of 3.5 pH buffer solution (R) and 1.2 ml of thioacetamide reagent (R).
  • If the solution turns brown, it must be less brown than the control sample, as indicated in Chapter II of the International Oenological Codex.

4.5.    Lead

Using the solution for test trials as prepared in the point 4.3, measure out the lead as indicated in Chapter II of the International Oenological Codex. Please refer to point 5 for maximum contents.

4.6.    Mercury

Measure out the mercury using the method described in Chapter II of the International Oenological Codex.

Please refer to point 5 for maximum contents.

4.7.    Cadmium

  • Test solution prepared according to point 4.3;
  • Measure out the cadmium using the method described in Chapter II of the International Oenological Codex.

Please refer to point 5 for maximum contents.

4.8.    Arsenic

  • Test solution prepared according to point 4.3;
  • Measure out the arsenic using the method described in Chapter II of the International Oenological Codex.

Please refer to point 5 for maximum contents.

4.9.    Colouring matter retained on DEAE cellulose

See method as described by JECFA published in the Compendium of food additive specifications, FAO Food and Nutrition Paper 52 Add. 8.

4.10. Colouring matter retained on phosphorylcellulose

See method as described by JECFA published in the Compendium of food additive specifications, FAO Food and Nutrition Paper 52 Add. 8.

4.11. 4‑Methylimidazole

See method as described by JECFA published in the Compendium of food additive specifications, FAO Food and Nutrition Paper 52 Add. 8.

4.12. 2‑Acetyl‑4‑tetrahydroxybutylimidazole

See method as described by JECFA published in the Compendium of food additive specifications, FAO Food and Nutrition Paper 52 Add. 8.

4.13. Total sulphur

See method as described by JECFA published in the Compendium of food additive specifications, FAO Food and Nutrition Paper 52 Add. 8.

4.14. Sulphur dioxide

The method used can be found in the O.I.V. Compendium of International Methods of Analysis of Wine and Musts.

  1. Particular specifications

5.1.    Ordinary caramel

Colouring matter retained on DEAE cellulose

Not more than 50%

Colouring matter retained on phosphorylcellulose

Not more than 50%

Colour intensity

0.01 – 0.12

Total nitrogen

Not more than 0.1%

Total sulphur

Not more than 0.3%

Arsenic

Not more than 1 mg/kg

Lead

Not more than 2 mg/kg

Mercury

Not more than 1 mg/kg

Cadmium

Not more than 1 mg/kg

Heavy metals (expressed in Pb)

Not more than 25 mg/kg

5.2.    Caustic sulphite caramel

Colouring matter retained on DEAE cellulose

Not more than 50%

Colour intensity

0.06 – 0.10

Total Nitrogen

Not more than 0.2%[1]

Total sulphur dioxide

Not more than 0.2% [2]

Total sulphur

1.3 – 2.5%[3]

Sulphur retained on DEAE cellulose

Over 40%

Percentage of optical colour density retained

on DEAE cellulose

19-34

OD 280/560 ratio

Over 50

Arsenic

Not more than 1 mg/kg

Lead

Not more than 2 mg/kg

Mercury

Not more than 1 mg/kg

Heavy metals (expressed in lead)

Not more than 25 mg/kg

5.3.    Ammonia caramel

Colouring matter retained on DEAE cellulose

Not more than 50%

Colour matter retained on phosphorylcellulose

Not more than 50%

Colour intensity

0.08 – 0.36

Ammoniac nitrogen

Not more than 0.4%[4]

4‑Methylimidazole

Not more than 250 mg/kg[5]

2‑Acetyl‑4‑tetrahydroxybutylimidazole

Not more than 10 mg/kg[6]

Total sulphur

Not more than 0.3%[7]

Total nitrogen

1.3 – 6.8%[8]

Percentage of optical colour density
retained on phosphorylcellulose

13-35

Arsenic

Not more than 1 mg/kg

Lead

Not more than 2 mg/kg

Mercury

Not more than 1 mg/kg

Cadmium

Not more than 1 mg/kg

Heavy metals (expressed in lead)

Not more than 25 mg/kg

5.4.    Ammonium sulphite caramel

Colouring matter retained on DEAE cellulose

Not more than 50%

Colour intensity

0.10 – 0.60

Ammoniac nitrogen

Not more than 2.6%[9]

Sulphur dioxide

Not more than 0.5%[10]

4‑Methylimidazole

Not more than 250 mg/kg[11]

Total nitrogen

0.5 – 7.5%[12]

Total sulphur

1.4 – 10%[13]

Nitrogen/sulphur precipitation by alcohol ratio

0.7 – 2.7

OD precipitation by alcohol ratio[14]

8-14

OD 280/560 ratio[15]

Not more than 50

Arsenic

Not more than 1 mg/kg

Lead

Not more than 2 mg/kg

Mercury

Not more than 1 mg/kg

Cadmium

Not more than 1 mg/kg

Heavy metals (expressed in lead)

Not more than 25 mg/kg

  1. Storage conditions

Caramel must be stored in a closed container.

  1. References
  • Directive 95/45/CE Journal officiel des Communautés européennes, L 226, 22 September 1995.
  • Compendium of food additive specifications, Addendum 8, FAO Food and Nutrition Paper 52 Add.8.
  • Joint FAO/WHO Expert Committee on Food Additives (JECFA) ISBN 92-5-104508-9.

[1] Expressed by the intensity of equivalent colouring; or compared to a product with a colour intensity of 0.1 unit of absorption.

[2] Expressed by the intensity of equivalent colouring; or compared to a product with a colour intensity of 0.1 unit of absorption.

[3] Expressed by the intensity of equivalent colouring; or compared to a product with a colour intensity of 0.1 unit of absorption.

[4] Expressed by the intensity of equivalent colouring; or compared to a product with a colour intensity of 0.1 unit of absorption.

[5] Expressed by the intensity of equivalent colouring; or compared to a product with a colour intensity of 0.1 unit of absorption

[6] Expressed by the intensity of equivalent colouring; or compared to a product with a colour intensity of 0.1 unit of absorption

[7] Expressed by the intensity of equivalent colouring; or compared to a product with a colour intensity of 0.1 unit of absorption

[8] Expressed by the intensity of equivalent colouring; or compared to a product with a colour intensity of 0.1 unit of absorption

[9] Expressed by the intensity of equivalent colouring; or compared to a product with a colour intensity of 0.1 unit of absorption.

[10] Expressed by the intensity of equivalent colouring; or compared to a product with a colour intensity of 0.1 unit of absorption.

[11] Expressed by the intensity of equivalent colouring; or compared to a product with a colour intensity of 0.1 unit of absorption.

[12] Expressed by the intensity of equivalent colouring; or compared to a product with a colour intensity of 0.1 unit of absorption.

[13] Expressed by the intensity of equivalent colouring; or compared to a product with a colour intensity of 0.1 unit of absorption.

[14] The optical densities of precipitation by alcohol is defined as the optical density of precipitation at 280 nm divided by the optical density at 560 nm (in a 1 cm space).

[15] The optical densities of precipitation by alcohol is defined as the optical density of precipitation at 280 nm divided by the optical density at 560 nm (in a 1 cm space).

Caseins

COEI-1-CASEIN Caseins (Lactic Casein or Caseina acids)

  1. Object, origin and field of application

Casein, a heteroprotein containing phosphorous, is found in milk in the state of calcium salt.

It is obtained by coagulating skim milk.

It is the fining agent indicated for the treatment of oxidations in wine. It can only be used in alkaline water with potassium carbonate or potassium hydrogenocarbonate.

Casein adsorbs polyphenols, in particular oxidised polyphenols.

  1. Labelling

The concentration of casein used for the preparation must be indicated on the label including in the case of a mixture, as well as the storage conditions.

  1. Characteristics

 

Casein is a yellowish white coloured powder. It is amorphous, odourless and insoluble in pure water and various organic solvents. It can have a slight lactic odour. In alkaline water or in saline solutions with alkaline reactions, it swells and produces a colloidal solution: 100 ml of alkaline water for 1 g of potassium hydroxide or sodium hydroxide, dissolve 10 g of casein in a water bath at 100°C. The solution diluted 20 times its volume in water is cloudy; it should be free of lumps.

The so-called soluble caseins are mixed with pure powder and/or potassium carbonate (maximum 20%), or potassium hydrogenocarbonate).

Caseins used in oenology are fit for human consumption.

  1. Identifying characteristics

4.1.     Casein doesn’t precipitate by heating its alkaline solution. This solution precipitates by acidification once the pH is less than 5.

4.2.     Casein ashes contain phosphates characterised by the nitromolybdic reagent (R).

  1. Test trials

 

Casein should have no flavour, nor abnormal odour (rotten, mouldy, putrid, etc.)

5.1.     Acidity

5.1.1.  Principle

Determining free acidity in casein by an acidobasic determination of an aqueous extract of the product.

5.1.2.  Reagents

  • Sodium hydroxide 0.1 M
  • Phenolphthalein, solution at 10 g/l in ethanol

5.1.3.  Procedure

Preliminary test:

  • Homogenise the product by shaking vigorously;
  • Put 50 g of the product on a strainer (metal mesh strainer 200 mm in diameter, nominal size of 500 µm for the opening with a receptacle (Standard ISO 3310/1);
  • If 50 g of the product passes through completely, use the product as it is;
  • If the 50 g of the product do not pass through, grind the product until 50 g do pass through.

During all these operations, avoid changing the water content of the product.

Preparation for the test trial solution:

  • Take approximately 10 g to the nearest 10 mg of the 50 g passed through the strainer, or m of this mass.
  • Put the mass m in a 250 ml conical flask.
  • Pour 200 ml of recently boiled distilled water brought to 60°C into the flask.
  • Shake the closed flask.
  • Allow to stand for 30 minutes in a water bath at 60 °C while shaking the flask every 10 minutes.
  • Filter.
  • The filtrate at 20°C must be clear.

Carrying out the test:

  • Take 100 ml of filtrate.
  • Place the test sample in a 250 ml conical flask.
  • Add 0.5 ml of phenolphthalein solution to the flask.
  • Titrate using 0.1 M sodium hydroxide solution.
  • Let V represent the volume used.

5.1.4.  Calculation

Free acidity in casein expressed in meq/l is equal to:

  • V is the volume in ml of sodium hydroxide used.
  • T is the exact mole fraction of the sodium hydroxide solution.
  • m is the mass density in g of the test trial sample.

Acidity expressed as lactic acid should be less than 1.6 g/l.

5.2.     pH

  • Shake 10 g of casein in 100 ml of water for a few minutes.
  • Decant; the pH of the solution should be less than or equal to 5 for pure casein.

5.3.     Loss by dessication

  • Determine the weight loss of 2 g of the test trial sample by drying to constant weight at 100°C-105°C.
  • Weight loss of casein must be less than 12%.

All the limits set below apply to dried products.

5.4.     Ashes

  • Incinerate the residue left in the weight loss determination by dessication, without exceeding 600 °C.
  • The rate of the ashes should be less than 3% for casein acid and less than 23% for the casein acid and potassium carbonate or potassium hydrogenocarbonate mixture.

5.5.     Preparation of test trial solution

  • After determining the weight of the ashes, dissolve them in 2 ml of concentrated hydrochloric acid (R) and 10 ml of water.
  • Heat to dissolve and add water until reaching a volume equal to 25 times the weight of dried casein. 1 ml of this solution contains 0.04 g of dried casein mineral matters.

5.6.     Iron

Take 10 ml of the test trial solution (5.5), and add 1 ml of concentrated hydrochloric acid (R), 3 drops of hydrogen peroxide solution at 3 volumes(R) and 2 ml of potassium thiocyanate solution at 5% (R).

If a red colouration appears, it must be lighter than the control prepared with 8 ml of iron solution (III) at 0.01 g of iron per litre (R), 2 ml of water and the same volumes of concentrated hydrochloric acid (R) and potassium thiocyanate solution at 5% (R).

Iron content should be less than 200 mg/kg.

This determination can also be carried out by atomic absorption spectrophotometry.

5.7.     Lead

On the test trial solution (5.5), determine the lead according to the method described in Chapter II of the International Oenological Codex.

Lead content should be less than 5 mg/kg.

5.8.     Cadmium

On the test trial solution (5.5), determine the cadmium according to the method described in Chapter II of the International Oenological Codex.

Cadmium content should be less than 1 mg/kg.

5.9.     Mercury

Determine the mercury according to the method described in Chapter II of the International Oenological Codex.

Mercury content should be less than 1 mg/kg.

5.10. Arsenic

On the test trial solution (5.5), determine the arsenic according to the method described in Chapter II of the International Oenological Codex.

Arsenic content should be less than 3 mg/kg.

5.11. Total nitrogen

Introduce approximately 0.20 g of casein precisely weighed in a mineralisation flask with 15 ml of concentrated sulphuric acid (R) and 2 g of mineralisation catalyst (R) and continue the operation according to the method in chapter II of the International Oenological Codex.

Total nitrogen content must be more than 13%.

5.12. Proteins

Protein content should not be less than 82% of weight (total nitrogen 6.38).

5.13. Fat content

Determine the fat content using the gravimetric Schmid-Bondzynski-Ratslaff method (standard ISO 5543).

Fat content should be less than 2%.

5.14. Bacteriological monitoring

Proceed as indicated in chapter II of the International Oenological Codex.

Limit: total viable microorganisms: less than 3 x 104  CFU/g.

5.15. Coliforms

Proceed with counting according to the method in chapter II of the International Oenological Codex.

Absence must be checked on a sample of 25 g.

5.16. Staphylococci

Proceed with counting according to the method in chapter II of the International Oenological Codex.

The number of staphylococci (ß-hemolytiques positive coagulase) must be less than or equal to 1 per g.

5.17. Escherichia Coli

Proceed with counting according to the method in chapter II of the International Oenological Codex.

Absence must be checked on a sample of 1 g.

5.18. Salmonella

Proceed with counting according to the method in chapter II of the International Oenological Codex.

The number of salmonella should be less than 1 per 100 g.

5.19. Yeasts

Proceed with counting according to the method in chapter II of the International Oenological Codex.

Content limit: 103 CFU/g of preparation.

5.20. Lactic bacteria

Proceed with counting according to the method in chapter II of the International Oenological Codex.

Content limit: 102 CFU/g of preparation.

5.21. Lactobacillus sp.

Content limit: 10 CFU/g of preparation.

5.22. Pediococcus sp.[2]

Content limit: absence in a 10 g preparation sample.

5.23. Acetic bacteria

Proceed with counting according to the method in chapter II of the International Oenological Codex.

Content limit: 103 CFU/g of preparation

5.24. Mould

Proceed with counting according to the method in chapter II of the International Oenological Codex.

Content limit: 103 CFU/g of preparation

  1. Storage

Casein must be stored in watertight bags between 5°C and 20°C with relative humidity less than 65%. Its shelf life is 24 months.

  1. References
  • Standard ISO 5543.

 Method to be defined later on

[2] Method to be defined later on

Cellulose

COEI-1-CELLUL Cellulose

(

INS N°: 460

  1. Object, origin and field of application

Cellulose is obtained from mechanical processing and purification from an alpha-cellulose, which comes directly from vegetable fibres. Its molecular weight is 1.5. Dalton. Cellulose fibre is used for its absorbency traits, mainly for the filtration of wine.

  1. Labelling

The concentration of the product and whether it was mixed, must be indicated on the label in addition to the change.

  1. Characteristics

Cellulose is a white odourless, flavourless, fibre. It is insoluble in water.

  1. Test trials

4.1.     pH

  • Mix 5g of cellulose in 40 ml of water free of carbon dioxide, for 20 minutes.
  • Centrifuge.
  • The pH of the supernatant will be between 5.0 and 7.5.

4.2.     Humidity and volatile matter

  • Put 5 g of cellulose in an incubator at 105°C for 3 hours.
  • Mass loss must not exceed 8%.

 

All of the maximum limits set below refer to the dried product.

4.3.     Starch

  • Add 90 ml of water (R) to 10 g of microcrystalline cellulose and boil for 5 minutes.
  • Filter when hot. Cool and add 0.1 ml of 0.05 Miodine to the filtrate.
  • A blue colour should not appear.

 

4.4.     Ashes

  • Incinerate at 600 25°C the residue obtained according to point 4.2, for 4 hours.
  • The weight of the ashes should not exceed 2%.

4.5.     Preparation of the test solution

  • After weighing, dissolve ashes in 2 ml of concentrated hydrochloric acid (R) and 10 ml of water (R).
  • Heat in order to dissolve and fill the water up to 50 ml. (R).

4.6.     Iron

Determine iron using an atomic absorption spectrophotometer (following the method described in Chapter II on the test solution (4.5).

Iron content must be less than 100 mg/kg.

4.7.     Lead

Measure out lead following the method described in Chapter II on the test solution (4.5). Lead content must be less than 5 mg/kg.

4.8.     Mercury

Measure out mercury following the method described in Chapter II on the test solution (4.5).

Mercury content must be less than 1 mg/kg.

4.9.     Cadmium

Measure out cadmium as described in Chapter II on the test solution (4.5).

Cadmium content must be less than 1 mg/kg.

4.10. Arsenic

Measure out arsenic following the method described in Chapter II on the test solution (4.5).

Arsenic content must be less than 2 mg/kg.

4.11. Calcium

Determine calcium using an atomic absorption spectrophotometer (see method described in Chapter II on the test solution (4.5). Calcium content must be less than 500 mg/kg.

4.12. Water soluble substances

Evaporate the aliquot part of the supernatant obtained when measuring the pH level at point 4.1, in an incubator at 105°C for 3 hours. The soluble substance content should not exceed 0.25%.

  1. Storing conditions

Cellulose should be kept in a well-ventilated place in sealed packages away from volatile substances susceptible of being adsorbed.

Cellulose powdered

POWDERED CELLULOSE

(C12H20O10)n
INS No.: 460 (ii)

CAS No.: 9004-34-6

OIV-OENO 681-2022

1. Object, origin and scope of application

Powdered cellulose is cellulose of food-grade quality. Cellulose is a linear glucose homopolymer composed of glucopyranose units linked by β-1,4-glycosidic bonds; its degree of polymerisation (DP) is dependent on the origin of the cellulosic material.

Powdered cellulose is a non-modified, purified cellulose, obtained by the mechanical disintegration of alpha-cellulose procured in pulp form from fibrous plant material.

Powdered cellulose plays a “support” role in clarified fermentation media; it allows for improved “degassing” of carbon dioxide at the start of alcoholic fermentation and thus shortens the latency phase.  It increases the fermentability of must.

2. Labelling

The following should be mentioned on the label:

- the identification of the cellulose and its use in food,

- the concentration of the product, including in the case of a mixture,

- safety and storage conditions

- the batch no.,

- the expiry date.

3. Characteristics

Powdered cellulose comes in the form of flakes or very fine fibres, and is whitish in colour, odourless and flavourless.

4. Test limits and methods

4.1 Identification

Place approx. 10 mg powdered cellulose on a watch glass and disperse into 2 mL iodinated zinc chloride solution (R). The solution will turn a blue-purple colour.

4.2 Solubility

Powdered cellulose is insoluble in water, ethanol, ether and diluted acids, and slightly soluble in sodium hydroxide solution.

4.3 Purity

The powdered cellulose content should not be less than 92%.

4.4 Size of fine particles

The size of fine particles should not be less than 5 µm; the number of particles smaller than 5µm should not exceed 10%.

4.5 pH

Mix approx. 10 g dry cellulose in 90 mL water free of carbon dioxide for 60 min. Centrifuge.
The pH of the supernatant liquid should be between 5.0 and 7.5.

4.6 Water-soluble substances

Mix around 6 g of sample, dried beforehand, with 90 mL water that has recently been boiled then cooled. Leave to rest for 10 min. Filter using a membrane with porosity of 3 µm, throw away the first 10 mL of filtrate and pass the filtrate through the same filter a second time if necessary to obtain a clear filtrate. Evaporate a 15-mL portion of filtrate to dryness in a tared evaporating dish over a water bath, and dry to 105 °C for 1 h. Weigh the dish containing the dry residue. Less than 15 mg of residue should be obtained.

4.7 Detection of starch

Add 90 mL demineralised water (R) to 10 g powdered cellulose and boil for 5 min. Filter while hot with a 25-µm membrane filter. Cool and add 0.1 mL 0.05 M iodine solution to the filtrate. No blue colouration should appear. With very fine grains, a light blue colour may be observed after the addition of the iodine solution but will disappear after 30 minutes.

4.8 Loss on drying

Place 1 g powdered cellulose in a tared dish in an oven at 100-105 °C for 3 hours. The loss on drying should not exceed 7.0%.

4.9 Ashes

Incinerate the residue obtained in point 4.8 at 800 ± 25 °C for 4 hours.
The weight of the ashes should not be greater than 0.3%.

All of the limits set below relate to dry products.

5. Preparation of the test solution

After weighing, dissolve the ashes in 2 mL concentrated hydrochloric acid (R) and 10 mL water (R). Heat to activate dissolution and make up to 50 mL with water.

5.1 Iron

Determine the iron content of the solution prepared for testing purposes (5) by atomic absorption spectrophotometry according to the method described in Chapter II.
The iron content should be less than or equal to 10 mg/kg.

5.2 Lead

Determine the lead content of the solution prepared for testing purposes (5) according to the method described in Chapter II.
The lead content should be less than 2 mg/kg.

5.3 Mercury

Determine the mercury content of the solution prepared for testing purposes (5) according to the method described in Chapter II.
The mercury content should be less than 1 mg/kg.

5.4 Cadmium

Determine the cadmium content of the solution prepared for testing purposes (5) according to the method described in Chapter II.
The cadmium content should be less than 1 mg/kg.

5.5 Arsenic

Determine the arsenic content of the solution prepared for testing purposes (5) according to the method described in Chapter II.
The arsenic content should be less than 1 mg/kg.

6. Storage

Powdered cellulose should be stored in a well-ventilated place in airtight packaging, away from any volatile substances that it could adsorb.

Mycrocristalline cellulose

COEI-1-CELMIC Microcristlaline cellulose

INS N°: 460

  1. Object, origin and field of application

Microcrystalline cellulose is purified cellulose and is partially depolymerised. It comes from the treatment of alpha-cellulose mineral acids from plant fibres. Its molecular weight is approximately 36 000

Microcrystalline cellulose plays an important role in “supporting” very clarified fermentation as it increases the fermentability of the juices.

  1. Labelling

The concentration of the product must be mentioned on the label and if there is mixing as well as the method of preservation.

  1. Characteristics

 

Cellulose is found in microcrystalline powder form. white. odourless and tasteless. It is almost insoluble in water. acetone. ethanol. toluene. diluted acids and in 50 g/l sodium hydroxide solutions.

  1. Identification

4.1.    In a watch glass. put approximately 10 mg of microcrystalline cellulose and add 2 ml of zinc chloride iodated solution (R). The solution turns bluish purple.

4.2.    Degree of polymerisation

  • Put 1.300 g of  microcrystalline cellulose in a 125 ml conical flask. Add 25 ml of water (R) and 25 ml of 1M cupriethylenediamine hydroxide.
  • Immediately pass a nitrogen current. Close the flask and mix until completely dissolved.
  • For 7 ml of the solution into an appropriate glass capillary viscosimetric tube.

Time how long it takes between two lines on the viscosimeter and express the time measured in (t1). Calculate the kinematic viscosity V1 of the solution using the following formula:

In which k1 is the viscosimeter constant.

Take out an appropriate volume of 1M cupriethylenediamine hydroxide and dilute with the same volume of water. (R). Using an appropriate capillary viscosimeter. determine the time flow of this solution.

Calculate the kinematics viscosity V2 of the solvent using the following formula.

In which k2 is the viscosimeter constant.

Determine the relative viscosity ηrel  of the microcrystalline cellulose sample. using the following formula:

Determine the intrinsic viscosity []c by extrapolation. using the intrinsic viscosity table in Annex.

Calculate the degree of polymerisation P. using the formula:

In which m is the mass. in grams of the trial and b is the value obtained in the test trial " loss through drying " in %.

The degree of polymerisation is not over 350.

4.3.    pH

  • Shake for 20 minutes about 5 g of cellulose in 40 ml of water free of carbon dioxide.
  • Centrifuge.
  • The pH of the supernatant liquid must be between 5.0 and 7.5.

4.4.    Soluble substances in ether

  • Prepare a column of 10.0 g of microcrystalline cellulose in a glass tube with an inside diameter of approximately 20 mm.
  • Put 50 ml of ether free of peroxides (R). through the column and evaporate the eluate until bone dry.
  • The residue should not be above 5.0 mg (0.05%).

4.5.    Soluble substances in water

  • Mix 5.0 g of microcrystalline cellulose with 80 ml of water (R) for 10 mn.
  • Filter in a vacuum and collect the filtrate in a weighed vase.
  • Evaporate over a bath of 100° C water until bone dry and dry at 100-105°C for 1 hour.
  • The residue is not above 12.5 mg (0.25%).

4.6.    Starch

  • Add 90 ml of water (R) to 10 g microcrystalline cellulose. and boil for 5 mn.
  • Filter when hot.
  • Let cool and add 0.1 ml iodine 0.05 M to filtrate.
  • There is no blue colouring.

4.7.    Loss through drying

  • Put 1 g of cellulose in a mass capsule for 3 hours in an incubator at 100-105°C.
  • Loss through drying should not be more than 6.0%.

All limits set below refer to the dried product.

4.8.    Ashes

  • Incinerate at 600 ± 25°C the residue obtained in point 4.7. for 4 hours.
  • The mass of the ashes should not be more than 0.1%.

4.9.    Preparation of test solution

  • After weighing. dissolve the ashes in 2 ml of concentrated hydrochloric acid (R) and 10 ml of water (R).
  • Heat to activate the dissolution and fill up to 50 ml with water.

4.10. Iron

Determine iron with an atomic absorption spectrophotometer following the method described in Chapter II into the test solution (4.9).

Iron content must be less than less or equal to 10 mg/kg.

4.11. Lead

Determine the lead according to the method described in Chapter II. into the test solution (4.9).

Lead content must be less than 5 mg/kg.

4.12. Mercury

Determine the mercury according to the method described in Chapter II

Mercury content must be less than 1 mg/kg.

4.13. Cadmium

Determine the cadmium according to the method described in Chapter II. into the test solution (4.9).

Cadmium content must be less than 1 mg/kg.

4.14. Arsenic

Determine the arsenic according to the method described in Chapter II.

Arsenic content must be less than 1 mg/kg.

4.15. Calcium

Determine the calcium with an atomic absorption spectrophotometer. following the method described in Chapter II. into the test solution (4.9).

Calcium content must be less than 500 mg/kg.

5. Storing conditions

Cellulose must be stored in a well-ventilated place in sealed packages away from volatile substances which it might adsorb.

Table of instrinsic viscosity

Intrinsic viscosity. [η]c. according to value of relative viscosity.. ηrel

[η]c

rel

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

1.1

0.098

0.106

0.115

0.125

0.134

0.143

0.152

0.161

0.170

0.180

1.2

0.189

0.198

0.207

0.216

0.225

0.233

0.242

0.250

0.259

0.268

1.3

0.276

0.285

0.293

0.302

0.310

0.318

0.326

0.334

0.342

0.350

1.4

0.358

0.367

0.375

0.383

0.391

0.399

0.407

0.414

0.422

0.430

1.5

0.437

0.445

0.453

0.460

0.468

0.476

0.484

0.491

0.499

0.507

1.6

0.515

0.522

0.529

0.536

0.544

0.551

0.558

0.566

0.573

0.580

1.7

0.587

0.595

0.602

0.608

0.615

0.622

0.629

0.636

0.642

0.649

1.8

0.656

0.663

0.670

0.677

0.683

0.690

0.697

0.704

0.710

0.717

1.9

0.723

0.730

0.736

0.743

0.749

0.756

0.762

0.769

0.775

0.782

2.0

0.788

0.795

0.802

0.809

0.815

0.821

0.827

0.833

0.840

0.846

2.1

0.852

0.858

0.864

0.870

0.876

0.882

0.888

0.894

0.900

0.906

2.2

0.912

0.918

0.924

0.929

0.935

0.94 1

0.948

0.953

0.959

0.965

2.3

0.971

0.976

0.983

0.988

0.994

1.000

1.006

1.011

1.017

1.022

2.4

1.028

1.033

1.039

1.044

1.050

1.056

1.061

1.067

1.072

1.078

2.5

1.083

1.089

1.094

1.100

1.105

1.111

1.116

1.121

1.126

1.131

2.6

1.137

1.142

1.147

1.153

1.158

1.163

1.169

1.174

1.179

1.184

2.7

1.190

1.195

1.200

1.205

1.210

1.215

1.220

1.225

1.230

1.235

2.8

1.240

1.245

1.250

1.255

1.260

1.265

1.270

1.275

1.280

1.285

2.9

1.290

1.295

1.300

1.305

1.310

1.314

1.319

1.324

1.329

1.333

3.0

1.338

1.343

1.348

1.352

1.357

1.362

1.367

1.371

1.376

1.381

3.1

1.386

1.390

1.395

1.400

1.405

1.409

1.414

1.418

1.423

1.427

3.2

1.432

1.436

1.441

1.446

1.450

1.455

1.459

1.464

1.468

1.473

3.3

1.477

1.482

1.486

1.491

1.496

1.500

1.504

1.508

1.513

1.517

3.4

1.521

1.525

1.529

1.533

1.537

1.542

1.546

1.550

1.554

1.558

3.5

1.562

1.566

1.570

1.575

1.579

1.583

1.587

1.591

1.595

1.600

3.6

1;604

1.608

1.612

1.617

1.621

1.625

1.629

1.633

1.637

1.642

3.7

1.646

1.650

1.654

1.658

1.662

1.666

1.671

1.675

1.679

1.683

3.8

1.687

1.691

1.695

1.700

1.704

1.708

1.712

1.715

1.719

1.723

3.9

1.727

1.731

1.735

1.739

1.742

1.746

1.750

1.754

1.758

1.762

4.0

1.765

1.769

1.773

1.777

1.781

1.785

1.789

1.792

1.796

1.800

4.1

1.804

1.808

1.811

1.815

1.819

1.822

1.826

1.830

1.833

1.837

4.2

1.841

1.845

1.848

1.852

1.856

1.859

1.863

1.867

1.870

1.874

4.3

1.878

1.882

1.885

1.889

1.893

1.896

1.900

1.904

1.907

1.911

4.4

1.914

1.918

1.921

1.925

1.929

1.932

1.936

1.939

1.943

1.946

4.5

1.950

1.954

1.957

1.961

1.964

1.968

1.971

1.975

1.979

1.982

4.6

1.986

1.989

1.993

1.996

2.000

2.003

2.007

2.010

2.013

2.017

4.7

2.020

2.023

2.027

2.030

2.033

2.037

2.040

2.043

2.047

2.050

4.8

2.053

2.057

2.060

2.063

2.067

2.070

2.073

2.077

2.080

2.083

4.9

2.087

2.090

2.093

2.097

2.100

2.103

2.107

2.110

2.113

2.116

5.0

2.119

2.122

2.125

2.129

2.132

2.135

2.139

2.142

2.145

2.148

5.1

2.151

2.154

2.158

2.160

2.164

2.167

2.170

2.173

2.176

2.180

5.2

2.183

2.186

2.190

2.192

2.195

2.197

2.200

2.203

2.206

2.209

5.3

2.212

2.215

2.218

2.221

2.224

2.227

2.230

2.233

2.236

2.240

5.4

2.243

2.246

2.249

2.252

2.255

2.258

2.261

2.264

2.267

2.270

5.5

2.273

2.276

2.279

2.282

2.285

2.288

2.291

2.294

2.297

2.300

5.6

2.303

2.306

2.309

2.312

2.315

2.318

2.320

2.324

2.326

2.329

5.7

2.332

2.335

2.338

2.341

2.344

2.347

2.350

2.353

2.355

2.358

5.8

2.361

2.364

2.367

2.370

2.373

2.376

2.379

2.382

2.384

2.387

5.9

2.390

2.393

2.396

2.400

2.403

2.405

2.408

2.411

2.414

2.417

6.0

2.419

2.422

2.425

2.428

2.431

2.433

2.436

2.439

2.442

2.444

6.1

2.447

2.450

2.453

2.456

2.458

2.461

2.464

2.467

2.470

2.472

6.2

2.475

2.478

2.481

2.483

2.486

2.489

2.492

2.494

2.497

2.500

6.3

2.503

2.505

2.508

2.511 

2.513

2.516

2.518

2.52 1

2.524

2.526

6.4

2.529

2.532

2.534

2.537

2.540

2.542

2.545

2.547

2.550

2.553

6.5

2.555

2.558

2.561

2.563

2.566

2.568

2.571

2.574

2.576

2.579

6.6

2.581

2.584

2.587

2.590

2.592

2.595

2.597

2.600

2.603

2.605

6.7

2.608

2.610

2.613

2.615

2.618

2.620

2.623

2.625

2.627

2.630

6.8

2.633

2.635

2.637

2.640

2.643

2.645

2.648

2.650

2.653

2.655

6.9

2.658

2.660

2.663

2.665

2.668

2.670

2.673

2.675

2.678

2.680

7.0

2.683

2.685

2.687

2.690

2.693

2.695

2.698

2.700

2.702

2.705

7.1

2.707

2.710

2.712

2.714

2.717

2.719

2.721

2.724

2.726

2.729

7.2

2.731

2.733

2.736

2.738

2.740

2.743

2.745

2.748

2.750

2.752

7.3

2.755

2.757

2.760

2.762

2.764

2.767

2.769

2.771

2.774

2.776

7.4

2.779

2.781

2.783

2.786

2.788

2.790

2.793

2.795

2.798

2.800

7.5

2.802

2.805

2.807

2.809

2.812

2.814

2.816

2.819

2.821

2.823

7.6

2.826

2.828

2.830

2.833

2.835

2.837

2.840

2.842

2.844

2.847

7.7

2.849

2.851

2.854

2.856

2.858

2.860

2.863

2.865

2.868

2.870

7.8

2.873

2.875

2.877

2.879

2.881

2.884

2.887

2.889

2.891

2.893

7.9

2.895

2.898

2.900

2.902

2.905

2.907

2.909

2.911

2.913

2.915

8.0

2.918

2.920

2.922

2.924

2.926

2.928

2.931

2.933

2.935

2.937

8.1

2.939

2.942

2.944

2.946

2.948

2.950

2.952

2.955

2.957

2.959

8.2

2.961

2.963

2.966

2.968

2.970

2.972

2.974

2.976

2.979

2.981

8.3

2.983

2.985

2.987

2.990

2.992

2.994

2.996

2.998

3.000

3.002

8.4

3.004

3.006

3.008

3.010

3.012

3.015

3.017

3.019

3.021

3.023

8.5

3.025

3.027

3.029

3.031

3.033

3.035

3.037

3.040

3.042

3.044

8.6

3.046

3.048

3.050

3.052

3.054

3.056

3.058

3.060

3.062

3.064

8.7

3.067

3.069

3.071

3.073

3.075

3.077

3.079

3.081

3.083

3.085

8.8

3.087

3.089

3.092

3.094

3.096

3.098

3.100

3.102

3.104

3.106

8.9

3.108

3.110

3.112

3.114

3.116

3.118

3.120

3.122

3.124

3.126

9.0

3.128

3.130

3.132

3.134

3.136

3.138

3.140

3.142

3.144

3.146

9.1

3.148

3.150

3.152

3.154

3.156

3.158

3.160

3.162

3.164

3.166

9.2

3.168

3.170

3.172

3.174

3.176

3.178

3.180

3.182

3.184

3.186

9.3

3.188

3.190

3.192

3.194

3.196

3.198

3.200

3.202

3.204

3.206

9.4

3.208

3.210

3.212

3.214

3.215

3.217

3.219

3.221

3.223

3.225

9.5

3.227

3.229

3.231

3.233

3.235

3.237

3.239

3.241

3.242

3.244

9.6

3.246

3.248

3.250

3.252

3.254

3.256

3.258

3.260

3.262

3.264

9.7

3.266

3.268

3.269

3.271

3.273

3.275

3.277

3.279

3.281

3.283

9.8

3.285

3.287

3.289

3.291

3.293

3.295

3.297

3.298

3.300

3.302

9.9

3.304

3.305

3.307

3.309

3.311

3.313

3.316

3.318

3.320

3.321

10

3.32

3.34

3.36

3.37

3.39

3.41

3.43

3.45

3.46

3.48

11

3.50

3.52

3.53

3.55

3.56

3.58

3.60

3.61

3.63

3.64

12

3.66

3.68

3.69

3.71

3.72

3.74

3.76

3.77

3.79

3.80

13

3.80

3.83

3.85

3.86

3.88

3.89

3.90

3.92

3.93

3.95

14

3.96

3.97

3.99

4.00

4.02

4.03

4.04

4.06

4.07

4.09

15

4.10

4.11

4.13

4.14

4.15

4.17

4.18

4.19

4.20

4.22

16

4.23

4.24

4.25

4.27

4.28

4.29

4.30

4.31

4.33

4.34

17

4.35

4.36

4.37

4.38

4.39

4.41

4.42

4.43

4.44

4.45

18

4.46

4.47

4.48

4.49

4.50

4.52

4.53

4.54

4.55

4.56

19

4.57

4.58

4.59

4.60

4.61

4.62

4.63

4.64

4.65

4.66

Carbon (oenological)

COEI-1-CHARBO Oenological carbon

INS N° :153

  1. Object, origin and field of application

Oenological carbon are of plant (generally wood) origin. In order to increase their adsorption properties, the carbon is subjected to activation either at a high temperature or a lower temperature in the presence of an acid, (generally phosphoric acid). Oenological carbon must not be activated with a metal-based catalyser like zinc chloride.

It is in the form of very fine and light black powder, or in granulated form.

There are humid preparations which can reduce dust accumulation. In this case, weight loss as described in 3.1 can reach 60%.

Carbon can be agglomerated with bentonite.

Carbon for oenological purposes is used to correct alterations due to fungus in addition to the colour of white musts from purple, spotted or oxidised grapes. The carbon can eliminate anthocyanins and oxidised or non-oxidised polyphenols in addition to polysaccharides. The carbon are used to correct the organoleptic characteristics of musts made from grapes altered by fungus.

Oenological carbon can also be used to reduce the presence of Ochratoxin A in musts, the musts during fermentation and in white wine.

Decolourising carbon has a relatively weak deodorising effect.

Absorption by carbon is not very selective and depends on its structure, porosity and specific surface area.

The limit concerning the use of carbons should be compliant with the prescriptions of the OIV International Code of Oenological Practices (expressed by weight of dry carbon).

  1. Labelling

The label should indicate the storage conditions, the expiration date for humid solutions, and a mention of whether there are existing regulations regarding the usage of the product and specify if it concerns decolourising or deodorising carbon.

  1. Test trials

3.1.    Loss with dessication

  • Put 5g of carbon in a silica capsule and heat to 100°C in an incubator.
  • After 3 hours of dessicating, weight loss should not be more than 20%.

All limits set for carbon refer to dry carbon weight.

3.2.    Ashes

  • Incinerate the previously obtained dry residue at 500°C-600°C.
  • These ashes should not be more than 10%.
  • Carbon agglomerated with bentonite should have ashes more than 10% and less than 30%.

3.3.    Soluble matter in acids

  • Boil 5 g of dried carbon with 20 ml of concentrated hydrochloric acid (R) and 100 ml of water.
  • Once cooled, filter using a fine filter or membrane.

Evaporate the filtrate and dry at 100°C–105°C. The soluble matter content in acids should not be more than 5%.

3.4.    Chlorides

  • Shake 0.067g of dried carbon and 20 ml of distilled water.
  • Filter.
  • Add 5 ml of diluted nitric acid (R) to 5 ml of filtrate.
  • Fill up to 20 ml and add 0.5 ml of silver nitrate solution at 5% (R).
  • Compare any opalescence or cloudiness to a prepared control sample as indicated in the annex. Other methods such as ionic chromatography can be used.
  • Chloride content should not be more than 3g/kg.

3.5.    Cyanides

  • Put a quantity of carbon containing 1 g of dried carbon with 10 ml of diluted sulphuric acid (R) in a 100 ml conical flask.
  • Adapt to the conical flask a pressure relief tube plunged into approximately 2 ml of saturated borax solution (R) in a test tube.
  • Distil and gather 2 to 3 ml of distillate.
  • Add 5 drops of potassium anhydrosulphite solution at 2% (R) and leave for 5 minutes.
  • Add 1 ml of iron sulphate solution (II) at 5% (R) and leave for 15 minutes.
  • Then add 2 drops of phenolphthalein (R). Use a saturated borax solution (R) to make the solution a little more alkaline.
  • Leave for 5 minutes.
  • Add 2 drops of iron sulphate (III) and ammonia solution at 10% (R) and 1 ml of concentrated hydrochloric acid (R).
  • No colouration nor blue precipitate should form.

3.6.    Polycyclic  aromatic hydrocarbons

Polycyclic aromatic hydrocarbons including benzoa]pyrene are extracted by hexane; the solvent is evaporated and the residue is taken by the methanoltetrahydrofuran mixture for HPLC analysis following the method described in chapter II.

Note: It is also possible to determine benzoa]pyrene by gas chromatography by using an apolar capillary column with detection by mass spectrometry following the method described in chapter II of the International Oenological Codex.

Benzoa]pyrene content should not be more than 10 μg/kg.

3.7.    Sulphides

  • Put a quantity of carbon containing 1 g of dried carbon with 10 ml of diluted hydrochloric acid and 10 ml of water in a 50 ml flask.
  • Distil and collect 5 ml of distillate in a test tube containing 5 ml of 1 M sodium hydroxide solution.
  • 0.5 ml of lead nitrate solution at 1 g per litre (R) is added to 1 ml of test trial solution.
  • There should be no brown colouring or black precipitate.
  • Sulphide content expressed in sulphur should not be more than 20 mg/kg.

3.8.    Preparation of test trial solution

  • Put a quantity of carbon corresponding to 2.5 g of dried carbon with 50 ml of a citric acid solution at 5 g a litre with a pH of 3 (R), in a conical flask with a wide opening that can be sealed.
  • Shake vigorously for 5 minutes and allow to stand at least 12 hours.
  • Filter through a fine filter or a membrane in order to obtain a clear solution.

3.9.    Iron

  • Add 5 ml of water, 1 ml of concentrated hydrochloric acid, 2 ml of 5% potassium thiocyanate solution (R) to 5 ml of test trial solution as prepared in point 3.8.
  • The colouration obtained should be lighter than the control sample prepared with 10 ml of iron salt solution (II) at 0.010 g of iron per litre (R), and 1 ml of concentrated hydrochloric acid (R), 2 ml of 5% potassium thiocyanate solution (R). Atomic absorption spectrophotometry can also be used.

Iron content should not be more than 200 mg/kg.

3.10. Lead

Determine the lead according to the method described in chapter II on the test trial solution prepared according to point 3.8.

Lead content should not be more than 2 mg/kg.

3.11. Mercury

Determine the mercury according to the method described in chapter II on the test trial solution prepared according to point 3.8.

Mercury content should not be more than 1 mg/kg.

3.12. Arsenic

Determine the arsenic according to the method described in chapter II on the test trial solution prepared according to point 3.8.

Arsenic content should not be more than 3 mg/kg.

3.13. Calcium

Determine the calcium according to the method described in chapter II on the test trial solution prepared according to point 3.8.

Calcium content should not be more than 10 g/kg.

3.14. Cadmium

Determine cadmium according to the method described in chapter II on the test trial solution prepared according to point 3.8.

Cadmium content should not be more than 1 mg/kg.

3.15. Zinc

Determine the zinc according to the method described in chapter II on the test trial solution prepared according to point 3.8.

Zinc content should not be more than 25 mg/kg.

3.16. Specific surface area

The specific surface area of a decolourising carbon must be between 600 and 2000 m2/g.

Methylene blue decolourisation is the method used. (Methylene blue indicator).

3.17. Methylene blue indicator

  • Prepare 4 conical flasks and place 0.1 g of carbon.
  • Add 10, 15, 17 and 20 ml of methylene blue solution at 1.2 g/l (absorbance at 620 nm is between 0.830 and 0.850).
  • After shaking for 5 minutes, filter through a slow filter and note the volume of the solution in the conical flask which underwent decolourisation.

Depending on the results, repeat this experiment with different volumes of solution.

Put the solution in a spectrophotometer at 664 nm with the absorbance value of 0.08 with an optical path of 1 cm.

The volume of the methylene blue test solution in ml just discoloured, represents the methylene blue indicator.

  1. Phenol index

 

4.1.    Introduction

When activated carbon is applied in the treatment of wine, the phenol index can be used to define a limit value over which the carbon is considered as a decolouriser and under which it is regarded as a deodoriser. The phenol index selected is the AWWA B600-90 index

4.2.    Principle:

AWWA phenol index: this index, expressed in g of carbon scaled to the dry weight per l of solution represents the carbon powder concentration required to decrease the phenol concentration of a solution from 200 mg/l to 20 mg/l.

 

4.3.    Description of the AWWA method: 

This index is determined using an adsorption isotherm based on at least 4 different weights of carbon put in contact with a phenol solution.

This isotherm represents the weight of phenol adsorbed in mg/l/g carbon, in relation to the residual phenol concentration in the solution, expressed in mg/l.

4.4.    Reagents

4.4.1.  Pure disodic hydrogenophosphate Na2HPO4 for analysis

4.4.2.  Distilled water

4.4.3.  Pure phosphoric Acid (H3PO4)

4.4.4.  Pure phenol

4.4.5.  Buffer solution A of disodic hydrogenophosphate with a pH of 6.5 at 104 g/l

In a 1-litre graduated flask, dissolve 104 g of disodic hydrogenophosphate (4.4.1) in 300 ml of hot water (4.4.2), add 14 ml of phosphoric acid (4.4.3) and make up to one litre. Homogenise. Check that the pH is 6.5 0.1

4.4.6.  Buffer solution B of disodic hydrogenophosphate with a pH of 6.5 at 10.4 g/l

In a 1-litre graduated flask, place 100 ml of buffer solution A at 104 g/l (4.4.5) and make up with water (4.4.2). Homogenise.

4.4.7.  Phenol solution with 1 g/l

In a 100-ml graduated flask, place 100 mg of phenol (4.4.4) and make up to 100 ml with water (4.4.2). Obtain complete dissolution by stirring.

4.4.8.  Calibration solutions of phenol with 20, 40, 60, 80, 100, and 120 mg/l

In a series of 100-ml graduated flasks, respectively place 2 ml, 4 ml, 6 ml, 8 ml, 10 ml, and 12 ml of the phenol solution with 1 g/l (4.4.7). Make up to 100 ml using buffer solution B (4.4.6).

4.4.9.  Phenol solutions with 200 mg/l

In a 1-litre flask, place 200 ml of the phenol solution at 1 g/l (4.4.7), add 100 ml of buffer solution A (4.4.5), make up to 1 l with water (4.4.2). Homogenise.

4.4.10.     Measuring the phenol index of oenological carbon powder

Note: The water content of the carbon must be known in order to scale the index to the dry carbon weight.

4.5.    Apparatus

4.5.1.  Laboratory glassware i.e.: graduated precision pipettes to measure small volumes, 100-ml and 1-l graduated flasks, funnels, and 300-ml conical bottles

4.5.2.  Filter paper

4.5.3.  Laboratory balance, precision to within 0.10 mg

4.5.4.  Spectrometer capable of operating in the ultraviolet spectrum and housing quartz tanks with an optical thickness of 1 cm.

4.5.5.  Laboratory shaker (it is not recommended to use a magnetic bar)

4.6.    Procedure

4.6.1.  Phenol calibration curve.

Measure the absorbance at 270 nm in tanks with an optical thickness of 1 cm (4.5.4) of each phenol solution with 20, 40, 60, 80, 100, and 120 mg/l (4.4.8). Calculate the straight regression line of the absorbance in relation to the phenol concentration.

Note:The blank is based on buffer solution B (4.4.6).

4.6.2.  Determine the residual phenol for each carbon (4.4.10)

In a series of 300-ml conical flasks, place 200 ml of phenol solution at 200 mg/l (4.4.9), then respectively 0.4, 0.5, 0.6 and 0.7 g of carbon; close the bottle.

For these 4 preparations, stir for 30 minutes (4.5.5) so that the carbon remains in suspension.

Filter on paper (4.5.2) the 4 samples containing the carbon and a blank (phenol solution with 200 mg/l (4.4.8) without carbon).

Measure the absorbance at 270 nm in tanks with an optical thickness of 1 cm (4.5.4) of each one of the filtered solutions.

Note 1 The blank is based on buffer solution B (4.4.6).

Note 2 At least one of the quantities of carbon must adsorb 90% of the phenol in the solution; if not, widen the carbon weight range.

4.7.    Calculations

4.7.1.  Determine the percentage of residual phenol in each filtrate for each activated carbon:

residual % = milligram per litre of residual phenol filtrate * 100/200 (milligram per litre of phenol in the test solution).  i.e. a = % residual phenol

4.7.2.  Determine the percentage of X (adsorbed phenol):

% of X = 100 -% residual in the filtrate. i.e. X = 100 – a

4.7.3.  The quantities of activated carbon for 200 ml of phenol solution are multiplied by 5 to obtain the quantities of activated carbon, i.e. M in grams per litre.

4.7.4.  Calculate the percentage of the value of X/M for each activated carbon.

4.7.5.  Plot the isotherm: percentage of residual normality of the filtrate on the X-axis (a) and the percentage of X/M on the Y-axis using 2x2 logarithmic paper; establish the straight regression line and determine the regression equation. It is also possible to calculate the regression using the logarithm for the values of a and X/M.

4.7.6.  Determine X/M at 10%; i.e. C (when the residual phenol concentration of the filtrate is 10%).

4.7.7.  Phenol index in grams per litre = 90/C * (100 -% of humidity/100); i.e. P

This formula refers to activated carbon without humidity.

4.7.8.  Limit values

A carbon is regarded as a deodouriser if its phenol index is lower than 3.5

4.7.9.  Examples

Standard cuve

Abs at 270 nm

Phenol mg/l

0.303

20

0.603

40

0.8777

60

1.3443

100

1.53

120

Calibration straight line for phenol titration

A1

g of carbon

% humidity

Dry weight

Abs

C phenol

 

0,25

1.31

0.2467

0.309

23

0,6255

1.31

0.6173

0.065

5

0,7136

1.31

0.7043

0.0454

3

0,7829

1.31

0.7726

0.0367

3

A1 Calculations

           

a

X

M

a

X/M

Log a

Log X/M

 

11.53

88.47

1.23

11.53

71.72

1.061829

1.855636

 

2.42

97.58

3.09

2.42

31.61

0.384605

1.499871

 

1.69

98.31

3.52

1.69

27.92

0.228747

1.445885

 

1.37

98.63

3.86

1.37

25.53

0.136357

1.407065

 
       

c

   

P

     

10.00

66.16

1

1.8206

1.3

Adsorption isotherm of carbon A1

A2

g of carbon

% Humidity

Dry weight

Abs

C phenol

 

0.4054

1.60

0.3989

0.9969

74

0.6012

1.60

0.5916

0.679

51

0.7914

1.60

0.7787

0.4972

37

0.9032

1.60

0.8887

0.4126

31

1.4040

1.60

1.3815

0.2654

20

A2 Calculations

a

X

M

a

X/M

Log a

Log X/M

 

37.18

62.82

1.99

37.18

31.49

1.570343

1.498241

 

25.33

74.67

2.96

25.33

25.25

1.403561

1.402199

 

18.54

81.46

3.89

18.54

20.92

1.268222

1.320569

 

15.39

84.61

4.44

15.39

19.04

1.187221

1.279687

 

9.90

90.10

6.91

9.90

13.04

0.995635

1.115409

 
       

c

   

P

     

10

13.70

1

1.1367

6.5

Adsorption isotherm of carbon A2

4.7.10.     Collaborative analysis: AWWA phenol indices in g/l

 

Lab 1

Lab 2

Lab 3

Lab 4

A1

1.7

1.53

1.8

1.3

A2

5.1

4.56

6.2

6.5

A3

1.3

1.29

1.8

1.4

A4

5.8

4.95

10.0

7

B1

11.4

7.18

10.6

7.6

B2

1.8

1.47

2.3

1.4

B3

49.4

21.97

18.0

17.5

B4

2.9

2.80

3.6

2.6

C1

1.9

1.69

2.3

1.8

C2

1.7

1.56

2.0

1.5

C3

5.4

4.71

6.2

4.9

C4

5.4

4.55

6.0

4.7

Reproducibility: 2.88 for the 5.86 general average SR = 1,03

  1. Determination of the decolourisation capacity of carbon

5.1.    Principle

Measuring the decolourisation of an oenocyanin solution with a precise amount of carbon under defined conditions.

5.2.    Apparatus:

Equipment:

5.2.1.  Precision balance in mg

5.2.2.  5.2.2 Magnetic stirrer

5.2.3.  Absorption spectrophotometer for OD to 420, 520 and 620 nm measures Glassware:

5.2.4.  250 ml cylindrical flask

5.2.5.  250 ml conical flask

5.2.6.  200 ml volumetric flask

5.2.7.  Chamber with a 1 mm optical path for an absorption spectrophotometer.

5.3.    Reagents

5.3.1.  Very pure demineralised water

5.3.2.  Crystallised acetic acid

5.3.3.  Tartaric acid

5.3.4.  Crystallised sodium acetate

5.3.5.  96% volume ethanol

5.3.6.  Oenocyanin powder

5.4.    Preparation of oenocyanin solution

5.4.1.  Pour approximately 150 ml of demineralised water (5.3.1) in a 250 ml cylindrical flask (5.2.4).

5.4.2.  Shake (5.2.2).

5.4.3.  Weigh 0.900 g 0.001 g of oenocynanin (5.3.6) and dissolve by adding small amounts while stirring in a vortex mixer.

5.4.4.  Weigh 1.400 g 0.01 g of tartaric acid (5.3.3) and pour into the cylindrical flask (5.2.4).

5.4.5.  Pour 0.8 ml of crystallised acetic acid (5.3.2) and 1.4 g of crystallised sodium acetate (5.3.4).

5.4.6.  Shake continuously until completely dissolved (5.2.2)

5.4.7.  Transfer to a 200 ml volumetric flask (5.2.6).

5.4.8.  Adjust to 200 ml with the rinsing water from the cylindrical flask of the 5.4 preparation.

5.4.9.  Transfer again into a 250 ml cylindrical flask (5.2.4).

5.4.10.     Shake (5.2.2).

5.4.11.     Centrifuge 150 ml of the solution for 10 minutes at 10,000 g place the supernatant in a cuvette with 1 mm optical path

5.4.12.     Measure the colour intensity of the spectrometer (5.2.3)

CI1=OD 420+ OD 520+ OD 620

CI1=

5.5.    Decolourisation by carbon

5.5.1.  Weigh 100 mg of dried carbon.

(Measure the humidity in order to define the exact dose of humid carbon to be used).

5.5.2.  Put the carbon in 100 ml of oenocyanin solution with colour intensity

CI1= 4

5.5.3.  Shake for 30 minutes (5.2.2).

5.5.4.  Allow to stand for 10 minutes and centrifuge 10 ml of this mixture for 10 minutes at 10,000 g.

5.5.5.  Measure the colour intensity with a spectrometer (5.2.3) under 1 mm of optical path:

CI2=OD 420+ OD 520+ OD 620

5.6.    Calculation of decolourisation capacity

The decolourisation capacity (DC):

DC=100 (CI1-CI2)/CI1

Carbon is considered as a ‘decolourising agent’ when DC is more than or equal to 40.

  1. Storage

Carbon cannot be stored in open bags because of its adsorption capacities. Oenological carbon must be stored in sealed packages away from volatile substances that it could adsorb.

Chitin-glucan

COEI-1-CHITGL Chitin-glucan

[]m - []n

CAS number Chitin: 1398-61-4

CAS number β-glucan: 9041-22-9

  1. Purpose, origin and scope

Chitin-glucan is of fungus origin and is a natural polymer, the main component of the cellular walls of Aspergillus niger. It is initially extracted and purified from the mycelium of Aspergillus niger. This fungal resource is a by-product of the citric acid produced for the food and pharmaceutical markets.

Chitin-glucan is composed of polysaccharides chitin (repeat units N-acetyl-D-glucosamine) and 1,3-ß-glucan (repeat unit D-glucose). The two polymers are covalently connected and form a three-dimensional network. The chitin/glucan ratio ranges from 25:75 to 60:40 (m/m).

It is used as a fining agent of musts during racking in order to reduce the colloid content and cloudiness.

It is also used for stabilising wines prior to bottling after alcoholic fermentation. This polymer has a stabilising capacity with respect to ferric breakages. It also helps eliminate undesirable compounds such as heavy metals (lead, cadmium), mycotoxins, etc.

  1. Synonyms

Poly(N-acetyl-D-glucosamine)-poly(D-glucose) and 1,3- β-glucan

  1. Labelling

The following information must be stated on the packaging label: fungal origin, product for oenological use, use and conservation conditions and use-by date.

  1. Characters

4.1.   Aspect

Chitin-glucan comes in the form of a white, odourless and flavourless powder. Chitin-glucan is almost completely insoluble in aqueous or organic medium.

4.2.   Purity and soluble residues

 

The purity of the product must be equal to or higher than 95 %.

Dissolve 5 g of chitin-glucan in 100 ml of bidistilled water and agitate for 2 minutes. Filter after cooling on a fine mesh filter or membrane.

Evaporate the filtrate and dry at 100-105 °C. The content of solubles should not be higher than 5 %.

  1. Tests

5.1.   Identification and chitin-glucan ratio

5.1.1.       Determination of the chitin-glucan ratio

The chitin/glucan ratio is determined using the 13C NMR spectrum in solid phase, by comparison with the spectrum of a pure chitin reference sample.

This method is detailed in appendix I.

 

5.2.   Loss during desiccation

In a glass cup, previously dried for 1 hour in an oven at 100-105 °C and cooled in a desiccator, place 10 g of the analyte. Allow to desiccate in the drying oven at 100-105 °C to constant mass. Weigh the dry residue amount after cooling in the desiccator.

The weight loss must be lower than 10 %.

 

Note: all the limits stated below are reported in dry weight except for the microbiological analyses

 

5.3.   Ashes

Incinerate without exceeding 600°C the residue left from the determination of the loss during desiccation as described in 5.2. Allow to calcine for 6 hours. Allow the crucible to cool in a desiccator and weigh.

The total ash content should not be higher than 3 %.

 

5.4.   Preparation of the test solution

Before determining the metals, the sample is dissolved by acid digestion (HNO3, H2O2 and HCl). Mineralisation is performed in a closed microwave system. The sample undergoes neither crushing nor drying before mineralisation.

The reagents used for the mineralisation of chitin-glucan are as follows: HNO3 (65 %) (Suprapur), HCl (37 %) (Suprapur), H2O2 (35 %). The 0.5 to 2 g sample of chitin-glucan is placed in a flask to which are added 25 ml of HNO3, 2 ml of HCl and 3 ml of H2O2. This is submitted to microwave digestion (Power of 60 % for 1 min, 30 % for 10 min, 15 % for 3 min, and 40 % for 15 min). The solution is diluted in a volumetric flask with bidistilled water to a final volume of 25.0 ml.

The metal contents can then be determined.

 

5.5.   Lead

Lead is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The lead content must be lower than 1 mg/kg.

It is also possible to achieve lead determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

5.6.   Mercury

Mercury is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The mercury content must be lower than 0.1 mg/kg.

It is also possible to achieve mercury determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

 

5.7.   Arsenic

Arsenic is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The arsenic content must be lower than 1 mg/kg.

It is also possible to achieve arsenic determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

5.8.   Cadmium

Cadmium is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The cadmium content must be lower than 1 mg/kg.

It is also possible to achieve cadmium determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

5.9.   Chromium

Chromium is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The chromium content must be lower than 10 mg/kg.

It is also possible to achieve chromium determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

5.10.         Zinc

Zinc is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The zinc content must be lower than 50 mg/kg.

It is also possible to achieve zinc determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

5.11.         Iron

Iron is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The iron content must be lower than 100 mg/kg.

It is also possible to achieve iron determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

5.12.         Copper

Copper is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The copper content must be lower than 30 mg/kg.

It is also possible to achieve copper determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

 

5.13.         Microbiological control

5.13.1.   Total bacteria count

The total bacteria count is performed according to the horizontal method by means of the colony count technique at 30 °C on the PCA medium described in appendix III.

Less than 1000 CFU/g of preparation.

It is also possible to carry out the enumeration as described in chapter II of the International Oenological Codex.

5.13.2.   Enterobacteria

The enumeration of Enterobacteria is carried out according to the horizontal method by means of the colony count technique at 30 °C described in appendix IV.

Less than 10 CFU/g of preparation.

5.13.3.   Salmonella

Carry out the enumeration as described in chapter II of the International Oenological Codex.

Absence checked on a 25 g sample.

5.13.4.   Coliform bacteria

Carry out the enumeration as described in chapter II of the International Oenological Codex.

Less than 100 CFU/g of preparation.

5.13.5.   Yeasts

The enumeration of yeasts is carried out according to the horizontal method by means of the colony count technique at 25 °C on the YGC medium described in appendix V.

Less than 100 CFU/g of preparation.

It is also possible to carry out the enumeration as described in chapter II of the International Oenological Codex.

5.13.6.   Moulds

The enumeration of moulds is carried out according to the horizontal method by means of the colony count technique at 25 °C on the YGC medium described in appendix VI.

Less than 100 CFU/g of preparation.

It is also possible to carry out the enumeration as described in chapter II of the International Oenological Codex.

  1. Ochratoxin A testing

Prepare an aqueous solution (distilled water) of chitin-glucan at 1 % and agitate for 1 hour, then carry out determination using the method described in the Compendium of International Methods of Analysis of Wine and Musts.

Less than 5 µg/kg.

  1. Storage

Keep container closed and store in a cool and dry place.

Appendix I: Determination of the chitin/glucan ratio

 

  1. Principle

 

This method consists in determining the chitin/glucan ratio using the 13C RMN spectrum in solid phase.

  1. Reagents and materials
    1.    Chitin glucan sample
    2.    Osmosis purified water
    3.    Hydrochloric acid 1 M
    4.    Pure ethanol
    5.    Pure chloroform
    6.    Pure methanol
    7.    Acetone
    8.    Standard laboratory material, pipettes, cylindrical glass vases, porosity filters 30 μm…
    9.    Rotary shaker
    10.          Laboratory centifuge
    11.          Conductimeter
    12.          Nuclear Magnetic resonance apparatus
  1. Sample preparation

 

Before the determination, samples are prepared according to a precise protocol as described below:

3.1.   Washing with HCl 1 M (2.3)

This step consists in mixing 2 g of chitin-glucan (2.1) and 40 ml of HCl 1 M in a tube flask.

This mixture is agitated for 30 min at 320 rpm then centrifuged at 4000 rpm for 10 min. The supernatant is eliminated.

This step is repeated once.

3.2.   Washing with osmosis purified water

This step consists in mixing the sediment from the previous step with 40 ml of osmosis purified water (2.2).

This mixture is centrifuged for 10 min at 4000 rpm. The supernatant is eliminated.

This step is repeated until the supernatant conductivity is lower than 100 μS/cm.

3.3.   Washing with ethanol

This step consists in mixing the sediment from the previous step with 40 ml of ethanol (2.4).

This mixture is centrifuged for 10 min at 4000 rpm. The supernatant is eliminated.

This step is repeated once.

3.4.   Washing with chloroform/methanol

This step consists in mixing the sediment from the previous step with 40 ml of a of 50/50, v/v of chloroform (2.5) and methanol (2.6) mixture.

This mixture is agitated for 30 min at 320 rpm then centrifuged at 4000 rpm for 10 min. The supernatant is eliminated.

This step is repeated once.

3.5.   Washing with acetone and drying

This step consists in mixing the sediment from the previous step with 40 ml of acetone (2.7).

This mixture is agitated for 30 min at 320 rpm then centrifuged at 4000 rpm for 10 min.

After centrifugation, pour the supernatant on a 30 μm filter, rinse the tube flask with acetone (2.7) and pour everything on the filter.

Place the material located on the filter in a crystallising dish and allow to dry.

After drying, the product is ready to be analysed by NMR.

  1. Procedure

 

The prepared samples are then analysed on the Brücker Avance DSX 400WB nuclear magnetic resonance instrument (or the equivalent).

The analysis conditions are as follows:

  • Magnetic field: 9.04 Tesla
  • Larmor frequency: 83 kHz
  • Time interval between 2 magnetic pulses: 5s
  • Time period during which the magnetic pulse is applied: 5,5ms
  • Number of magnetic pulse sequences: 3000
  1. Expression of the results

5.1.   The beta-glucan content is determined from the area of the four resonance bands.

5.2.   The results are expressed in mol %.

 

Appendix II : Metal determination by atomic emission spectroscopy

 

  1. Principle

 

This method consists in measuring atomic emission by an optical spectroscopy technique.

 

  1. Sample preparation

Before the determination of metals, the sample is dissolved by acid digestion (HNO3, H2O2 and HCl). Mineralisation takes place in closed microwave system. The sample undergoes neither crushing nor drying before mineralisation.

The reagents used for the mineralisation of chitosan are as follows: HNO3 (65 %) (Suprapur), HCl (37 %) (Suprapur), H2O2 (35 %). The 0.5 to 2 g sample of chitin-glucan is placed in a flask to which are added 25 ml of HNO3, 2 ml of HCl and 3 ml of H2O2. The whole is then submitted to microwave digestion (Power of 60 % for 1 min, 30 % for 10 min, 15 % for 3 min, and 40 % for 15 min). The solution is then diluted in a volumetric flask with bidistilled water to a final volume of 25.0 ml.

The metal contents can then be determined.

 

  1. Procedure

 

The dissolved samples are nebulised and the resulting aerosol is transported in a plasma torch induced by a high frequency electric field. The emission spectra are dispersed by a grating spectrometer and the line intensity is evaluated by a detector (photomultiplier).  The detector signals are processed and controlled by a computer system. A background noise correction is applied to compensate for the background noise variations.

 

  1. Expression of the results

The metal concentrations in the oenological products are expressed in mg/kg

Appendix III : Total bacteria count by counting the colonies obtained at 30 °C

 

PCA medium

Composition:

Peptone

5.0 g

Yeast extract

2.5 g

Glucose  

1.0 g

Agar-agar

15 g

Adjusted to

pH 7.0

Water

complete to 1000 ml

The medium is sterilised before use in an autoclave at 120 °C for 20 min.

The Petri dishes are inoculated by pour plate method and spiral plating method.

After inoculation, they are incubated at 30 °C in aerobiosis for 48 to 72 hours.

Count the CFU number.

Appendix IV : Enumeration of Enterobacteria is carried out according to the horizontal method by means of the colony count technique

 at 30 °C

 

VRBG medium

Composition:

Peptone

7 g

Yeast extract

3 g

Glucose

10 g

Sodium Chloride

5 g

Crystal Violet

0.002 g

Neutral Red

0.03 g

Agar-agar

13 g

Bile salts

1.5 g

Adjusted to

pH 7.4

Water

complete to 1000 ml

The medium is sterilised before use in an autoclave at 120 °C for 20 min.  

The Petri dishes are inoculated by pour plate method and spiral plating method.

After inoculation, they are incubated at 30 °C in aerobiosis for 18 to 24 hours.

Count the CFU number.

Appendix V : Enumeration of yeasts by counting

 

YGC medium

Composition:

Yeast extract

5.0 g

D-glucose

20 g

Agar-agar

14.9 g

Choramphenicol  

0.1 g

Adjusted to

pH 6.6

Water

complete to 1000 ml

The medium is sterilised before use in an autoclave at 120 °C for 20 min.

The Petri dishes are inoculated by pour plate method and spiral plating method.

After inoculation, they are incubated at 25 °C in aerobiosis for 3 to 5 days without being turned over.

Count the number of yeasts.

 

Appendix VI :Enumeration of the moulds by counting

YGC medium

Composition:

Yeast extract

5.0 g

D-glucose

20 g

Agar-agar

14.9 g

Choramphenicol

0.1 g

Adjusted to

pH 6.6

Water

complete to 1000 ml

The medium is sterilised before use in an autoclave at 120 °C for 20 min.

The Petri dishes are inoculated by pour plate method and spiral plating method.

After inoculation, they are incubated at 25 °C in aerobiosis for 3 to 5 days without being turned over.

Count the number of moulds.

Chitosan

COEI-1-CHITOS Chitosan

[]n

CAS number Chitosan : [9012-76-4]

Chitosan

  1. Purpose, origin and applicability

Chitosan, a natural polysaccharide prepared of fungal origin, is initially extracted and purified from reliable and abundant food or biotechnological fungal sources such as Agaricus bisporus or Aspergillus niger.

Chitosan is obtained by hydrolysis of a chitin-rich extract. Chitin is a polysaccharide composed of several N-acetyl-D-glucosamine units interconnected by β (1.4) type linkages.

Chitosan is composed of glucosamine sugar units (deacetylated units) and N-acetyl-D-glucosamine units (acetylated units) interconnected by β (1.4) type linkages.

It is used as a fining agent in the treatment of musts for flotation clarification to reduce cloudiness and the content of unstable colloids.

It is also used for stabilising wines. This polymer actually helps eliminate undesirable micro-organisms such as Brettanomyces.

  1. Synonyms

Poly(N-acetyl-D-glucosamine)-poly(D-glucose).

  1. Labelling

The following information must be stated on the packaging label: exclusively fungal origin, product for oenological use, use and conservation conditions and use-by date.

  1. Characters

4.1.    Aspect and solubility

Chitosan comes in the form of a white, odourless and flavourless powder. Chitin-glucan is almost completely insoluble in aqueous or organic medium.

4.2.    Purity and soluble residues

 

The purity of the product must be equal to or higher than 95 %.

Dissolve 5 g of chitin-glucan in 100 ml of bidistilled water and agitate for 2 minutes. Filter after cooling on a fine mesh filter or membrane.

Evaporate the filtrate and dry at 100-105 °C. The content of solubles should not be higher than 5 %.

  1. Tests

5.1.    Determination of the acetylation degree and chitosan origin

5.1.1.  Determination of the acetylation degree

The acetylation degree is determined by potentiometric titration, using the method described in Appendix I.

5.1.2.  Determination of the source

Chitosan, as a natural polymer, is extracted and purified from fungal sources; it is obtained by hydrolysis of a chitin-rich extract. This chitosan is considered identical to chitosan from shellfish in terms of structures and properties.

An identification of the origin of chitosan is made based on 3 characteristics: content of residual glucans (refer to method in annex II), viscosity of chitosan in solution 1 % and settled density (following settlement).

Only fungal origin chitosan has both contents of residual glucan > at 2 %, a settled density ≥ at 0,7 g/cm3 and viscosity in solution 1 % in acetic acid 1 % < at 15 cPs

 

5.2.    Loss during desiccation

In a glass cup, previously dried for 1 hour in an oven at 100-105 °C and cooled in a desiccator, place 10 g of the analyte. Allow to desiccate in

the drying oven at 100-105 °C to constant mass. Weigh the dry residue amount after cooling in the desiccator.

The weight loss must be lower than 10 %.

Note: all the limits stated below are reported in dry weight except for the microbiological analyses

 

5.3.    Ashes

Incinerate without exceeding 600 °C the residue left from the determination of the loss during desiccation as described in 5.2. Allow to calcine for 6 hours. Allow the crucible to cool in a desiccator and weigh.

The total ash content should not be higher than 3 %.

5.4.    Preparation of the test solution

Before determining the metals, the sample is dissolved by acid digestion (HNO3, H2O2 and HCl). Mineralisation is performed in a closed microwave system. The sample undergoes neither crushing nor drying before mineralisation.

The reagents used for the mineralisation of chitosan are as follows: HNO3 (65 %) (Suprapur), HCl (37 %) (Suprapur), H2O2 (35 %). The 0.5 to 2 g sample of chitosan is placed in a flask to which are added 25 ml of HNO3, 2 ml of HCl and 3 ml of H2O2. This is submitted to microwave digestion with a maximum power of 1200 watts; Power of 60 % for 1 min, 30 % for 10 min, 15 % for 3 min, and 40 % for 15 min). The solution is diluted in a volumetric flask with bidistilled water to a final volume of 25.0 ml.

The metal contents can then be determined.

 

5.5.    Lead

Lead is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The lead content must be lower than 1 mg/kg.

It is also possible to achieve lead determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

 

5.6.    Mercury

Mercury is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The mercury content must be lower than 0.1 mg/kg.

It is also possible to achieve mercury determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

 

5.7.    Arsenic

Arsenic is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The arsenic content must be lower than 1 mg/kg.

It is also possible to achieve arsenic determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

5.8.    Cadmium

Cadmium is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The cadmium content must be lower than 1 mg/kg.

It is also possible to achieve cadmium determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

5.9.    Chromium

Chromium is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The chromium content must be lower than 10 mg/kg.

It is also possible to achieve chromium determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

5.10. Zinc

Zinc is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The zinc content must be lower than 50 mg/kg.

It is also possible to achieve zinc determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

5.11. Iron

Iron is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The iron content must be lower than 100 mg/kg.

It is also possible to achieve iron determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

5.12. Copper

Copper is determined by atomic absorption spectrophotometry, using the method described in appendix II.

The copper content must be lower than 30 mg/kg.

 

It is also possible to achieve copper determination by atomic absorption, using the method described in chapter II of the International Oenological Codex.

 

5.13. Microbiological control

5.13.1.     Total bacteria count

The total bacteria count is performed according to the horizontal method by means of the colony count technique at 30 °C on the PCA medium described in appendix III.

Less than 1000 CFU/g of preparation.

It is also possible to carry out the enumeration as described in chapter II of the International Oenological Codex.

5.13.2.     Enterobacteria

The enumeration of Enterobacteria is carried out according to the horizontal method by means of the colony count technique at 30 °C described in appendix IV.

Less than 10 CFU/g of preparation.

5.13.3.     Salmonella

Carry out the enumeration as described in chapter II of the International Oenological Codex.

Absence checked on a 25 g sample.

5.13.4.     Coliform bacteria

Carry out the enumeration as described in chapter II of the International Oenological Codex.

Less than 100 CFU/g of preparation.

5.13.5.     Yeasts

The enumeration of yeasts is carried out according to the horizontal method by means of the colony count technique at 25 °C on the YGC medium described in appendix VI.

Less than 100 CFU/g of preparation.

It is also possible to carry out the enumeration as described in chapter II of the International Oenological Codex.

5.13.6.     Moulds

The enumeration of moulds is carried out according to the horizontal method by means of the colony count technique at 25 °C on the YGC medium described in appendix VII.

Less than 100 CFU/g of preparation.

It is also possible to carry out the enumeration as described in chapter II of the International Oenological Codex.

  1. Ochratoxin A testing

Prepare an aqueous solution (distilled water) of chitosan at 1 % and agitate for 1 hour, then carry out determination using the method described in the Compendium of International Methods of Analysis of Wine and Musts.

Less than 5 μg/kg.

6.1.    Storage

Keep container closed and store in a cool and dry place.

 

Appendix I: Determination of the acetylation degree

 

  1. Principle

 

This method consists in determining the acetylation degree of chitosan by titration of the amino groups. The acetylation degree is the ratio of the number of N-acetyl-glucosamine units to the number of total monomers.

This method is based on the method described by Rinaudo et al., (1999).

The titration of a chitosan solution by means of NaOH at 0.1 M must be performed in order to identify two pH jumps from 0 to 14.

Chitosan is dissolved in 0.1M HCl, the amino groups (on the deacetylated glucosamine units (G)) are positively charged (HCl in excess)).

The chitosan solution (of known quantity) is titrated by NaOH of known concentration.  In the first part of the reaction, the excess quantity of HCl is determined:

1.1.    HCl (excess)+NaOH+ NH3+Cl-  -->  NaCl + H2O + NH3+Cl-

After the first pH jump, the quantity of charged amino groups is determined:

1.2.    HCl +H2O + NH3+Cl-+ NaOH --> NH2 + 2H2O + 2NaCl

1.3.    After the second pH jump, the excess quantity of NaOH is measured.

The determination of the NaOH volume between the two jumps makes it possible to identify the quantity of charged amines.

  1. Reagents and materials

2.1.    Commercial preparation of chitosan

2.2.    Distilled or deionised water

2.3.    Chlorhydric acid 0,3 M

2.4.    Sodium Hydroxide 0,1M

2.5.    Glass cylindrical flasks, pipettes, burettes…

2.6.    Magnetic mixer and stir bar

2.7.    pH-meter with temperature sensor.

  1. Samples preparation

 

Before determination, the samples are prepared according to the protocol described hereafter:

100 mg of chitosan are placed into a cylindrical flask to which 3 ml of 0.3 M HCl and 40 ml of water are added. Agitate for 12 hours.

 

  1. Procedure

 

First introduce the pH electrode of the pH-meter as well as the temperature sensor into the cylindrical flask. Check that the pH value is lower than 3.

To bring to pH = 1, add a V1 volume (ml) of HCl 0.3 M and agitate.

Then to bring to pH = 7 with a V2 volume (ml) of 0.1 M NaOH 

These operations can be carried out using an automatic titrator.

  1. Expression of results

 

The acetylation degree of chitosan is expressed in %. This formula is the ratio of the mass of acetylated glucosamine (aG) units in g actually present in the sample, to the mass in g that would be present if all the groups were acetylated, where:

  • Mcs: dry weight of chitosan in g

For a 1 g sample

With G = Glucosamine part; a = acetylated part

aG weight actually present (in g) =

aG weight if all the deacetylated groups were acetylated (in g) =

The acetylation degree will be equal to DA, where:

Bibliography

  • Rinaudo, M., G. Pavlov and J. Desbrieres. 1999. Influenced of acetic acid concentration on the solubilization of chitosan. Polym. 40, 7029-7032.

 

Appendix II: Determination of the residual glucan content

 

  1. Principle

 

This method consists in determining the content of residual glucans in chitosan by means of spectrophotometry.

This method is based on a colorimetric reaction with a response depending on the degradation of the starch hydrolysates by hot concentrated sulphuric acid.

This degradation gives a brown yellow compound with a colour intensity proportional to the content of residual glucans.

  1. Reagents and materials

2.1.    Glucan 97% (Société Mégazyme)

2.2.    Commercial preparation of chitosan

2.3.    Distilled or deionised water

2.4.    Ethanol

2.5.    Acetic acid 1%

2.6.    Solution of phenol 5%

2.7.    Glacial acetic acid 100%

2.8.    Glass cylindrical flasks, pipettes, volumetric flasks,…

2.9.    Magnetic mixer and stir bar

2.10. Chronometer

 

  1. Preparation of the standard range

A stock solution of glucan (glucan with a purity of 97 % is provided by the company Megazyme) is prepared according to the precise protocol described hereafter:

500 mg of glucan are introduced into a volumetric flask of 100 ml into which 6 ml of ethanol and 80 ml of distilled water are added.

Agitate and boil out to allow glucan dissolution

Allow to cool, adjust to the filling mark with water

Agitate for 30 minutes.

Pour 1 ml of this solution into a 50 ml volumetric flask and adjust to the filling mark with 1 % acetic acid.

The solution is ready to use to produce the standard range according to the protocol hereafter.

Stock solution V (ml)

Water V (ml)

Glucan M (μg)

0

1

0

0.1

0.9

10

0.3

0.7

30

0.5

0.5

50

0.7

0.3

70

  1. Samples preparation

Before determination, the samples are prepared according to the protocol described hereafter:

100 mg of chitosan are placed into a 50 ml volumetric flask to which 25 ml of 1 % acetic acid are added.

Agitate for 12 hours then adjust to the filling mark.

  1. Procedure

In a test tube, add 1 ml of the analyte solution, 1 ml of phenol at 5 % and 5 ml of concentrated sulphuric acid.

Agitate this mixture using a vortex for 10 s, then allow to cool for 1 hour.

The absorbance A is measured at 490 nm.

  1. Expression of the results

Determine the glucan content in µg/g from the calibration curve (0-70 μg). This content is expressed in μg/g of chitosan.

Appendix III: Metal determination by atomic emission spectroscopy

 

  1. Principle

 

This method consists in measuring atomic emission by an optical spectroscopy technique.

 

  1. Sample preparation

Before the determination of metals, the sample is dissolved by acid digestion (HNO3, H2O2 and HCl). Mineralisation takes place in closed microwave system. The sample undergoes neither crushing nor drying before mineralisation.

The reagents used for the mineralisation of chitosan are as follows: HNO3 (65 %) (Suprapur), HCl (37 %) (Suprapur), H2O2 (35 %). The 0.5 to 2 g sample of chitosan is placed in a flask to which are added 25 ml of HNO3, 2 ml of HCl and 3 ml of H2O2. The whole is then submitted to microwave digestion (Power of 60 % for 1 min, 30 % for 10 min, 15 % for 3 min, and 40 % for 15 min). The solution is then diluted in a volumetric flask with bidistilled water to a final volume of 25.0 ml.

The metal contents can then be determined.

  1. Procedure

 

The dissolved samples are nebulised and the resulting aerosol is transported in a plasma torch induced by a high frequency electric field. The emission spectra are dispersed by a grating spectrometer and the line intensity is evaluated by a detector (photomultiplier).  The detector signals are processed and controlled by a computer system. A background noise correction is applied to compensate for the background noise variations.

 

  1. Expression of the results

The metal concentrations in chitosan are expressed in mg/kg.

 

Appendix IV: Total bacteria count by counting the colonies obtained at 30 °C

 

PCA medium

Composition:

Peptone

5.0 g

Yeast extract

2.5 g

Glucose  

1.0 g

Agar-agar

15 g

Adjusted to

pH 7.0

Water

complete to 1000 ml

The medium is sterilised before use in an autoclave at 120 °C for 20 min.

The Petri dishes are inoculated by pour plate method and spiral plating method.

After inoculation, they are incubated at 30 °C in aerobiosis for 48 to 72 hours.

Count the CFU number.

Appendix V: Enumeration of Enterobacteria is carried out according to the horizontal method by means of the colony count technique at 30 °C

 

VRBG medium

Composition:

Peptone

7 g

Yeast extract

3 g

Glucose

10 g

Sodium Chloride

5 g

Crystal Violet

0.002 g

Neutral Red

0.03 g

Agar-agar

13 g

Bile salts

1.5 g

Adjusted to

pH 7.4

Water

complete to 1000 ml

The medium is sterilised before use in an autoclave at 120 °C for 20 min.

The Petri dishes are inoculated by pour plate method and spiral plating method.

After inoculation, they are incubated at 30  °C in aerobiosis for 18 to 24 hours.

Count the CFU number.

Appendix VI : Enumeration of yeasts by counting

 

YGC medium

Composition:

Yeast extract

5.0 g

D-glucose

20 g

Agar-agar

14.9 g

Choramphenicol  

0.1 g

Adjusted to

pH 6.6

Water  

complete to 1000 ml

The medium is sterilised before use in an autoclave at 120 °C for 20 min.

The Petri dishes are inoculated by pour plate method and spiral plating method.

After inoculation, they are incubated at 25 °C in aerobiosis for 3 to 5 days without being turned over.

Count the number of yeasts.

 

Appendix VII : Enumeration of the moulds by counting

YGC medium

Composition:

Yeast extract

5.0 g

D-glucose

20 g

Agar-agar

14.9 g

Choramphenicol  

0.1 g

Adjusted to

pH 6.6

Water

complete to 1000 ml

The medium is sterilised before use in an autoclave at 120 °C for 20 min.

The Petri dishes are inoculated by pour plate method and spiral plating method.

After inoculation, they are incubated at 25 °C in aerobiosis for 3 to 5 days without being turned over.

Count the number of moulds.

Citric acid, monohydrate

COEI-1-CITACI Citric acid, monohydrate

Monohydrated 3-Carboxy-3-hydroxypentanedioic acid

Acidum citricum

SIN NO. 330

  1. Objective, Origin and Scope of Application

 

Citric acid can be used to chemically acidify wines or as a stabilizing agent to limit, in particular, the risks of iron breakdown, or again, for prewashing filter plates.  Its maximum proportions in wine may be subject to statutory limits.

  1. Labelling

The label should indicate product concentration, even when included in mixtures, as well as its safety and storage conditions.

  1. Properties

 

Citric acid is found in the form of colorless, translucent crystals which are rather friable and slightly efflorescent, or in crystalline powder form.

  1. Solubility

Water at 20 °C

very soluble

Alcohol, 95% by vol.

very soluble

Glycerol 

very soluble

Ethyl ether

31.5 g/l

Aqueous citric acid is inert in polarized light.

  1. Identifying Characteristics

5.1.     Verify total solubility in water.  A 1 pp 100 solution (m/v) shows an acid reaction to methyl orange (R).

5.2.     Place 2 ml of an aqueous 1 g/l citric acid solution and 0.5 ml of mercury (II) sulfate solution (R) in a test tube.  Bring to a boil and add several drops of 2 pp 100 potassium permanganate solution (R). A white precipitate should form.

5.3.     Add 1 drop of bromine water (R), 3 drops of concentrated sulfuric acid (R) and 1 drop of saturated potassium permanganate solution to 0.1 ml of 10 pp 100 (m/v) aqueous citric acid solution.Bring to a boil.

Add 2 ml of concentrated sulfuric acid (R).  Heat again until completely dissolved.  Let cool, then add 0.1 ml of beta-naphthol (R).  A green coloring should appear. A pink coloring is obtained under the same conditions if sulforesorcin reagent (R) is used under the same conditions.

5.4.     Place 5 ml of chloroform or dichloromethane in a test tube.  Add 100-200 mg of citric acid.  Shake.  The crystals or crystalline powder should collect together at the surface of the liquid.  Under these same conditions, tartaric acid collects at the very bottom of the tube.

  1. Tests

6.1.     Foreign Substances

Citric acid should be soluble without residue in its weight of water and in twice its weight of 95% alcohol (by volume).

6.2.     Sulfur Ash

After calcination at 600 °C 25 °C, the concentration of sulfur ash should not be greater than 0.5 g/kg.

6.3.     Tartaric Acid Determination

Add 2 drops of sulforesorcinic reagent (R) and 2 drops of 10 pp 100 (m/v) citric acid solution to 2 ml of concentrated sulfuric acid (R). Heat to 150 °C. The solution should not develop a violet coloring.

6.4.     Preparing the Solution for Tests

Prepare a 10 parts per 100 (m/v) solution.

6.5.     Chlorides

Add 14.5 ml of water, 5 ml of nitric acid diluted to 10 pp 100 (R) and 0.5 ml of 5 pp 100 silver nitrate solution (R) to 0.5 ml of the solution prepared for tests under paragraph 6.4.  After sitting for 15 minutes in the dark, there should be no clouding. If clouding does occur, it should be less intense than that observed in a control prepared as indicated in the Annex. (Chloride content expressed in terms of hydrochloric acid should be less than 1 g/kg).

6.6.     Sulfates

Add 18 ml of water, 1 ml of diluted hydrochloric acid (R) and 2 ml of 10 pp 100 barium chloride solution diluted to 10 pp 100 (R) to 1 ml of the solution prepared for tests under paragraph 6.4.  After 15 minutes, there should be no clouding.  If tclouding does occur, it should be less intense than that observed in a control prepared by replacing the test solution with 1 ml of 0.1 g/l sulfuric acid solution.  (Sulfate content expressed in terms of sulfuric acid should be less than 1 g/kg).

6.7.     Oxalic Acid and Barium

Neutralize 5 ml of the solution prepared for tests under paragraph 6.4 by adding concentrated ammonium hydroxide (R).  Add 2 drops of acetic acid (R) and 5 ml of saturated calcium sulfate solution (R).  There should be no clouding.(Oxalate content expressed in terms of oxalic acid should be less than 0.1g/kg).

6.8.     Iron

Add 1 ml of concentrated hydrochloric acid (R) and 2 ml of 5 pp 100 potassium thiocyanate solution (R) to 10 ml of the solution prepared for tests under paragraph 6.4.  The resulting red coloration should be less intense than that observed in a control using 1 ml of iron (III) salt solution in a concentration of 0.010 g of iron per liter, 9 ml of water and the same quantities of the same reagents.  (Iron content should be less than 10 mg/kg).

Iron may also be analytically quantified by atomic absorption spectometry in accordance with the technique detailed in the Compendium.

6.9.     Cadmium

Using the method described in the Annex, quantify cadmium analytically in the test solution prepared according to Par. 6.4.  (Cadmium content should be less than 1 mg/kg).

6.10. Lead

Using the method described in the Compendium, determine lead content analytically in the test solution prepared according to Par. 6.4.  (Lead content should be less than 1 mg/kg).

6.11. Mercury

Using the method described in the Annex, determine the mercury content analytically in the test solution prepared according to Par. 6.4. (Merucry content should be less than 1 mg/kg).

6.12. Arsenic

Using the method described in the Annex, determine the arsenic content analytically in the test solution prepared according to Par. 6.4. (Arsenic content should be less than 1 mg/kg).

  1. Storage

Citric acid should be stored in a dry place in air-tight bags.

Carboxymethylcellulose (cellulose gum, CMC)

COEI-1-CMC Carboxymethylcellulose (cellulose gum) (CMC)

INS no. 466

CAS [9004-32-4]

  • where R = H or CH2COONa
  1. Subject, origin and scope

Carboxymethylcellulose (cellulose gum) for oenological use is prepared exclusively from wood by treatment with alkali and monochloroacetic acid or its sodium salt.  Carboxymethylcellulose inhibits tartaric precipitation through a "protective colloid" effect. A limited dose is used.

  1. Synonyms

Cellulose gum, CMC, Sodium CMC, Sodium salt of a carboxymethyl ether of cellulose, NaCMC

 

  1. Labelling

Labelling must mention that the carboxymethylcellulose is for use in food, as well as safety and preservation conditions.

  1. Characteristics

 

4.1.     Description

Granular or fibrous powder, blank or slightly yellowish or greyish, slightly hygroscopic, odourless and tasteless. This may be proposed in

the form of a concentrate for solution in wine prior to use. Solutions must contain at least 3,5 % carboxymethylcellulose.

4.2.     Chemical formula

The polymers contain anhydroglucose units substituted with the following general formula: [C6H7O2(OH)x(OCH2COONa)y]n where

  • N is the degree of polymerisation
  • x = from 1.50 to 2.80
  • y = from 0.2 to 1.50
  • x + y = 3.0
  • (y = degree of substitution)

Note: Only the carboxymethylcellulose possessing a degree of substitution between 0.6 and 1.0 are completely soluble.

 

4.3.     Degree of substitution

Evaluate the degree of substitution using the method described below. The degree of substitution must lie between 0.60 and 0.95.

 

4.4.     Molecular weight

Ranges from 17,000 to 300,000 (degree of polymerisation from 80 to 1,500). The molecular weight can be evaluated through measurement of viscosity.

The viscosity of a 1 % solution must lie between 10 and 15 , or between 20 and 45 for a 2 % solution, or between 200 and 500 for a 4 % solution.

4.5.     Composition

Measure the carboxymethylcellulose composition using the method described below. The carboxymethylcellulose content must be at least 99.5 % of the anhydrous substance.

 

  1. Tests

5.1.     Solubility

Forms viscous colloidal solution with water.  Insoluble in ethanol.

 

5.2.     Foam test

Vigorously shake a 0.1 % solution of the sample.  No layer of foam appears (this test distinguishes sodium carboxymethylcellulose from other cellulose ethers and from alginates and natural gums).

 

5.3.     Precipitate Formation

To 5 mL of an 0.5% solution of the sample add 5 mL of a 5 % solution of copper sulfate or of aluminium sulfate. No precipitate appears. (This test permists the distinction of sodium carboxymethyl cellulose ethers from other cellulose ethers, and from gelatine, carob bean gum and tragacanth gum)

 

5.4.     Colour reaction

Add 0.5 g of powdered carboxymethylcellulose sodium to 50 mL of water, while stirring to produce a uniform dispersion. Continue the stirring until a clear solution is produced. To 1 mL of the solution, diluted with an equal volume of water, in a small test tube, add 5 drops of 1­naphthol. Incline the test tube, and carefully introduce down the side of the tube 2 mL of sulfuric acid so that it forms a lower layer. A red-purple colour develops at the interface.

 

5.5.     Moisture - Loss on drying

Measure the loss on drying using the method described below. Not more than 12 % after drying.

5.6.     pH of a 1 % solution

No less than 6 and no more than 8.5 pH units.

5.7.     Arsenic

Quantifythe arsenic using the method described in chapter II.  The arsenic content must be lower than 3 mg/kg

5.8.     Lead

Quantify the lead using the method described in chapter II. The lead content must be lower than 2 mg/kg

5.9.     Mercury

Quantify the mercury using the method described in chapter II.  The mercury content must be lower than 1 mg/kg

5.10. Cadmium

Quantify the cadmium using the method described in chapter II.  The cadmium content must be lower than 1 mg/kg

 

5.11. Free Glycolate

Quantify the glycolate using the method described below. The carboxymethylcellulose should not contain more than 0.4 % (calculated in sodium glycolate percentage of the anhydrous substance).

5.12. Sodium

Quantify the sodium using the method described in chapter II. The sodium content must be lower than 12.4 % of the anhydrous substance

5.13. Sodium chloride

Quantify the sodium chloride using the method described below.   The carboxymethylcellulose must not contain more than 0.5 % of the anhydrous substance.

Annexes

  1. Loss on drying

1.1.     Objective

This test determines the volatile part of carboxymethylcellulose. The result of this test is used to calculate the total solids of the sample and by extension, all the volatile substances at the test temperature are regarded as moisture.

1.2.     Interest and use The measurement of water content (by taking account of the purity) is used to measure the quantity of carboxymethylcellulose in commercial products.

1.3.     Equipment

1.3.1.  Drying oven at 105 °C 3 °C;

1.3.2.  Weighing bottle 50 mm in internal diameter and 30 mm in height or equivalent;

1.3.3.  Precision balance

1.4.     Test

1.4.1.  Weigh between 3 and 5 g of sample to ± 1 mg, in a weighing bottle which has already been tared.

1.4.2.  Place the weighing bottle without its lid in the drying oven for four hours. Let cool in a desiccator, replace the lid and weigh.

1.4.3.  Continue the process until constant weight

1.5.     Calculation

1.5.1.  Calculate the percentage of the water content M according to the formula:

Where

  • A = loss of weight by drying (in g);
  • B = initial mass of sample.

 

  1. Sodium Glycolate

2.1.     Objective

This test covers the determination of sodium glycolate contained in the purified carboxymethylcellose containing not more than 2 % sodium glycolate.

2.2.     Summary of the test method

Carboxymethyl cellulose dissolved in acetic acid (50 %), precipitated with acetone in the presence of sodium chloride and the insoluble is eliminated by filtration. The filtrate containing the glycolate sodium (in the form of glycolic acid) is treated to remove the acetone and reacts with 2,7-dihydroxynaphthalene. The resulting colour is measured at 540 nm with a calibrated spectrophotometer using solutions of known concentrations.

2.3.     Interest and use

This test method (along with moisture and sodium chloride) is must been used when measuring the quantity of polymer in the substance. It must be used to check the purity of carboxymethylcellulose required by public health regulations.

2.4.     Equipment

2.4.1.  Spectrophotometer capable of carrying out analysis at 540 nm;

2.4.2.  Spectrophotometer cells, 1 cm of optical path

2.4.3.  Aluminium paper in squares approximately 50 × 50 mm;

2.4.4.  Precision balance

2.5.     Reagents

2.5.1.  Acetic acid, glacial (purity ≥ 99 %);

2.5.2.  Acetone (purity ≥ 99 %);

2.5.3.  2,7-dihydroxynaphtalene solution (0.100 g/L): Dissolve 100 mg 1 mg of 2,7­dihydroxynaphthalene (naphthalenediol) in 1 L of sulphuric acid. Before using, allow the solution to stand until the initial yellow colo disappears. If the solution is dark, eliminate it and prepare a new one with a different supply of sulphuric acid. This solution remains stable for one month when stored in a dark bottle;

2.5.4.  Standard glycolic acid solution at 1 mg/mL: dry several grams of glycolic acid in a desiccator for at least sixteen hours at room temperature. Weigh 100 mg ± 1 mg, pour into a 100 mL graduated flask, dissolve with water, adjust with water to the filling mark. Do not keep solution longer than 30 days;

2.5.5.  Sodium chloride (NaCl, purity ≥ 99 %);

Sulphuric acid concentrate (H2SO4 purity ≥ 98 %, ρ≥ 1.84).

2.6.     Preparation of the calibration curve

2.6.1.  In a series of five graduated 100 mL volumetric flasks, pour 0, 1, 2, 3 and 4 mL of the glycolic acid reference solution (to 1 mg / mL). Into each flask, add 5 mL of water, then 5 mL of glacial acetic acid, make up with acetone to the filling mark and mix. These flasks contain respectively, 0, 1, 2, 3 and 4 mg of glycolic acid.

2.6.2.  Pipet 2 mL of each of these solutions and transfer them into five 25 mL graduated flasks. Evaporate the acetone by heating the open graduated flasks, laid out vertically, in a water bath for exactly 20 min. Remove from the water bath and let cool at room temperature.

2.6.3.  Add 5 mL of 0.100 g/L 2,7-dihydroxynaphtalene solution, mix thoroughly, then add an additional 15 mL of 2,7-dihydroxynaphtalene solution and mix. Cover the mouth of the flasks with a small piece of aluminium foil, place the flasks upright in the water bath for 20 min. Remove from the water bath, let cool at room temperature and add sulphuric acid to the filling mark.

2.6.4.  Measure the absorbance of each sample at 540 nm against the blank using 1 cm optical depth cells. Plot the absorbance curve according to the corresponding quantity of glycolic acid (in mg) in each flask.

2.7.     Test method

2.7.1.  Weigh 0.500 g ± 0.001 g of sample and transfer into a 100 mL beaker. Moisten the sample entirely with 5 mL of acetic acid, followed by 5 mL of water, stir with a glass rod until dissolution is complete (usually requires approximately 15 minutes). Slowly add 50 mL of acetone while stirring, then approximately 1 g of sodium sulphate. Continue to stir for several minutes to ensure complete completely precipitation the carboxymethylcellulose.

2.7.2.  Filter using a paper filter previously soaked with small amount of acetone, and collect the filtrate in a 100 mL graduated flask. Use 30 mL of acetone to facilitate transfer of solid matter and to wash the filter cake. Make up to the filling mark with acetone and mix.

2.7.3.  In another 100 mL graduated flask, prepare a blank with 5 mL of water, 5 mL of glacial acetic acid, then make up to the filling mark with acetone and mix.

2.7.4.  Pipet 2 mL of the sample solution and 2 mL of the blank solution and pour them into two 25 mL graduated flasks. Evaporate the acetone as before (2.6.2).

2.7.5.  Measure the absorbance of the sample and infer the quantity of glycolic acid (in mg) using the calibration curve (2.6.4).

2.8.     Calculation: Calculate the content C (in %) of sodium glycolate (free glycolate) contained using the formula:

Where

  • B = glycolic acid (in mg) inferred using the calibration curve;
  • W = quantity of weighed carboxymethylcellulose (in g);
  • M = water content of the sample (in %);
  • 0.129 = (ratio of the molecular weight of sodium glycolate compared to the molecular weight of the glycolic acid)/10.

Note: if the test is carried out with pre-dehydrated carboxymethylcellulose, the formula becomes:

  • W = quantity of carboxymethylcellulose (dry) weighed (in g).
  1. Sodium chloride

3.1.     Objective This test method determines the sodium chloride content of the purified carboxymethylcellulose (> 98 %).

3.2.     Summary of the test method The sodium carboxymethylcellulose is dissolved in water and titrated by potentiometry with a silver nitrate solution. Hydrogen peroxide is added to reduce the viscosity of the solution.

3.3.     Importance and use This test method (along with moisture and sodium glycolate content) is used to calculate the degree of substitution of carboxymethylcellulose. It must be used to analyse highly purified grades of sodium carboxymethylcellulose (> 98 %).

3.4.     Equipment

3.4.1.  pH-meter capable of reading voltage (in mV), equipped with a silver electrode and a mercury sulphate reference electrode saturated with potassium sulphate.

3.4.2.  buret, 10 mL

3.4.3.  Precision balance.

3.4.4.  250 mL Erlenmeyer flask.

3.5.     Reagents

3.5.1.  Concentrated hydrogen peroxide (30 % in mV) (H2O2).

3.5.2.  Concentrated nitric acid (HNO3) (ρ 1.42).

3.5.3.  Silver nitrate, standard solution (0.1 N) - Dissolve 17.0 g of silver nitrate (AgNO3) in 1 L of water. Store in an amber glass bottle. Standardise the solution as follows: Dry the sodium chloride (NaCl) for 2 hrs at 120 °C. Weigh 0.65 g 0.0001 g in a 250 mL beaker and add 100 mL of water. Place on a magnetic stirrer, add 10 mL of HNO3, and immerse the electrodes of the pH-meter. Using a buret, add by 0.25 mL fractions the theoretical quantity of the AgNO3 solution. After each addition, wait approximately 30 seconds before carrying out readings of the corresponding voltages. When approaching the endpoint, decrease the additions to 0.05 mL. Record the voltage (in millivolts) according to the volume (in mL) of the titration solution, continue titration a few mL beyond the endpoint. Trace the potential values obtained in relation to the corresponding volumes of titrated solution, and determine the potential of the equivalence point according to the singular point of the curve obtained.

Calculate the normality, N, as follows:

 

where

  • A = NaCl used in g,
  • B = added AgNO3 solution in mL,
  • 58.45 = molecular mass of the NaCl in g, 
  • 3.5.4 Sodium chloride (NaCl, purity ≥ 99%).

3.6.     Test method

3.6.1.  Weigh 5 g 0.0001 g of sample in a 250 mL beaker. Add 50 mL of water and 5 mL of H2O2 (30 %). Place the beaker on a steam bath, stirring occasionally until the solution is fluid. If dissolution does not occur within 20 min, add 5 mL of H2O2 and heat until dissolution is complete.

3.6.2.  Cool the beaker, add 100 mL of water and 10 mL of HNO3. Place it on the magnetic stirrer and titrate with the 0.1 N AgNO3 solution (3.5.3) up to the equivalence point.

3.7.     Calculation

3.7.1.  Calculate the sodium chloride content C (in %) as follows:

 

Where:

  • A = volume of AgNO3 solution added (in mL);
  • N = Normality of the AgNO3 solution;
  • G = weight of the sample used (in g),
  • B = Moisture, given extemporaneously (in %) as per paragraph 1 and 584.5 = molecular mass of NaCl ×10 (in g).
  1. Degree of substitution

4.1.     Objective This method is used to determine the degree of etherification (of substitution) of the carboxymethylcellulose used.

4.2.     Summary of the test method Pre-purified carboxymethylcellulose mineralises in the presence of sulphuric acid. The weight of the residual sodium sulphate enables inference of the sodium content and by extension the degree of substitution.

4.3.     Importance and use This test method is used to determine the number of substituent groups added to the basic cellulose backbone.

4.4.     Equipment

4.4.1.  500 mL Erlenmeyer flask.

4.4.2.  Precision balance.

4.4.3.  Sintered glass filter.

4.4.4.  Filter-flask.

4.4.5.  Porcelain crucible.

4.4.6.  Drying oven at 110 °C.

4.4.7.  Desiccator.

4.4.8.  Bunsen burner or muffle furnace at 600 °C.

4.5.     Reagents

4.5.1.  Methanol or ethanol (purity ≥ 98 %)

4.5.2.  0.1 N silver nitrate (AgNO3)

4.5.3.  Acetone (purity ≥ 99 %)

4.5.4.  Sulphuric acid (purity ≥ 96 %)

4.5.5.  Ammonium carbonate (NH4HCO3)

4.6.     Preparation of the sample (This step is not necessary if the sample is assumed to contain at least 99.5 % of  of carboxymethylcellulose)Weigh 5 g of the sample 0.1 mg, and transfer into a 500 mL conical flask. Add 350 mL of methanol or ethanol (80 % volume). Stir the suspension for 30 min. Decant trough a tared glass filtering crucible under gentle suction. At the end of filtration, avoid drawing in air through the crucible. Repeat the treatment until the 0.1 N silver nitrate test for the chloride ions is negative for the crucible. Normally, three washings suffisant. Transfer the carboxymethylcellulose into the same crucible. Eliminate the traces of alcohol by rinsing with acetone. Let the acetone evaporate into the air (under a hood) then in a drying oven at 110 °C until constant weight. Weigh for the first time after two hours. Cool the crucible each time in a desiccator and during the weighing, pay attention to the fact that sodium carboxymethyl cellulose is slightly hygroscopic.

4.7.     Test method In a porcelain crucible tared beforehand, weigh 2 g 0.1 mg of dried substance following the preparation above. Char with the Bunsen burner, first carefully with a small flame and then for 10 min with a large flame. Cool, then pour 3 to 5 mL of concentrated sulphuric acid onto the residue. Heat carefully with the fuming is finished. After cooling, add about 1 g of ammonium carbonate by pouring the powder onto the entire contents of the crucible. Reheat, initially with a small flame until no more smoke is released then at deep red for 10 min.

Repeat the sulphuric acid and ammonium carbonate washing if the residual sodium sulphate still contains carbon. Let the crucible cool in a desiccator and weigh. In place of adding the ammonium carbonate and heating by flame, the crucible can be placed in an over for one hour at approximately 600 °C.

4.8.     Calculate the sodium content of the sample extracted from alcohol by the formula

  • a = weight of residual sodium sulphateb = weight of the sample extracted from dry alcohol

4.9.     Calculate the degree of substitution using the formula:

 

  1. Composition in carboxymethyl cellulose 

Calculate the percentage of sodium carboxymethyl cellulose in the sample by deducting 100 % of the sum of percentages of sodium and sodium glycolate (free glycolate), determined separately by the procedures above.

Carboxymethyl cellulose content (in %) = 100 – (% NaCl + % sodium glycolate)

 

  1. Measurement of viscosity

6.1.     Objective

6.1.1.  This test method determines the viscosity of aqueous carboxymethylcellulose solutions within ranging from 10 to 10 000 mPa/s  at 25 °C.

6.1.2.  The concentration to be used for the test must be such that determination of the solution viscosity will be possible within the limits of the test.

6.1.3.  The results of the carboxymethylcellulose viscosity measurement by the present test method are not necessarily identical to the results obtained with other types of instruments used for the measurement of viscosity.

6.1.4.  The determinations are calculated on a dry weight, which requires knowledge of the water content of carboxymethylcellulose (see §1).

6.1.5.  The recommended Brookfield spindles and the speeds are shown in table 1, but they can be adapted for greater convenience.

Table 1: Spindles and speeds required by the viscometer

 Viscosity Range
(in mPa/s)

mobile n°

Speed
(in tr/min)

Scale

Factor

10 to 100

1

60

100

1

100 to 200

1

30

100

2

200 to 1000

2

30

100

10

1000 to 4000

3

30

100

40

6.2.     Interest and use This test method is used to estimate the molecular weight of carboxymethylcellulose

6.3.     Equipment

6.3.1.  Brookfield viscometer.

6.3.2.  Glass container, approximately 64 mm (2 ½ inches) in diameter and 152 mm (6 inches) tall, straight edged, 40 g capacity (12 oz).

6.3.3.  Precision balance

6.3.4.  Mechanical stirrers with a stainless steel blade fastened to a variable speed motor capable of functioning at 900 100 r/min under different load conditions.

6.3.5.  Water bath, at 25 °C 0.5 °C.

6.3.6.  Precision thermometer capable of reading temperatures ranging from 20 to 30 °C 0.1 °C.

6.4.     Test method

6.4.1.  Determine the water content following § 1.

6.4.2.  Calculate the dry weight of the sample in grams, M, required to prepare 240 g of the test solution as follows:

where:

  • A = desired dry mass of the sample in g, and
  • B = the water content of the sample in %.
    1.   Calculate the quantity of distilled water as follows:

where:

  • V = volume of distilled water in mL and 
  • S = mass of the sample in g.

6.4.4.  Add the quantity of water calculated in the jar. Position of the stirrer must allow a minimal clearance between the stirrer and the bottom of the container.

6.4.5.  Begin stirring and to slowly add the carboxymethylcellulose. Adjust stirring speed to approximately 900 ± 100 r/min and mix for 2 hrs. Do not allow the stirring speed exceed 1,200 r/min as higher speeds tend to affect the viscosity of certain carboxymethylcellulose solutions.

Note: If the sample is added too quickly, an agglomeration will occur, which could prevent the complete dissolution of the sample in the indicated time interval. 

6.4.6.  Remove the stirrer and transfer the container containing the sample to the water bath until a constant temperature is reached (approximately one hour). Check the temperature of the sample with a thermometer at the end of one hour and make sure that the test temperature has been reached.

6.4.7.  Remove the container containing the sample from the water bath and stir vigorously for 10 sec. Measure viscosity with the Brookfield viscometer, choosing the spindle and speed following table 1. Let the spindle turn for three minutes before carrying out the reading.

6.5.     Calculation

6.5.1.  Calculate viscosity, V, in millipascals per second (mP/s) as follows:

6.6.     Expression of results Express the result of Brookfield viscosity at 25 °C by indicating the concentration of the solution, the spindle, and the spindle speed used.

Fish glue

COEI-1-COLPOI Fish glue (Isinglass)

  1. Objective, Origin and Scope of Application

 

Fish glue is made from the swim bladder, gills and ears of certain fish, notably sturgeon.

It is produced in the form of colorless or slightly yellowish transparent sheets or, most frequently, in ribbons which have the appearance of dry parchment, or in vermiculated or powder form.

Fish glue expands in cold water and becomes opaque. It dissolves in hot water acidified with tartaric acid, leaving at most 3 pp 100 of residue composed of membranes. With 30-50 parts of hot water and after cooling, it forms a colorless, translucent jelly.

After partial hydrolysis, fish glue is often found in ready-to-use colloidal solution form stabilized by SO2.  In this case, it should be stored cool in a closed container.

Fish glue is used to clarify white and rose wines.

  1. Labelling

The label should indicate product concentration, even when used in mixtures, as well as its safety and storage conditions.  The expiration date and the SO2 content should be indicated on the label.

  1. Tests

3.1.    A hot water solution should be odorless and have no disagreeable taste.  Reaction should be neutral or slightly alkaline.  It precipitates with tannin.

Fish glue pH ranges between 3.5 and 4 when tartaric acid has been used to facilitate dissolution.

3.2.    Fish glue processed with a potassium hydroxide solution (R) should remain transparent and, after several hours, yield a colorless liquid which will produce a light, frothy precipitate over time.  Under the same conditions, the gelatin becomes opaque and difficult to make soluble.  It produces an abundant, white precipitate.

3.3.    Test for albuminoid substances.  Aqueous solutions should not form a precipitate when iron (III) sulfate solution (R) is added.

3.4.    Desiccation Loss

3.4.1.  Fish Glue in Solid Form

In a silica dish with cover and measuring 70 mm in diameter, place 2g fish glue. Oven dry at 100-105o for six hours. Allow to cool in the uncovered dish in a desiccator. Weigh. Let p be the quantity of dry residue. Weight loss should not exceed 18 pp 100.

3.4.2.  Fish Glue in a Liquid State

In a silica dish 70 mm in diamater place approximately 10 g fish glue colloidal solution, weight this amount with precision in the uncovered dish, dry in a water bath at 100o C for 4 hours and complete the drying process in the oven at 100-105o C for 3 hours. Allow to cool in the uncovered dish in the drying apparatus. Weigh the dry residue produced. Let p be the quantity added to 100 g colloidal solution. The dry residue should reach a minimum level of 1 pp 100.

All of the limiting values set forth above are stipulated for the dry product.

3.5.    Ash

Burn the dry residue in test 3.4 by gradually heating to 600o in a muffle furnace after dusting the fish glue with 0.1 to 0.3 g paraffin without ash, in order to prevent the mass of material from overflowing. Ash content should be less than 2 pp 100.

3.6.    Preparation of Test Solution

After eighing, dissolve the ash in 2 ml conventrated hydrochloric acid (R) and 10 ml water. Heat to stimulate dissolution and add distilled water until a volume equal to 25 times the weight of the dry fish glue is obtained. 1 ml of this solution contains the mineral substances derived from 0.04 g dry fish glue.

3.7.    Total Nitrogen

Refer to the technique described in the Annex.

Total nitrogen content should be greater than 14 pp 100.

3.8.    Iron

1 ml concentrated hydrochloric acid (R), one drop potassium permangante in concentration of 1 pp 100 (R) and 2 ml potassium thiocyanate in a concentration of 5 pp 100 (R) are added to 10 ml of the test solution prepared according to Par. 3.6).

If a red coloring appears, it must be less intense that that of a control prepared from 4.2 ml of iron (III) solution in a concentration of 0.010 g per liter, 5.8 ml water, and the same quantities of concentrated hydrochloric acid (R) and of potassium thiocyanate in a concentration of 5 pp 100.

Iron content should be less than 100 mg/kg.

The quantitative analysis of iron can also be implemented by atomic absorption spectometry, using the technique reported in the Compendium.

3.9.    Arsenic

Using the method described in the Annex, determine the arsenic content in the test solution prepared according to Par. 3.6. Arseniccontent should be less than 3 mg/kg..

3.10. Lead

Using the method described in the Compendium, determine the lead content in the test solution prepared according to Par. 3.6.  (Lead content should be less than 5 mg/kg).

3.11. Mercury

Using the method described in the annex, quantify the mercury content  in the test solution prepared according to Par. 3.6. (Mercury content should be less than 1 mg/kg).

  1. Storage

Fish glue should be stored in hermetic flasks. An expiration date should be specified.

Store colloidal solutions at temperatures of less than 10 °C to avoid rapid hydrolysis of the product during storage.

Copper sulfate, pentahydrate

COEI-1-CUISUL Copper sulfate, pentahhydrate

Copper (II) Sulfate, Pentahydrate

= 249.68

  1. Objective, Origin and Scope of Application

Copper sulfate is used in processing wines possessing so-called reduction "tastes" due to the presence of hydrogen sulfide or volatile thiols.

The copper sulfides thus formed precipitate and should be removed from wine.

This product must be used in compliance with copper sulfate pentahydrate limiting quantities; furthermore, there are statutory limits restricting the copper content in wines.

  1. Labelling

The label should indicate product concentration, even when used in mixtures, as well as its safety and storage conditions.

  1. Properties

Blue crystals which are minimally efflorescent in dry air.

  1. Composition

Minimum of 99 pp 100 CuSO4, 5H2O.

  1. Identifying Characteristics

Melting point: 110 °C with water loss.

An aqueous solution with ammonium hydroxide (R) produces a dark blue copper tetramine compound. A solution acidified with hydrochloric acid and a barium chloride solution (R) produces a white barium sulfate precipitate.

  1. Solubility

Water at 20 °C

286 g/l

Methanol

15.6 g/l

Insoluble in ethanol (95% alcohol by volume).

  1. Tests

7.1.    Preparing the Solution for Tests

Dissolve 10 g of the substance in water and fill to 50 ml.

7.2.    Appearance of the Test Solution

The test solution must be clear.

7.3.    Iron

Place 2 ml of the solution prepared for tests under paragraph 7.1 in a decanting glass and add 8 ml of water, 10 ml of 6M hydrochloric acid (R) and 10 ml of 4-methylpentane-2-one. Shake vigorously for 3 minutes.  After letting the mixture settle, decant the organic phase in a second decanting glass.  Add 10 ml of water then shake vigorously again for 3 minutes.  Separate out the aqueous phase and perform the test in the following manner:

Add 2 ml of citric acid solution (20 g of citric acid/100 ml), 0.10 ml of concentrated thioglycolic acid (HS-CH2-COOH) and a small amount of 6M ammonium hydroxide (10-10.4 g NH3/100 ml) to the aqueous phase until an alkaline reaction is triggered.  Dilute with water until a total volume of 20 ml is reached.  After 5 minutes, the sample should not be more intensely colored than the test carried out using the comparison solution described below.

7.3.1.  Preparation of the Comparison Solution

Iron (III) and ammonium sulfate solution 1

Dissolve 0.702 g of ammonium sulfate and iron (III) in 1.20 ml of 6M hydrochloric acid and fill to 100 ml with water.

Iron (III) and ammonium sulfate solution 2

Take 7 ml of ammonium sulfate and iron (III) (Par. 7.3.1.1) and fill to 100 ml with water.

1 ml of solution 2 corresponds to 10 µg of Fe(III).

7.3.2.  Test Using the Comparison solution

The comparison solution should be prepared prior to use in the following manner:

Take 1 ml of ammonium sulfate and iron (III) solution (2) and process in the same way as for the substance test.

N.B.: Iron content can also be analyzed by atomic absorption spectometry, using the method described in the Compendium.

The iron content limit is 100 mg/kg.

7.4.    Nickel

Add 2 ml of concentrated hydrochloric acid (R) and 1 ml of concentrated nitric acid (R) to the aqueous phase from paragraph 7.3.

After evaporating the solution, dissolve the residue in 1 ml of 6M nitric acid (R) and 19 ml of water. Dilute 1 ml of this solution to a total volume of 10 ml. To 2.50 ml of this dilute solution, add 6 ml of water (R), 5 ml bromine solution (R), 7 ml of 6M ammonium hydroxide solution and 3 ml of  dimethylgloxime solution in a concentration of 100 g in 100 ml of 96% ethanol by volume.  The solution should not exhibit any change after one minute when compared to a "blank" sample.

Nickel content can also be determined using the atomic absorption photometry method described in the Annex.

7.5.    Chlorides

Dilute 25 ml of the solution prepared for tests under paragraph 7.1 with 10 ml of water. After adding 8 ml of 6M sodium hydroxide, bring to a boil and heat the mixture in a 100 °C water bath until the precipitate has been completely deposited.  After cooling, dilute with water to obtain a total volume of 50 ml. Add 6 ml of water to 4 ml of filtrate and conduct the following test: add 1 ml of 6M nitric acid (R) and 1 ml 0f 0.1M silver nitrate (R).  Shake the sample after 5 minutes. There should be no more clouding than that seen in the control test conducted with the comparison solution.

(Limiting value: 100 mg/kg.)

7.5.1.  Preparation of the Comparison Solution

Dilute 4 ml of 0.1M sodium chloride solution (23.4 ml/100 ml) with water to yield a total volume of 100 ml. 1 ml corresponds to 142 µg Cl-.  Prepare the solution just before use.

 

7.5.2.  Control Test with the Comparison Solution

Take 1 ml of the sodium chloride solution (Par. 7.5.1) and proceed in the same manner as for the test on the substance.

7.6.    Lead

Using the technique explained in the Compendium, determine the lead content in the test solution (Par. 7.1). (Lead content should be less than 5 mg/kg).

7.7.    Mercury

Using the technique explained in the annex, determine the mercury content in the test solution (Par. 7.1). Mercury content should be less than 1 mg/kg.

7.8.    Arsenic

Using the technique explained in the annex, determine the arsenic content in the test solution (Par. 7.1). (Arsenic content should be less than 3 mg/kg).

7.9.    Quantitative Analysis

Weigh exactly 0.50 g of the substance and dissolve in 20 ml of water.  Add 5 ml 6M acetic acid and 2 g potassium iodide.  Titrate with a 0.1M sodium thiosulfate solution in the presence of starch (R).

1 ml of a 0.1M sodium thiosulfate solution which corresponds to 6.354 mg of Cu (II), or, if the result is expressed in terms of substance, to 24.97 mg of CuSO4,5H2O.

  1. Storage

Copper sulfate should be stored in a dry place in hermetically sealed containers.

Copper citrate

COEI-1-CUICIT Copper citrate x 2.5-hydrate

Copper citrate hemipentahydrate

x 2.5

CAS-number: 10402-15-0

molecular weight: 360 g/mol

  1. Subject, origin and field of application

Copper citrate is applied for the treatment of wine to remove fermentation and storage related off-flavours (sulphide off-flavours, flavours caused by reduction reactions, flavours caused by the presence of hydrosulfuric acid and mercaptans).

The copper sulphide formed during the treatment precipitates in wine as it is a very poorly soluble compound and can be separated by filtration.

Addition to the wine can be made directly or preferably by means of bentonite as a carrier material. The purity requirements of Codex resolution OENO 11/2003 apply for the bentonite used.

The addition to the wine is limited (resolution OENO 1/2008), legally permitted limits of copper contents in wine must be respected.

  1. Labelling

 

The product concentration, the batch number, the date of expiry, safety warnings and storage conditions have to be indicated on the label.

  1. Appearance

 

Light green to light blue granulated crystals.

  1. Content (Assay)

Minimum of 98 % copper citrate x 2.5-hydrate.

With products on carrier material, a minimum of 2 % copper citrate x 2.5-hydrate.

  1. Identification

Copper citrate dissolved in 10 % nitric acid reacts with ammonium hydroxide (R) to form a dark blue complex of tetramine copper.

Heating to dryness at more than 180 °C leads to the carbonization of the citrate.

  1. Solubility
  • Less than 0.05 g/L in water at 20 °C, in methanol and in ethanol.
  • Approx. 250 g/L in 10 % HCl (R).
  • Approx. 140-150 g/L in 10 % HNO3 (R).
  1. Tests
    1.     Preparation of the test solution

Dissolution of 10 g copper citrate in 100 mL 10 % HNO3 (R).

7.2.    Appearance of the test solution

The solution is light blue.

7.3.    Iron

Determination by atomic absorption spectrophotometry (AAS); content below 200 mg/kg.

Remark:

The method described in the OIV resolution (OENO 25/2000) leads to a dissolving-out of the iron in the test solution by shaking with 4-methylpentan-2-one and transfer into the organic phase. The iron concentration in the organic phase is not determined. The analysis is merely to test whether the second aqueous phase still contains iron.

By means of AAS, the iron content can be measured directly and precisely.

With a maximum of 200 mg iron per kilogramme of copper citrate and a treatment with at the most 1 g copper citrate per 100 litres of wine, the increase of the iron concentration in wine amounts to a maximum of 0.002 mg per litre and is thus negligible.

7.4.    Nickel

Determination by atomic absorption spectrophotometry (AAS); content below 5 mg/kg.

7.5.    Chloride

Add 1 mL silver nitrate solution 0.1 M to 4 mL of the test solution. After 5 minutes mix the sample.

The turbidity must not exceed that of the test conducted with the reference solution.

Reference solution:

Dilute 4 mL sodium chloride solution 0.1 M with water to a volume of 100 mL.

Blank test:

1 mL of the freshly prepared reference solution is used instead of the test solution. Proceed in the same way as in the test mentioned above.

Remark:

A pretreatment of the test solution is not necessary, since it is nitric acid.

7.6.    Lead

Determination by atomic absorption spectrophotometry (AAS); content below 5 mg/kg.

7.7.    Mercury

Determination by atomic absorption spectrophotometry (AAS); content below 1 mg/kg.

7.8.    Arsenic

Determination by atomic absorption spectrophotometry (AAS); content below 3 mg/kg.

7.9.    Assay

Pour 1 mL test solution, 20 mL water, 2 mL acetic acid 6 M, 2 g potassium iodide and 2 mL starch solution (R) into a titration vessel. Titration is conducted with 0.1 M sodium thiosulphate solution up to the colour change.

A consumption of 1 mL sodium thiosulphate solution corresponds to 6.354 mg Cu(II) or to 18 mg expressed as copper citrate.

  1. Storage

Copper citrate must be stored dry, protected from odours in hermetically closed packaging.

Diatomite

COEI-1-DIATOM Diatomite

Keiselguhr

Terre silicea

  1. Object, origin and field application

Diatomite is a sedimentary rock made up of siliceous shells (tests) of diatomite fossils (unicellular microscopic algae). For enological purposes, this rock is crushed, dried, shredded, purified through cleaning, and calcinated at a high temperature of 950 to 1000°C. Melted alkaly can be added during the calcination process.

It is used when pulverised with a granulometer between 5 to 40 microns and can be found in a pink powder form for calcinated products or white for calcinated activated products.

Diatomite is a filter aid for musts and wine. The usage of diatomite requires wearing a protective mask.

  1. Labelling

The label must indicate granulometry, permeability, the specifications of accompanying documents in addition to the storage and safety conditions.

  1. Test trials

3.1.    Odour and taste

Diatomite should not carry any odour or foreign taste to the wine. Put 2.5 g of diatomite in a litre of wine. Mix. Leave 24 hours. Compare the taste to wine not containing any diatomite.

3.2.    Loss during drying

Put 5 g of diatomite in a capsule. Heat in an incubator to 103 ± 2°C. After two hours mass loss should not be more than 1%.

3.3.    Loss through calcinations

Bring the dry residue obtained in point 3.2 to 550°C in a furnace. Weight loss should not be more than 3%.

3.4.    Measure pH level

In a 250 ml container put approximately 10 g of diatomite, then slowly add 100 ml of water to moisten the product and to get a homogeneous suspension. Mix by hand from time to time using a magnetic mixer. After 10 minutes, let the suspension settle and measure the pH. Calcinated diatomites (pink) have a pH level between 5 to 7.5 and activated calcinated diatomites (white) have a pH level between 6 to 10.5.

3.5.    Soluble products in diluted acids

Bring to a boil 10 g of dried diatomite with 20 ml of concentrated hydrochloric acid (R) and 100 ml of water. Collect the diatomite on an ashless filter paper and wash the residue with 100 ml of distilled water. After desiccation at 100-105°C and incineration, separate the filter of insoluble residue, which should weigh at least 9.8 g and constitute 98% of the dried product.

3.6.    Preparation of test solution

In a 500 ml flask, which can be hermetically sealed, put 200 ml of citric acid solution at 5 g per litre bring to pH 3 (R) and 10 g of diatomite.  Put this in a magnetic mixer and mix for 1 hour at a temperature of 20 2°C. Allow to settle and filter by eliminating the first 50 ml of filtrate. Collect at least 100 ml of clear liquid.

3.7.    Iron

On the test solution prepared according to point 3.6, determine the iron following the procedure described in Chapter II. Iron content must be less than 300 mg/kg.

3.8.    Lead

On the test solution prepared according to point 3.6, determine the lead following the procedure described in Chapter II. Lead content must be less than 5 mg/kg.

3.9.    Mercury

On the test solution prepared according to point 3.6, determine the mercury following the procedure described in Chapter II. Mercury content must be less than 1 mg/kg.

3.10 Arsenic

On 4 ml of test solution prepared according to point 3.6, determine the arsenic following the procedure described in Chapter II. Arsenic content must be less than 3 mg/kg.

  1. Storing conditions

Diatomite must be stored in dry well ventilated places or in vacuumed packed sealed bags in a temperate place.

Dimethyl dicarbonate

COEI-1-DMDC Dimethyl dicarbonate (DMDC)

Dimethyl pyrocarbonate

N° SIN = 242

C.A.S  004-525-33-1

EINECS

224-859-8

Chemical formula:

C4H6O5

H3C-O-(C=O)-O-(C=O)-O-CH3

Molecular weight

134.09

 

  1. Object, origin and field of application

 

Antiseptic mainly active against yeast. Synthetic product.

  1. Labelling

 

The name “Dimethyl dicarbonate”, the batch number, the date of expiry, storage temperature (20°C–30°C) and safety precautions must be indicated on the label.

  1. Characteristics

Colourless liquid that decomposes in an aqueous solution. Corrosive for skin and eyes. Toxic in case of inhalation and ingestion.

After dilution in water, CO2 is formed which can be caracterised.

Melting point: 17°C.

Boiling point: 172°C with decomposition.

Density at 20°C: about 1.25.

Infrared spectrum: maximum absorption at 1156 nm and 1832 nm.

 

  1. Characterisation

4.1.    Principle of the method

The sample is mixed with an excess of dibutylamine with which it reacts directly. The excess of amine is determined by back titration.

 

4.2.    Apparatus

4.2.1.  150 ml cylindrical vase

4.2.2.  100 ml graduated test tube

4.2.3.  20 ml pipette

4.2.4.  Glass electrode/reference electrode

4.2.5.  pH metre

4.2.6.  20 ml plunger burette

4.2.7.  Magnetic stirrer

4.2.8.  2 ml disposable syringe.

4.3.    Reagents

4.3.1.  Pure acetone

4.3.2.  Dibutylamine solution [C8H19N] = 1 mole/l

4.3.3.  Weigh 128 g of dibutylamine into a 1 l volumetric flask and fill to the mark with chlorobenzene

4.3.4.  Molar hydrochloric acid solution [HCl] = 1 mole/l

Determine the mass concentration by titration with sodium carbonate. Titre: t

4.3.5.  Anhydrous sodium carbonate, dried in incubator at 110°C.

4.4.    Procedure

Pour about 70 ml of acetone (4.3.1) in a 150 ml cylindrical vase.

Place a cylindrical vase (4.2.1) and introduce 1.0 to 1.3 g (W) of sample by using a disposable syringe (4.2.8) (precision of 0.1 mg).

Add exactly 20 ml of the dibutylamine solution (4.3.2) using a pipette (4.2.3) and shake vigorously.

4.4.1.  Titrate by potentiometry the excess of amine with hydrochloric acid (4.3.4).

  • Consumption of HCl solution = V1 ml.
    1.   Perform a control trial according to 4.4 but without adding the sample.
  • Consumption of HCl solution = V2 ml.

 

4.5.    Result

  • DMDC content should be more than or equal to 99.8%.
  1. DMDC heavy metal, content (expressed in lead), mercury and chloride

 

5.1.    Buffer solution, pH= 3.5 Dissolve 6.25 of ammonium acetate in 6 ml water. Add 6.4 ml of hydrochloric acid and dilute water to 25 ml.

 

5.2.    Solution for trials: Pour 5 ml of buffer solution in a conical flask, 25.0 g of sample and approximately 15 ml of water. Let the sample hydrolyze for 3 days, shaking from time to time. Transfer the solution to a 50 ml graduated cylinder and fill up with water to indicator.

5.3.    Heavy metals

Determine the heavy metal content according to the method in chapter II of the International

Oenological Codex.

The contents of heavy metals must be less than 10 mg/kg.

5.4.    Mercury

Using the solution for trials (5.2) measure the mercury according to the method in chapter II of

the International Oenological Codex.

The contents of mercury must be less than 1 mg/kg.

5.5.    Chloride

Using the trial solution 5.2 (diluted two times compared to initial contents) measure the chloride

according to the method in chapter II of the International Oenological Codex.

The contents of chloride must be less than 3 mg/kg.

 

  1. Determination of arsenic, lead and cadmium by atomic absorption spectrometry

 

6.1.    Determination of arsenic, lead and cadmium by atomic absorption spectrometry

For the determination of arsenic, lead, and cadmium.

Weigh about 100 g of the sample with a precision of 0.1 g in a cylindrical vase.

Add 200 ml of water and 5 ml of pure sulphuric acid (R) and concentrate on a hot plate until the first vapours of sulphuric acid appear.

Re-dilute the solution with water and add 1 ml of pure hydrochloric acid (R). Pour while washing into a 50 ml volumetric flask and bring to mark.

6.2.    Arsenic

Using the trial solution (6.1) determine the arsenic content according to the method in chapter II of the International Oenological Codex.

Arsenic content should be less than 3 mg/kg.

 

6.3.    Lead

Using the trial solution (6.1), determine the lead content according to the method in chapter II of the International Oenological Codex.

Lead content should be less than 2 mg/kg.

6.4.    Cadmium

Using the trial solution (6.1), determine the cadmium content according to the method in chapter II of the International Oenological Codex.

Cadmium content should be less than 0.5 mg/kg.

 

  1. Determination of dimethyl carbonate

Dimethyl carbonate content should be less than 0.2%.

7.1.    Principle of the method

The concentration of dimethyl carbonate is determined by chromatography in gaseous phase. The quantitative evaluation is performed by using methyl-isobutylcetone as an internal standard.

7.2.    Apparatus

7.2.1.  Chromatograph in gaseous phase with a flame ionisation detector and capillary column (apolar type “SE 30” or other; a polar column can also be used such as the Carbowax type 20 M), 50 m x 0.3 mm.

7.2.2.  Data acquisition system.

7.2.3.  A 10 µl quartz needle syringe suitable for an on column injection (injection “on column” (cf. remark 7.7).

7.2.4.  10 ml antibiotic flask with a Teflon stopper that can be sealed with a aluminium capsule with the top part that can be torn off.

7.3.    Internal standard

Ultra pure methyl-isobutylcetone.

7.4.    Procedure

7.4.1.  Weigh about 1 g of the sample at 1 mg (W1 mg) in a flask 7.2.4.

7.4.2.  Add a quantity of internal standard (W2 mg) of methyl-isobuthylcetone (7.3) corresponding to 10 mg/kg after addition (10 μl for example).

7.4.3.  Seal the flask, mix vigorously and inject 0.2 µl.

7.4.4.  Determine the peak area corresponding to the internal standard (F 2) and corresponding to dimethyl carbonate (F 1).

 

7.5.    Result

  • K = Factor for the dimethyl carbonate calculated using reference solutions of this substance preferably prepared in DMDC free from dimethyl carbonate.

7.6.    Remark 1

The sample prepared with the standard should be immediately analysed.

7.7.    Remark 2

A partial decomposition of DMDC can occur when in contact with the metal needles of traditional syringes.

 

  1. Storage

The DMDC must be stored in perfectly watertight containers at a temperature between 20°C and 30°C. Its shelf life is 12 months.

Carbon dioxide

COEI-1-DIOCAR Carbon dioxide

Carbonic anhydride

Carbonei dioxydum

= 44.01

SIN No. 290

  1. Objective, origin and scope of application

 

Carbon dioxide is used in gaseous form, either pure or mixed with nitrogen, in procedures designed to render inert.

  1. Labelling

The label should indicate the nature and purity of the gaz, even when used in mixtures, as well as its safety and storage conditions.

  1. Properties

Carbon dioxide gas is colorless and odorless.  Its aqueous solution has a slightly acidic taste.  At a temperature of 0 °C and under a pressure of 760 mm of mercury, 1 l of carbon dioxide weighs 1.977 g.

At a temperature of 20 °C and under a pressure of 760 mm of mercury, 1 l of water dissolves 878 ml of carbon dioxide, or 1.736 g of CO2.

If a flame is placed in a tube of carbon dioxide, the flame is extinguished.

Fill a 50 ml test tube with carbon dioxide.  Shake with 10 ml of barium hydroxide solution.  A white precipitate will form, which becomes soluble with effervescence by a dilute acetic acid solution (10 pp 100) (R).

  1. Tests

Total purity of carbon dioxide should be 99 parts per 100 by volume.

Testing for and quantitative determination of gaseous impurities can be performed by gas phase chromatography.  The method is described in the Annex.

Carbon dioxide determination can also be accomplished using the following chemical tests.

For the following tests, tubes containing carbon dioxide should be kept at ambient temperature for at least 6 hours prior to sampling.  Volumes to be sampled are calculated by taking temperature and pressure into account, which are indicated here to be 0 °C and 760 mm of mercury.

4.1.    Sulfuric Acid and Sulfur Dioxide

Let 1000 ml carbon dioxide flow, during 15 minutes at a constant speed, into 50 ml of water that has recently been boiled and cooled to room temperature. The feed tube should have an orifice whose diameter is approximately 1 mm and which is immersed to within 2 mm of the bottom of the water container which has a height of 12-14 cm. After the flow of gas is completed, pour the liquid in bucket A of a comparator and add 0.05 ml of methyl orange solution (R).   To bucket B, which contains 50 ml of recently boiled and cooled water, add 1 ml of 0.01 M hydrochloric acid solution, then 0.05 ml of methyl orange solution (R).  The red tint in bucket A should not be darker than that of the liquid in bucket B.

4.2.    Hydrogen Sulfide, Hydrogen Phosphide, Arsine and Organic Reducing Substances

Under the same conditions as those in the preceding test, let 1000 ml of carbon dioxide flow into a mixture of 10 ml of ammoniacal silver nitrate solution (R), 3 ml of concentrated ammonium hydroxide (R) and 15 ml of distilled water.  There should be no clouding or brown color as compared to an identical control solution through which no carbon dioxide gas flowed.

4.3.    Oxygen

For oxygen determination tests (see «Nitrogen»), pierce the stopper of a flask with a 8/10 mm hypodermic needle (take care not to dip the needle into the liquid). This needle will allow gas to escape after bubbling.  Next, insert a second hypodermic needle of the same size to feed the expanding gas into the liquid.  After a minute of bubbling, there should be no significant colorating.  In the presence of oxygen, the liquid will rapidly turn blue and the color become more intense over time.

4.4.    Carbon Monoxide

The limiting carbon monoxide content as determined using the method described in the annex is 10 μl/l/

4.5.    Oil

The limiting oil content as expressed by the quantitiy absorbed by a suitable trap, as described in the technique described in the annex, is 0.1 mg/l.

4.6.    Quantitative Analysis

Place approximately 100 ml of carbon dioxide, measured with precision, in a graduated volumetric flask turned over on a mercury

tank or a graduated gas burette filled with mercury.  Using a curved pipette on the mercury tank or by exerting pressure of mercury using an appropriate device, force the gas into a tube or absorber tank containing a sufficient quantity of an aqueous solution which contains 40 g of potassium hydroxide (R) per 100 ml. Shake for 5 minutes to ensure efficacious contact between the liquid and the gas. Again, feed the gas freed from the aqueous liquid to the graduated flask or the burette.  Read the residual volume at the same temperature and under the same pressure as those at which the sample was measured. Once again, place the residual gas in contact with the alkaline solution and take a second residual volume reading to verify absorption was complete.  There should be no more than 1 pp 100 of non-absorbable gas.

  1. Storage

Carbon dioxide is stored in steel canisters which are painted gray. The strength of these canisters should be periodically checked.

Colloidal silicon dioxide solution

COEI-1-DIOSIL Colloidal silicon dioxide solution

Silica colloidalis solutio

Silicon gel in aqueous dispersion

  1. Objective, origin and scope of application

Colloidal silicon dioxide solutions are aqueous dispersions of silicon dioxide particles which are hydroxylated on the surface and are, therefore, negatively charged.

Silica gel is the dried powder form of silicon dioxide

These preparations are used to clarify wines and are associated with protein-based clarifying agents.

  1. Labelling

The label should indicate the silicon dioxide concentration (for solutions) and its safety and storage conditions.

  1. Properties

Depending on the manner in which they are prepared, acidic solutions are obtained, or alkaline solutions containing sodium ions expressed as Na2O. Alkaline solutions are most often used.

Colloidal silicon dioxide solutions are free from organic compounds.

Their concentration as determined by drying at 110 °C is always equal to or greater than 15 % (m/m) and is most often between 15 and 30 %.

The density of colloidal silicon dioxide solutions at 20 °C (ρ20°C) is given as a function of the concentration C (m/m) by the equation:

These preparations are sold in the form of opalescent or milky liquids with slightly bluish tints, or in gel form.

Dried silica gel is sold in the form of a white, free-flowing powder..

  1. Tests

 

4.1.    The solution or powder should have no disagreeable odour or taste.

4.2.    pH

Depending on the preparation method and on whether acidic or alkaline solutions are employed, the pH should be between 3 and 4 or between 8 and 10.5.

The pH of silicon dioxide powder should be between 5.0 and 7.5 in 10 % aqueous solution.

4.3.    Silicon Dioxide Concentration (Dry Extract at 110 °C)

The weight, P, of the dry residue expressed in g per 100 g of colloidal solution should correspond to within ± 0.5 g of the product's concentration.

For the powder the desiccation loss is determined by drying at 110°C for 4 hours. Weight loss should be not higher than 12 % of the initial weight. Silicon dioxide concentration in the dry powder after desiccation should be above 98%.

4.4.    Alkalinity

For alkaline colloidal solutions, determine the alkalinity of a 5 g sample using 0.1M hydrochloric acid (R) in the presence of 2 drops of methyl orange solution (R). Alkalinity expressed in terms of Na2O for 100 g of product should be less than P/100.

4.5.    Preparing the Solution for Tests

Place a volume of colloidal silicon dioxide solution corresponding to 10 g of dry extract or 10 g of dried silicon dioxide powder in a platinum dish 7 cm in diameter and 2.5 cm high. Evaporate until dry.  Take up the residue after cooling with 5 ml hydrofluoric acid. Evaporate to dryness. Repeat this procedure until the silicon dioxide residue is eliminated. Evaporate to dryness.  Take up the residue using 2 ml concentrated hydrochloric acid (R) and evaporate to dryness. Add 2 ml of concentrated hydrochloric acid (R). Decant in a 50 ml volumetric flask and fill to the mark with distilled water. Safety guidelines for use of concentrated acids have to be respected.

4.6.    Heavy Metals

To 5 ml of the test solution prepared under paragraph 4.5, add 5 ml of water, 2 ml of pH 3.5 buffer solution (R) and 1.2 ml of thioacetamide reagent (R).

No precipitate should form. If a color appears it should be less intense than that of a control prepared as indicated in the Annex and filled to a volume of 25 ml.

Heavy metal content, expressed in terms of lead in dry extract form, should be less than 10 mg/kg.

4.7.    Lead

Using the technique described in the OIV Compendium of international methods for analysis of wine and must, determine the lead content in the test solution (4.5).

The lead content should be less than 5 mg/kg

4.8.    Mercury

Using the technique described in the annex, determine the mercury content in the test solution (4.5).

The mercury content should be less than 1 mg/kg.

4.9.    Arsenic

Using the technique described in the annex, determine the arsenic content in the test solution (4.5).

The arsenic content should be less than 3 mg/kg.

4.10. Methanol

Place 50 ml of colloidal silicon dioxide solution in a 200 ml in a round-bottom flask.  Distill and collect 50 ml of distillate.

Place 1 ml of distillate in a test tube with 4 drops of 50 % (m/m) orthophosphoric acid (R) and 4 drops of 5 % (m/v) potassium permanganate solution (R). Stir and let sit 10 minutes. Decolorize the permanganate with several drops (typically 8) of 2 % (m/v) of anhydrous potassium sulfite (R), while avoiding any excess. Add 5 ml of sulphuric-acid solution of chromotropic acid (R).  Place in a 70 °C water bath for 20 minutes. No violet coloration should appear.

4.11. Formaldehyde

Place 10 ml of the distillate obtained under paragraph 4.10 in a test tube. Add 1 ml of rosaniline hydrochloride solution decoloured with sulfuric acid (R). No pink coloration should appear.

4.12. Medium (d50) and minimum particle size

Medium particle size of silicon dioxide powder should be between 10 and 100 µm measured by laser scattering particle size analyzer after dispersion in demineralized water. Minimum particle size should be above 1 μm.

4.13. Specific surface area (according to BET method)

The BET surface area of silicon dioxide powder is measured by determination of the specific surface area of solid matter by gas adsorption according to ISO 9277:2010.

The specific BET surface area of silicon dioxide powder should be between 300 – 500 m²/g.

  1. Storage

 

Colloidal solutions of silicon dioxide should be stored in hermetically sealed containers away from contaminants and at temperatures of above 0 °C (the product freezes at 0 °C with irreversible precipitation of the silicon dioxide).

Silicon dioxide powder should be stored in sealed bags or boxes protected from off odours or humidity.

D,L-tartaric acid

COEI-1-DLTART D,L-Tartaric acid

D,L-2,3-dihydroxybutanedioic acid

Racemic Acid

Acidum tartaricum

COOH - CHOH - CHOH - COOH

= 150.1

  1. Objective, Origin and Scope of Application

This product is used to eliminate excess calcium from wines and musts under certain conditions.  The calcium racemate that is produced yields particularly insoluble salts.  Its use is subject to certain regulations.

  1. Labelling

The label should cite the purity percentage and storage requirements.

It should also clearly indicate that the product is a racemic mixture of the two isomers D and L of tartaric acid, so as to avoid suggesting that the product is the L-tartaric acid occurring naturally in grapes.

  1. Properties

Colorless, transparent extremely solid crystals having a distinctly acidic taste.  Instantaneous melting point is 206 °C[1].

  1. Solubility

Water at 20 °C

245 g/l

Water at 100 °C

1428 g/l

Alcohol, 95% by vol.

26 g/l

Ethyl ether

14.9 g/l

  1. Identifying Characteristics

5.1.    Verify total solubility in water. A 1% solution exhibits an acidic reaction with respect to methyl orange (R).  This solution has no rotatory power.

5.2.    Add 2 ml of 25% calcium acetate solution (R) to 5 ml of 1% (m/v) solution. An abundant white crystalline precipitate should form instantaneously.  Under these conditions, L(+) tartaric acid (dextrorotatory tartaric acid) yields no precipitate.

5.3.    Add 2 ml 5% potassium acetate solution (R) to 5 ml of 10% (m/v) solution. A crystalline precipitate will form.

  1. Tests

6.1.    Foreign Substances

D,L tartaric acid should be soluble without residue in 10 times its weight of water.

6.2.    Sulfur Ash

As analyzed in 2.0 g D,L tartaric acid, the sulfur ash content should not be greater than 0.2 pp 100.

6.3.    Preparing the Solution for Tests

Dissolve 10 g D,L-tartaric acid in water and fill  to 100 ml with the same solvent.

6.4.    Citric Acid

Add 5 ml of water and 2 ml mercury (II) sulfate solution (R) to 5 ml of the solution prepared for tests under Paragraph 6.3.  Bring to a boil and add several drops potassium permanganate solution (concentration: 2 pp 100) (R).  No white precipitate should form.

6.5.    Chlorides

Add 14.5 ml of water, 5 ml of dilute nitric acid (R) and 0.5 ml of 5 pp 100 silver nitrate solution (R) to 0.5 ml of the solution prepared for tests under Paragraph 6.3.  The solution should meet the chloride limit test described in the Annex.  (Chloride content expressed as hydrochloric acid should be less than 1 g/kg).

6.6.    Iron

Add 1 ml of concentrated hydrochloric acid (R) and 2 ml of 5 pp 100 potassium thiocyanate solution (R) to 10 ml of the solution prepared for tests under paragraph 6.3.  The resulting red coloration should be less intense than that observed in a control prepared using 1 ml of an iron (III) salt solution in a concentration of 0.010 g of iron per liter, 9 ml of water and the same quantities of the same reagents. (Iron content should be less than 10 mg/kg).

Iron content may also be determined by atomic absorption spetrometry in accordance with the method described in the Compendium.

6.7.    Lead

Use the method described in the Compendium to analyze the test solution (6.3). (Content to be less than 2 mg/kg.)

6.8.    Mercury

Using the technique described in the Annex, determine the proportion of mercury in the test solution (6.3). (Mercury content should be less than 1 mg/kg).

6.9.    Arsenic

Using the technique described in the Annex, determine the proportion of arsenic in the test solution (6.3). (Arsenic content should be less than 3 mg/kg).

6.10. Sulfates

Add 18 ml of water, 1 ml hydrochloric acid diluted to 10 pp 100 (R) and 2 ml of 10 pp 100 barium chloride solution (R) to 1 ml of the solution prepared for tests under Paragraph 6.3.  The solution should meet the sulfate limit test described in the Annex.  (Concentration of sulfate expressed as sulfuric acid should be less than 1 g/kg).

6.11. Oxalate

Using the technique described in the Annex, determine the proportion of oxalate in the test solution (6.3). (Oxalate content expressed as oxalic acid should be less than 100 mg/kg after dessiccation).

  1. Quantitative Analaysis

Dissolve a precisely-weighed sample p of approximately 1 g D,L-tartaric acid in 10 ml of water. Titrate with 1M sodium hydroxide solution in the presence of phenolphthalein (R).  Let n be the number of milliliters used.

1 ml of 1M sodium hydroxide solution corresponds to 0.075 g D,L-tartaric acid.

Content, in percent, of D,L-tartaric acid of the product tested: 7.5 n.

Products used in wine-making must contain a minimum of 99 pp 100 D,L-tartaric acid (dry product).

  1. Storage

D,L-tartaric acid should be stored in hermetically sealed containers.


[1] Due to a printing error the value of the melting point has been corrected

Yeast protein extracts

COEI-1-EPLEV Yeast protein extracts (YPE)

  1. Object, origin and scope of application

The proteins of yeast protein extracts mainly come from the cytoplasm of Saccharomyces sp. yeast. These are separated by physical methods after an extraction process that limits their hydrolysis.

The proteins of yeast protein extracts have variable molecular weights and electric charges depending on the manner in which they were obtained and they are capable of flocculation in musts and wines so as to enable clarification and colloidal stabilizing (fining operations).

When the yeast protein extracts come from genetically modified oenological yeasts, they must have been subject to the prior authorisation of the competent authorities.

  1. Labelling

The label must include the following:

the scope of application (must and wine fining)

the conditions of safety and conservation as well as their shelf life

possible admixtures

the manufacturing batch number

the indication of whether the protein extracts come from yeasts obtained through genetic modifications and their modified character if that is the case.

  1. Analysis

3.1.    The YPEs are in the form of powder, generally with micro-granulate, of yellow-to light beige or beige colour, with a slight smell of yeast.

3.2.    The YPEs are water-soluble but not ethanol-soluble.

When in aqueous solution, they precipitate if 1 volume of ethanol is added.

3.3.    Protein determination

3.3.1.  Total proteins

The determination of proteins is to be carried out with the Lowry method as described in appendix 1.

The total protein content of YPEs must be greater than 50% of the dry product.

3.3.2.  Size of proteins

The assessment of the proteins' size or weight is carried out by electrophoresis separation technique SDS-PAGE, as described in appendix 3.

Example of different yeast protein extract profiles with Coomassie blue staining:

  • 1: Size marker
  • 2: Strain 1 Exponential phase
  • 3: Strain 1 Stationary phase
  • 4: Strain 2 Exponential phase
  • 5: Strain 2 Stationary phase
  • 6: Strain 3 Exponential phase (Strain without protease A)
  • 7: Strain 3 Stationary phase (Strain without protease A)
    1.   Protein level greater than 15 KDa

This level is assessed using the gel permeation technique described in appendix 4.

At least 50% of the total proteins must have a molecular weight greater than 15 kDa.

3.4.    Amine Nitrogen

The amine nitrogen content given as glycine, represents 10 to 20% of the dry product maximum

The determination of amine nitrogen may be carried out by the Dinitrofluorobenzene method (DNFB) described in appendix 2.

  1. Testing

4.1.    Desiccation-related losses

Put 5g of YPE in a 70mm silica capsule then place in an incubator at 100-105 °C for 5 hours. The loss of weight must not exceed 15.p.100.

The limiting values indicated below are for dry product.

4.2.    Ash

Incinerate the dry residue at 550-600°C. The ash content must not exceed 8%.

4.3.    Preparation of the solution for testing

Prepare an YPE solution at 10g/l in water.

4.4.    Lead

Determine the lead content of the solution prepared for testing purposes (4.3) with the method described in chapter II of the International Oenological Codex.

The lead content must not exceed 2mg/kg.

4.5.    Mercury

Determine, without evaporating the solution, the mercury content of the solution prepared for testing purposes (4.3) with the method described in chapter II of the International Oenological Codex.

The mercury content must not exceed 1 mg/kg.

4.6.    Arsenic

Determine the arsenic content of the solution prepared for testing purposes (4.3) with the method described in chapter II of the International Oenological Codex.

The arsenic content must not exceed 3 mg/kg.

4.7.    Cadmium

Determine the cadmium content of the solution prepared for testing purposes (4.3) with the method described in chapter II of the International Oenological Codex.

The cadmium content must not exceed 1 mg/kg.

4.8.    Microbiological analysis

4.8.1.  Total aerobic mesophilic flora

Carry out the enumeration with the method described in Chapter II of the International Oenological Codex.

The number must not exceed 10,000 total aerobic mesophilic bacteria in 1g.

4.8.2.  Coliforms

Carry out the enumeration with the method described in Chapter II of the International Oenological Codex.

The number must not exceed 10CFU/g of dry matter.

4.8.3.  Staphylococcus

Carry out the enumeration with a method that is to be described in Chapter II of the International Oenological Codex. Controlled absence of Staphylococcus aureus in a 1 g sample of dry matter.

4.8.4.  Salmonella

Carry out the enumeration with the method described in Chapter II of the International Oenological Codex.

Controlled absence of salmonella in a 25 g sample of dry matter.

4.8.5.  Escherichia coli

Carry out the enumeration with the method described in Chapter II of the International Oenological Codex.

Controlled absence of Escherichia coli in a 25 g sample of dry matter.

4.8.6.  Lactic bacteria

Carry out the enumeration with the method described in Chapter II of the International Oenological Codex.

The number must not exceed 103 CFU/g of dry matter.

4.8.7.  Mould

Carry out the enumeration with the method described in Chapter II of the International Oenological Codex.

The number must not exceed 50 CFU/g of dry matter.

4.8.8.  Yeasts

Carry out the enumeration with the method described in Chapter II of the International Oenological Codex..

The number must not exceed 102 CFU/g of preparation.

4.9.    Efficiency test of types for the fining of musts and wines

4.9.1.  Principle

The aim is to determine the most compatible quantity needed to achieve fast clarification and colloidal stability of the wine.

4.9.2.  Product:

Musts or wines to undergo fining

4.9.3.  Protocol:

4.9.3.1. YPE solution at 2%

Dissolve 2 g of YPE in 100 ml of distilled water.

4.9.4.  Fining test

Place 100 ml of must or wine in as many 100 ml tubes as determinations selected. In practice, the comparison of 4 determinations is sufficient, i.e. five 100 ml tubes, including the control.

Add 0 ml (control), 1.5 ml, 2 ml, 2.5 ml of the YPE solution (4.9.3.1) for a red wine and 0.5 ml, 1 ml, 1.5 ml of YPE solution for a white or rosé must or for a white or rosé wine. These quantities correspond respectively to the final determinations of 0 mg/l, 200 mg/l, 300 mg/l, 400mg/l and 500 mg/l for a red wine and to 0 mg/l, 100 mg/l, 200 mg/l and 300 mg/l for a white or rosé must or for a white or rosé wine.

  • Homogenise each tube after admixture of the YPE solution (cover the tubes with a film and shake 2 to 3 times by hand).

Note the turbidity increase speed and the apparition of flakes every 10 minutes for 30 minutes. After 8 hours compare each test and monitor:

  • Turbidity
  • the volume of lees,
  • the colouring intensities,
  • the organoleptic quality,
  • the colloidal stability by heating to 80°C for 20 minutes in a water bath or incubator at 100 °C and rapid cooling under a stream of cold water.
  1. Conservation

The yeast protein extracts have a 3 year shelf-life in closed packaging if stored in temperate facilities and kept away from humidity.

  1. Bibliography
  • Feuillat M. (1986). Autolysats de levures à usage oenologique et leur procédé de fabrication. France.
  • Feuillat M. (1987). "Préparation d'autolysats de levures et addition dans les vins effervescents élaborés selon la méthode champenoise." Rev. Fr. Oeno 109: 17-27.
  • Charpentier C. and Feuillat M. (1992). Yeast autolysis. Wine microbiology and biotechnology.F. G.H. Chur, Harwood Academic Publisher.
  • Charpentier C. and Freyssinet M. (1989). "The mechanism of yeast autolysis in wine." Yeast: S1 S48.
  • Charpentier C. (2000). "Yeast autolysis and yeast macromolecules? Their contribution to wine flavor and stability." Am. J. Enol.Vitic. 51: 271-277.
  • Charpentier C., Caillet M.M, Feuillat M. (2006) Essais de collage de moûts blancs et de vins rouges avec un extrait protéique levurien : comparaison avec les colles traditionnelles. Rev. Œnologues 120, juillet 2006.

Appendix 1: Lowry Method

  1. Introduction

The proposed method is that of LOWRY (LOWRY et al. 1951) but can be replaced by other methods such as that of BRADFORD (1976).

Bradford, M. M. (1976) A Rapid and Sensitive Method for the Quantitation of Microgram Quantities of Protein Utilizing the Principle of Protein-Dye Binding. Anal. Biochem. 72:248-254.

  1. Scope

The LOWRY method is derived from that of Biuret: in an alkaline medium, copper ions form with proteins a pink-purple copper complex characteristic of peptide bonds. The method is 100 times more sensitive than the Biuret method.

  1. Definition

The LOWRY method consists in copper complexing, in an alkaline medium, approximately a quarter of the amino acids constituting the proteins. The Folin Ciocalteu reagent (phosphomolybdic reagent) reacts with the aromatic amino acids of the proteins.

The absorbance of the complex thus formed is determined spectrophotometrically at 750 nm. The main drawback of this method is the interference of the Folin reagent with other compounds (EDTA, dithioerythritol, oxidized glutathione, etc.).

The determination of the water-soluble proteins is performed by comparison with a standard curve plotted on the basis of protein solutions of known concentrations. (BSA type).

  1. Reagents and Products

Solution A: solution of 2% Na2CO3 in 0.1 M NaOH containing 0.02% (500 mL) of sodium tartrate (or potassium).

Solution B: solution of 5% CuSO4.5 H2O (100 mL).

Reagent C: produce extemporaneously 50 mL of solution A + 1 mL of solution B.

FOLIN-CIOCALTEU reagent: commercial solution.

Standard solution of Bovine Serum Albumin (BSA).

  1. Equipment

Test tubes

Class A pipettes

Micropipettes

Plastic film for sealing

Visible Spectrophotometer

  1. Procedure

6.1.    Standard range of proteins: preparation and determination

The standard range is made using a standard solution of 0.5 mg.mL-1 of BSA.

In graded 100-mL flasks, prepare solutions of BSA containing 0, 100, 200, 300, and 400 μg.mL-1 of BSA from the stock solution.

Dispense into test tubes 0.6 mL each dilution. A control tube contains only 0.6 mL of distilled water

Thoroughly mix each solution by inversion.

Add to each tube:

3 mL of reagent C

Close the tube with the plastic wrap and homogenise by inversion

Let the tubes stand for 10 minutes before adding 0.3 mL of Folin reagent.

Homogenize.

Wait 30 minutes in the dark and then measure the absorbance at 750 nm by adjusting the zero of the distilled water solution (concentration in BSA 0 μg. mL-1).

Plot the curve OD = f (protein concentration).

6.2.    Determination of proteins in the Yeast Protein Extract

In 3 test tubes add successively:

0.6 mL of extract diluted to 1/20th, 1/30th, and 1/40th (30, 20 and 15 μl in 0.6 mL)

3 mL of reagent C; homogenize after sealing the tubes and let them stand for 10 minutes.

0.3 mL of Folin reagent, homogenise.

Wait 30 minutes in the dark

Measure the absorbance at 750 nm.

  1. Calculations

Note: If the absorbance values are low, recommence the procedure using smaller dilutions of yeast protein extract (1/10th, 1/5th, 1/4 i.e. 60, 120 and 150 μl in 0.6 mL).

Determine by comparing with the standard curve the protein concentration in the YPE in μg.mL-1 then in mg.mL-1 by direct reading or by using the regression line of the standard curve (specify on the standard curve the equation for the line and the correlation coefficient).

Appendix 2: Dinitrofluorobenzene method

  1. Introduction

 

This method is used to quickly determine the amino nitrogen in a biological solution compared with a standard range produced with a solution of glycine.

  1. Scope

Oenological products of plant or animal origin

  1. Definition

Dinitrofluorobenzene (DNNFB) reacts with free NH2 functions contained in the amino acids to give a bright yellow compound determined by colorimetry at 420 nm. The reaction takes place at pH> 9.3.

  1. Reagents and Products

Reagents:

  • Borax or sodium tetraborate
  • 10 M Hydrochloric acid dinitrofluorobenzene
  • Glycine
  1. Equipment:
  • haemolysis tubes
  • micropipettes
  • Visible spectrophotometer
  • Water bath at 60°C
  1. Sampling

 

Prepare a solution of 5% sodium tetraborate in pure water

Prepare a solution with DNFB: introduce 130 μl of DNFB in 10 mL of 95% pure ethanol.

Prepare a solution of hydrochloric acid 2M

Produce a standard range from a stock solution of glycine with 2 g/l (M = 75.07 g) e.g. 0.50 mg/l, 100 mg/l, 200 mg/l, 500 mg/l

Prepare a solution with 2 g/l of the product to be titrated

  1. Procedure

 

In a test tube, insert:

  • 380 μl of 5% Borax
  • 20 μl of the sample to be titrated
  • 20 μl of the DNFB solution perform in identical fashion with the glycine range

Stir and place in water bath at 60°C for 30 min

Add 3 mL of HCL 2M

Stir and read the specific absorbance at 420 nm for the sample

Produce a calibration curve with the Glycine range

  1. Results

Plot the value of absorbance at 420 nm for the sample on the calibration curve

The results are expressed in g/l of Glycine.

 

Appendix 3: Protein separation by SDS-PAGE

  1. Introduction:

SDS-PAGE (polyacrylamide gel electrophoresis) is a variant of electrophoresis commonly used to separate proteins by their molecular weight

  1. Scope

Evaluation of the molecular weight of proteins of plant or animal origin. This method can be applied to all products of biological origin and winemaking products containing proteins.

  1. Principle

The determination of the molecular weights of proteins is carried out by SDS-PAGE using the Laemmli method (1970). This technique enables the separation of proteins according to their molecular weight using Sodium Dodecyl Sulphate or SDS, a strongly negatively charged molecule, which standardizes their charges and make them lose their native three-dimensional structure. The migration rate of the whole SDS / denatured molecule depends only on the molecular weight of the proteins. Prior to protein denaturation with SDS, the disulphide bonds of the proteins must be reduced by 2-mercaptoethanol.

The migration medium consists of a polyacrylamide gel.

The gel is composed of two parts. A concentration gel which, as its name suggests, allows the proteins to concentrate before they migrate into the separating gel underneath.

The concentration gel contains 5% of acrylamide-bisacrylamide, while the separating gel contains 12%.

The migration takes place in the electrophoresis buffer chilled to 12°C and stirred for about 1 h 30 at a voltage of 80 V for the concentration gel and for nearly 3 hours at 170 V for the separating gel.

Once de-moulded, the gel undergoes staining to reveal the protein bands. The molecular weights of the bands can be measured using known size markers that have migrated with the samples. For example, using a marker sold by Sigma under the name of Molecular Weight Standard Mixture with the following sizes: 15, 25, 35, 50, 75, 100 and 150 Kda.

  1. Reagents and Products

4.1.    Denaturation buffer

  • Buffer Tris Hcl 0.125 M pH 6.8
  • distilled water;
  • SDS to 4%
  • 2-mercaptoethanol to 10%;
  • bromophenol blue to 0.2%
  • pure glycerol
  • Complete with distillated water

4.2.    Separating gel, preparation for 30 mL

  • 7.50 mL of acrylamide/bis-acrylamide
  • 11.25 mL Tris/Hcl buffer to 0,75 M pH 8.8
  • 0.30 mL of SDS to 10%
  • 10.95 mL of distilled water

30 microlitres of TEMED for polymerisation

after stirring, add 300 microlitres of ammonium persulfate to 20%

4.3.    Concentration gel, preparation for 10 mL

  • 1.25 mL of acrylamide/bis-acrylamide
  • 1.25 mL Tris/Hcl buffer to 0,25 M pH 6.8
  • 0.10 mL of SDS to 10%
  • 7.4 mL of distilled water
  • for the polymerisation, add 40 microlitres of TEMED
  • after stirring, add 100 microlitres of ammonium persulfate to 20%

4.4.    Migration buffer, preparation for 1 litre

  • 12.5 mL Tris buffer 25mM pH 8,3
  • 14.4 g of glycine
  • 977.5 mL of distilled water
  • 10 mL of SDS to 10%
  1. Equipment

Electrophoresis equipment for

  • the plates
  • the clamps
  • the seal
  • the comb
  • the spacers
  1. Sampling

6.1.    Denaturing the proteins of products

The samples are treated in the denaturing buffer, prepared just before the denaturing process.

50 microlitres of samples are mixed with 50 microlitres of denaturing buffer.

The mixture is then heated to boiling point for 4 minutes in order to promote protein denaturation.

  1. Procedure

7.1.    Preparation of plates

The electrophoresis plates are cleaned before use with water (and soap if necessary) and then with 70% alcohol.

Wipe the plates with a paper towel, leaving no fibres on the surfaces where the gel will be poured.

Place the seal on the round-edged plate.

Install the spacers and the second glass plate.

The assembly is then consolidated with clamps.

7.2.    Pouring the separating gel

As soon as it has been prepared, the separating gel is poured between two plates using a pipette.

To avoid the presence of bubbles in the gel, the assembly is tilted during filling.

The gel is then covered with distilled water to obtain a perfectly horizontal surface.

7.3.    Pouring the concentration gel

Remove the distilled water from the top of the separating gel

Holding the assembly tilted, fill it with the concentration gel to the upper level of the glass plates.

Put the comb in place to form wells in the concentration gel.

7.4.    Sample deposits

Remove the comb

Place the plates and migration tanks in the electrophoresis tank.

Fill the tanks with the migration buffer starting with the upper and then the lower part.

Add 50 microlitres of denatured protein sample in each well using a syringe and the submarine technique.

Also place a size marker in each of the wells located around the edges in order to frame the well containing the samples.

Once the deposits have been made, the migration is initiated relatively quickly to prevent the spread of the deposits

7.5.    Starting and stopping the electrophoresis

The duration of the electrophoresis depends on several factors:

The generator used, the thickness of the gel, the amount of buffer used, its dilution, etc.

Close the lid of the tank

Check that the generator is switched off or disconnected

Connect the wires of the generator lid

maintain the temperature at 12°C

Connect the generator to the mains

Start the generator on the selected voltage: 80 volts for 1:30 for the concentration gel then 170 volts for about 3 hours for the migration in the separating gel

Stop the electrophoresis when the bromophenol blue reaches the bottom edge of the plates.

Switch off the generator and disconnect the power

Disconnect the wires from the lid

Open the electrophoresis tank

Remove the gel on its support

  1. Results

The bands perpendicular to the path of migration for each molecule of protein can be revealed using several types of staining. The intensity and thickness of the bands depend on the protein concentration.

The size marker is used to directly assess the molecular weight of the proteins in each band.

8.1.    Staining of electrophoresis gels

Several types of staining can be applied to characterise the proteins present as precisely as possible.

Coomassie blue staining

After migration, the electrophoresis gels are immersed in a Coomassie blue staining solution (0.025% Coomassie Blue R250, 40% methanol, 7% acetic acid) overnight.

The next day the electrophoresis gels are soaked for 30 minutes in an initial de-staining bath (40% methanol, 7% acetic acid) to remove the excess dye. They are then placed in a second bath (5% methanol, 7% acetic acid) which is changed regularly until a virtually colourless background is obtained. The staining and de-staining steps are carried out while stirring at room temperature.

The gels are stored in distilled water before being scanned for analysis.

8.2.    Staining with silver nitrate

Staining with silver nitrate can detect smaller amounts of protein than Coomassie blue staining. The products used for this staining are provided by Biorad and form part of the Silver Stain Plus kit.

Once electrophoresis has been completed, the gel is placed in a bath of 400 mL of fixing solution (50% methanol, 10% acetic acid, 10% fixative enhancer concentrate (kit), 30% distilled water) for 20 min while stirring at room temperature.

The gel is then rinsed twice with 400 mL of distilled water for 10 min to remove any acetic acid which may impair the staining step.

Staining is performed with 100 mL of a solution prepared as indicated below:

In a large beaker, place:

  • 35 mL of distilled water
  • 5 mL of "Silver Complex" solution
  • 5 mL of "Reduction Moderator" solution
  • 5 mL of "Image development" reagent

Once these products have been well mixed and just before use, 50 mL of the "Developer Accelerator" solution at room temperature are added to the beaker. The preparation is then poured over the gel in the staining dish. After a period of 20 to 60 minutes, depending on the sample and its concentration, brownish bands appear.

The reaction is then stopped with a solution of 5% acetic acid for at least 15 min, then the gel is placed for about 5 min in ultrapure water. The gels are then ready to be scanned to determine the molecular weights of the protein bands.

8.3.    Staining of glycoproteins

 

This method is used to express the presence of glycoproteins in yeast-type products. It is performed using the "GelCode® Glycoprotein Staining" kit marketed by Pierce Biotechnology.

After electrophoresis, the gel is fixed by immersion in a bath of 300 mL of 50% methanol for 30 min while being stirred.

Wash the gel in a bath containing 300 mL of 3% acetic acid for 10 min. Repeat this step once. (The staining can be stopped after this step by placing the gel in distilled water overnight).

The gel is then covered with 25 mL of "Oxidizing Solution" while being stirred for 15 min.

The gel is then washed 3 times with 300 mL of 3% acetic acid for 5 min.

A solution of 25 mL of GelCode® Glycoprotein Staining is placed on the gel for 15 min while being stirred.

Add 25 mL of "Reducing Solution" while gently stirring for 5 min.

Wash the gel thoroughly with a solution of 3% acetic acid. The glycoproteins appear as magenta bands. The gel can be stored in a solution of 3% acetic acid before being scanned.

Appendix 4: Gel permeation chromatography

  1. Introduction

The proposed method is a molecule separation method. This type of chromatography is also called gel filtration or exclusion chromatography.

  1. Scope

The polymer profiles are studied in the biological products using gel permeation chromatography on a column optimised for protein analysis. A double detection at 280 nm/214 nm is used to monitor the elution of molecules containing amino acids with aromatic rings and peptide bonds.

  1. Definition

Gel permeation chromatography allows the separation of molecules depending on their size and shape using a column containing porous granular gel. Large molecules (with a diameter greater than that of the pores) are excluded and eluted first at the dead volume (Vm or V0). Small and medium sized molecules are eluted later, their migration being impeded by their inclusion in the gel. The solutes are therefore eluted in reverse order of molecular weight. There is a linear relationship between the elution volume and the molecular weight logarithm.

  1. Reagents and products

NaH2PO4,2H2O

Na2HPO4,2H2O

NaCl

NaOH 10 M

Compound

Molecular weight in kDa

Bovine albumin

66

Egg albumin

45

Glyceraldehyde 3 phosphate dehydrogenase

36

Bovine carbonic anhydrase

29

Bovine trypsinogen pancreas

24

Soy trypsin inhibitor

20

Lactalbumin

14.2

  1. Equipment

GE Healthcare chromatography column: Superdex 200 (diameter 10 mm x length 300 mm)

Cellulose-ester filters with porosity: 0.22 μm

  • Cup
  • 2L beaker
  • 1L volumetric flask
  • 0.45 μm membranes for aqueous solution
  1. Procedure

6.1.    Chromatography buffer and conditions

In a cup, weigh:

  • NaH2PO4, 2 H2O = 1.56 g
  • Na2HPO4, 2 H2O = 1.58 g
  • NaCl = 14.63g

Decant into a beaker containing 0.9 litres of ultrapure water. The pH of this solution should be approximately 6.5. Bring it to pH = 7.2 using NaOH 10 M.

Decant into a 1L volumetric flask and make up to 1L with ultrapure water. Filter through 0.45 μm membrane for an aqueous solution.

The flow is set at 0.6 mL/min.

6.2.    Preparing the samples

To analyse a product in a powder form for example, dilute 1 g in 100 mL of ultrapure water. Filter the sample through a 0.22 µm cellulose-ester filter

6.3.    Column calibration

To calibrate the column, plot a curve from the log of the molecular weight of the molecular weight solutions according to the retention time.

Inject the sample solution according to this.

  1. Results

Inject the molecular weight solution mixture as indicated in point 7.3. Plot the curve of the log of the solutions’ molecular weight according to the retention time. Determine the molecular weights of the product’s peaks by referring to this curve.

Selective plant fibres

COEI-1-FIBVEG Selective plant fibers

  1. Object, origin and scope of application

 

Selective plant fibers come from the edible parts of certain plants, generally of cereal origin. The plant fibers undergo series of mechanical treatments and extractions that concentrate the active complex without damaging the structure of the plant fiber. The objective is to increase the adsorption capacity.

The activated plant fibers fix some pesticide residues that may be present in wine and ochratoxin A. They are used during the filtration of wines.

  1. Labelling

The label should contain the following indications:

  • the name or sales denomination,
  • the statement ‘Product for oenological use,
  • the batch number and expiry date,
  • the storage conditions,
  • the origin and composition of the fibers,
  • the name or company name of the manufacturer,
  • the address of the manufacturer,
  • the net quantity.

 

  1. Characteristics

The product is insoluble and comes in the form of a very fine powder.

  1. Composition

The selective plant fibers contain a minimum of 90% (in mass) insoluble parietal compounds (NDF fraction) in total, determined by the Van Soest method in Annex 1.

  1. Trials

 

5.1.    Desiccation-related loss

Place 5 g of product in a desiccator at 90 °C for 15 minutes. The weight loss should not exceed 8% of the initial weight.

All of the limits set below relate to dry products.

 

5.2.    Ashes

Without going above 550 °C, progressively incinerate the residue left in the determination from the dessication loss.

The weight of the ashes should be less than 1%.

 

5.3.    Products soluble in aqueous solution

Place 10 g of selective plant fibers in a 250 mL container then pour  100 mL of water slowly while mixing by hand to obtain a homogeneous suspension. Collect the selective plant fibers on a filter and rinse the container with distilled water to pick up the residues from the selective plant fibers. After 48 h at a temperature of 45 °C, the loss in soluble products should not exceed 3% of the initial dry matter weight.

 

5.4.    Contaminant adsorption trial

5.4.1.  Pesticides

The capacity for adsorption (KF) of 2-chloro-N-(4’-chlorobiphenyl-2-yl) nicotinamide (Boscalid) by the selective plant fiber, determined according to the method described in Annex 2, should be over or equal to 1000 mg/kg for a dose of 2 g/L selective plant fibers.

5.4.2.  Ochratoxin A

For a 2 g/L dose of selective plant fibers, their capacity for adsorption (KF) of ochratoxin A (OTA), determined according to the method described in Annex 3, should be over or equal to 1200 mg/kg.

 

5.5.    Iron

Quantification by atomic absorption spectrometry according to the method described in chapter II of the International Oenological Codex.

The iron content should be below 100 mg/kg.

5.6.    Copper

Quantification by atomic absorption spectrometry according to the method described in chapter II of the International Oenological Codex.

The copper content should be below 25 mg/kg.

5.7.    Lead

Quantification by atomic absorption spectrometry according to the method described in chapter II of the International Oenological Codex.

The lead content should be below 5 mg/kg.

5.8.    Mercury

Quantification by atomic absorption spectrometry according to the method described in chapter II of the International Oenological Codex.

The mercury content should be below 1 mg/kg.

5.9.    Arsenic

Quantification by atomic absorption spectrometry according to the method described in chapter II of the International Oenological Codex.

The arsenic content should be below 1 mg/kg.

 

5.10. Cadmium

Quantification by atomic absorption spectrometry according to the method described in chapter II of the International Oenological Codex.

The cadmium content should be below 1 mg/kg.

 

5.11. Salmonella

Salmonella should be absent in 25 g of selective plant fibers.

Proceed with counting according to the method described in Chapter II of the International Oenological Codex.

5.12. Bacteriological control

Proceed with counting according to the method described in Chapter II of the International Oenological Codex.

The total viable microorganism content should be less than 3·104 CFU/g.

5.13. Escherichia Coli

Proceed with counting according to the method described in Chapter II of the International Oenological Codex.

Absence should be checked on a 1-g sample.

5.14. Yeasts

Proceed with counting according to the method described in Chapter II of the International Oenological Codex.

Limit: 103 CFU/g of preparation.

5.15. Moulds

Proceed with counting according to the method described in Chapter II of the International Oenological Codex.

Limit: 103 CFU/g of preparation.

 

Annex 1: Method of analysis of insoluble parietal compounds (NDF fraction) according to the so-called 'crucible' method (Van Soest)

 

  1. Principle

Analysis of plant-cell-wall components (hemicellulose, cellulose and lignin) after solubilisation of proteins and starches by treatment with neutral detergent (ND).

  1. Apparatus
    1.     Balance with precision of 0.001 g
    2.     Drying oven
    3.     Oven
    4.     Desiccator
    5.     Filter crucibles (40-100 µm porosity)
    6.     Fibertec-type (or equivalent) analyser, i.e. closed (semi-automatic / automatic) apparatus making it possible to treat up to 6 crucibles at the same time, including dispensing of reagents, extraction and its phases of boiling, rinsing and filtration.
  1. Reagents
    1.     Heat-stable α-amylase, e.g. (Ref.: A3306) Sigma Chemical Co.
    2.     Neutral detergent solution (NDS); for 5 L solution:
  • sodium lauryl sulphate (CH3(CH2) 11OSO3Na, p. m.: 288.4 ) – 150 g,
  • EDTA – disodium ethylenediaminetetraacetate (C10H14N2Na2O8·2H2O, p. m.: 372.23) – 93.05 g,
  • disodium tetraborate decahydrate (Na2B4O7·10H2O, p. m.: 381.37) – 34.05 g,
  • disodium hydrogen phosphate dihydrate (Na2HPO4·2H2O, p.m.:  177.99) – 22.8 g,
  • triethylene glycol (C6H14O4, p.m.: 150.17) – 50 mL.
  1. Procedure
    1.     Insoluble fibers in the neutral detergent

Prepare the crucibles.

For each sample of plant fibers, prepare 2 crucibles:

Crucible for isolating insoluble components (NDF)

Weigh 2 g plant fibers in a clean, dry crucible.

Make a note of the weight with a precision of 0.001 g (W = weight of the sample).

Crucible for measuring the ashes content of the sample

Weigh 1 g plant fibers in a clean, dry crucible.

Make a note of the weight with a precision of 0.001 g (W = weight of the sample).

Insert the crucibles (into the Fibertec-type system).

Add 100 mL of NDS solution (1.3.2) to each sample at room temperature.

Add 50- μl α-amylase (1.3.1).

Bring to and maintain at boiling point as follows:

heat for 5-10 minutes, until boiling; reduce the temperature and add an anti-foaming agent (such as octanoic acid) as it starts to boil; adjust the temperature to maintain boiling and continue to heat for 60 minutes.

After 1 hour of extraction, stop heating and remove the NDS solution using a suction system.

Rinse and filter.

Add 40 mL hot water (90-100 °C) to each crucible, mix/stir the samples and leave to infuse for 2 minutes.

filter under vacuum.

Repeat this operation 4 times.

Add acetone to each crucible and leave to infuse for 2 minutes. Filter under vacuum.

Repeat this operation 2 times.

Remove the crucibles.

Rinse crucible (A) twice with hot water (90-100 °C) and place at 105°C for 12 hours.

Place crucible (B) at 105 °C for 12 hours, cool in the desiccator and weigh, which gives W1

(W1 = crucible + NDF fraction+ total ashes [TA]).

Then place it at 500 °C for 3 hours, cool in the desiccator and weigh, which gives W4

(W4 = crucible + total ashes [TA]).

4.2.    Determination of the dry matter (DM) content

Weigh, with a precision of 0.001 g, a watch glass (WDM).

Weigh, with a precision of 0.001 g, 2 g plant fibers in a clean and dry watch glass, which gives W2

 (W2 = weight before drying).

Place the watch glass at 105 °C for 16 hours, leave to cool in the desiccator and weigh, which gives W3

(W3 = weight after drying).

  1. Calculations
    1.     Determination of dry matter (DM)

 

5.2.    Determination of the insoluble fraction of fibers in the neutral detergent fiber (NDF)

Annex 2: Measurement of the pesticide adsorption capacity by selective plant fibers

  1. Principle

 

The aim is to determine the adsorption capacity by selective plant fibers of a fungicide used for the treatment of vines, whose trade name is Boscalid.

  • IUPAC chemical name: 2-chloro-N-(4’-chlorobiphenyl-2-yl) nicotinamide
  • Chemical formula: C18H12CL2N2O
  • CAS No.: 188425-85-6

 

The proposed method refers to the determination of the Freundlich isotherm. 

 

  1. Safety precautions

 

Pesticides are potentially toxic and should be handled under safe conditions protecting the analysts, especially when preparing stock solutions from pure analytical standards. Operators should protect their hands and eyes, and work under an extraction hood.

 

  1. Apparatus

 

3.1.    Everyday laboratory glassware: calibrated flasks, pipettes, flasks

3.2.    Balance with precision of 0.001 g

3.3.    Magnetic stirrer

3.4.    Centrifuge

  1. Reagents

 

4.1.    2-chloro-N-(4’-chlorobiphenyl-2-yl) nicotinamide analytical standard in powder form with a purity of > 99%

4.2.    Quality acetone for residue analysis

4.3.    Preparation of 2-chloro-N-(4’-chlorobiphenyl-2-yl) nicotinamide standard solutions:

4.3.1.  1000-mg/L stock solution of 2-chloro-N-(4’-chlorobiphényl-2-yl) nicotinamide in acetone: dissolve precisely 50 mg pure analytical-standard powder in 50 mL acetone.  The stock solution may be kept at -20 °C for up to a year

4.3.2.  100-, 10- and 1-mg/L working solutions of 2-chloro-N-(4’-chlorobiphényl-2-yl) nicotinamide in acetone: use successive dilutions of the stock solution in acetone. Working solutions may be kept at -20 °C for up to 6 months.

 

  1. Procedure

 

A summary of the conditions used for the preparation of control wines and test wines is provided in Table 1 (see below).

5.1.    Preparation of control wines

Prepare each control wine from a wine free from pesticides, adding 9 increasing concentrations of 2-chloro-N-(4’-chlorobiphenyl-2-yl) nicotinamide to the control in order to obtain, for example, 500 mL of each supplemented wine (see Table 1). Carry out the additions using the working standard solutions (2.4.3.2).  Conduct 2 repetitions per concentration. 2-chloro-N-(4’-chlorobiphenyl-2-yl) nicotinamide is then analysed in the 9 control wines, in order to obtain the initial concentrations measured.

5.2.    Preparation of test wines

Place the 9 wines supplemented with pesticide (2.5.1) in contact with the selective plant fiber.

Procedure:

Add 0.4 g selective plant fibers to a small volume of control wine supplemented with 2-chloro-N-(4’-chlorobiphenyl-2-yl) nicotinamide, then pour the mixture into a 200-mL calibrated flask and make up to 200 mL with this same wine (the dose of plant fiber is 2 g/L).

Leave this wine in contact with the plant fibers in a stoppered flask with the magnetic stirrer on for 45 minutes. Centrifuge for 5 minutes at 4500 rpm (3600 g). Separate the supernatant from the centrifugation pellet and proceed with the analysis of the 2-chloro-N-(4’-chlorobiphenyl-2-yl) nicotinamide residues in order to obtain the residual concentrations measured in the supernatant. Repeat this operation for the 9 control wines supplemented with 2-chloro-N-(4’-chlorobiphenyl-2-yl) nicotinamide (2.5.1). Conduct 2 repetitions per concentration.

 

Table 1: summary of the conditions for the determination of the capacity for adsorption of 2-chloro-N-(4’chlorobiphenyl-2-yl) nicotinamide

Contact time

45 minutes

Wine used for testing

Wine free from pesticides (prior analysis) 

Selective plant fibers

Dose of 2 g/L (test wines)

Absence (control wines)

Pesticide molecule tested

2-chloro-N-(4’chlorobiphenyl-2-yl) nicotinamide (common name: Boscalid)

Concentrations of 2-chloro-N-(4’chlorobiphenyl-2-yl) nicotinamide added

5 μg/L

15 μg/L

30 μg/L

60 μg/L

120 μg/L

240 μg/L

480 μg/L

960 μg/L

1500 μg/L

Number of repetitions

2

Centrifugation – parameters

Room temperature

4500 rpm (round 3600 g) for 5 minutes

Method of analysis of 2-chloro-N-(4’-chlorobiphenyl-2-yl) nicotinamide residue

Determination of pesticide residues in wine after extraction using the QuEChERS method (OIV-MA-AS323-08-type II), then analysis of the extracts by UPLC/MS/MS 

 

  1. Calculations

 

The determination of the capacity for adsorption of 2-chloro-N-(4’-chlorobiphenyl-2-yl) nicotinamide is calculated using the following Freundlich equation:

where

  • KF = the selective plant fiber's capacity for adsorption of the molecule in µg/g of fiber,
  • n = the affinity of the selective plant fiber for the molecule,
  • CRes = the residual concentration of chloro-N-(4’chlorobiphenyl-2-yl) nicotinamide measured in the wine, in μg/mL, after contact with the selective plant fibers,
  • CAds = the concentration adsorbed by the selective plant fibers, in μg/g:
  • CAds in µg/g = CAds in μg /L / 2 (where the adsorbent dose = 2 g fiber/L wine),
  • CAds in μg/L = the initial concentration measured in the supplemented control wine, in μg/L, before contact with the selective plant fibers CRes in μg/L.

Based on the residual concentrations (μg/L) measured, the concentrations of adsorbed 2-chloro-N-(4’-chlorobiphenyl-2-yl) nicotinamide (μg/L) are thus calculated for each initial concentration and

the regression curve Log CAds = 1/n Log CRes + Log KF is traced.

The Freundlich adsorption regression of the pesticide by the selective plant fiber thus allows Freundlich's two constants to be calculated: the adsorption capacity in μg/g (KF) and the affinity of the fiber for pesticide (n). The equation of the line y = ax + b gives the slope a =1/n and b = Log KF.

 

E.g. Freundlich isotherm for 2-chloro-N-(4’chlorobiphenyl-2-yl) nicotinamide

 

Freundlich isotherm for 2-chloro-N-(4’chlorobiphenyl-2-yl) nicotinamide by semective plant fibers

 

As such, in the below example, the following may be calculated:

  • b = Log KF = 3.1871, where  KF =10b = 1538.54
  • a = 1/n = 0.9624, where n =1 /a = 1.04

The affinity (n) of the selective plant fiber for 2-chloro-N-(4’-chlorobiphenyl-2-yl) nicotinamide is 1.04 and the adsorption capacity (KF) of 2-chloro-N-(4’-chlorobiphenyl-2-yl) nicotinamide by the selective plant fibre is 1538.54 µg/g or mg/kg of fiber.

 

Annex 3: Measurement of the ochratoxin A adsorption capacity by selective plant fibers

 

  1. Principle

 

The aim is to determine the adsorption capacity by selective plant fibers of a certain mycotoxin:

  • Commercial name: Ochratoxin A (OTA)
  • IUPAC chemical name: N-{[(3R)-5-chloro-8-hydroxy-3-methyl-1-oxo-3,4-dihydro-1H-isochromen-7-yl] carbonyl}-L-phenylalanine
  • Chemical formula: C20H18ClNO6
  • CAS No.: 303-47-9

 

The proposed method refers to the determination of the Freundlich isotherm.

 

  1. Safety precautions

 

Ochratoxin A is a toxin classified by the International Agency for Research on Cancer (IARC) as category 2B (possibly carcinogenic to human). It should therefore be handled under safe conditions protecting the analysts, especially when preparing stock solutions from pure analytical standards. Operators should protect their hands and eyes, and work under an extraction hood.

 

  1. Apparatus
    1.     Everyday laboratory glassware: calibrated flasks, pipettes, flasks
    2.     Balance with precision of 0.001 g
    3.     Magnetic stirrer
    4.     Centrifuge
  1. Reagents
    1.     Ochratoxin A (OTA) analytical standard in powder form with a purity of > 99%
    2.     Pure toluene, methanol and ethanol (HPLC quality)
    3.     0.1-mol/L sodium acetate buffer with pH 5.2: dissolve 13.061 g sodium acetate trihydrate into 900 mL of distilled water. Adjust the pH to 5.2 with acetic acid then make up to 1000 mL with distilled water.
    4.     Preparation of ochratoxin A standard solutions:
      1.   50-mg/L stock solution in the toluene-acetic acid mixture: dissolve precisely 5 mg pure ochratoxin (3.4.1) in 100 mL toluene-acetic acid mixture (99:1, v/v). The stock solution may be kept at -20°C for up to a year.
      2.   20 mg/L Working solution in methanol: evaporate, using a nitrogen flow, an aliquot portion (20 mL) of stock solution, then re-dissolve in 50 mL pure methanol. The working solution may be kept at -20°C for up to 6 months.
      3.   Addition solutions of 10, 5 and 2 mg/L in ethanol: conduct successive dilutions of the working solution in absolute ethanol. The addition solutions may be kept at -20 °C for up to 2 months.
  2. Procedure

 

A summary of the conditions used for the preparation of control solutions and test solutions is provided in Table 2 (see below).

5.1.    Preparation of control solutions

Prepare each control solution from a sodium acetate buffer solution with a pH of 5.2 (3.4.3), adding 9 increasing concentrations of ochratoxin A to the control in order to obtain, for example, 50 mL of each supplemented control solution (see Table 1). Carry out the additions using the addition solutions (3.4.4.3). Conduct 2 repetitions per concentration. Ochratoxin A is then analysed in the 9 control solutions in order to obtain the initial concentrations measured.

 

5.2.    Preparation of test solutions

Place the 9 solutions supplemented with OTA (3.5.1) in contact with the selective plant fiber.

Procedure:

Add 0.05 g selective plant fibers to a small volume of acetate sodium buffer solution with a pH of 5.2 supplemented with OTA, then pour the mixture into a 25-mL calibrated flask and make up to 25 mL with this same buffer solution (the dose of plant fiber is 2 g/L). After 45 minutes of contact with the selective plant fibers while stirring, centrifuge the suspensions and separate the supernatant from the centrifugation pellet of fibers. Repeat this operation for the 9 control solutions supplemented with ochratoxin A (3.5.1). Ochratoxin A is then determined by HPLC, in order to obtain the residual concentrations measured in the supernatant. Conduct 2 repetitions per concentration.

 

Table 2: summary of the conditions for the determination of the capacity for adsorption of OTA

 

Contact time

45 minutes

Buffer used for testing

Sodium acetate (pH 5.2)

Selective plant fibres

Dose of 2 g/L (test solutions)

Absence (control solutions)

Concentration of ochratoxin A added

2 μg/L

5 μg/L

20 μg/L

125 μg/L

450 μg/L

900 μg/L

2,000 μg/L

5,000 μg/L

10,000 μg/L

Number of repetitions

2

Centrifugation – parameters

Room temperature

10000 rpm (round 13000 g) for 2-3 minutes

Method of analysis of ochratoxin A

Determination of ochratoxin A in wine after going through an immunoaffinity column (OIV-MA-AS315-10), followed by analysis by HPLC with fluorometric detection

 

  1. Calculations

 

The determination of the capacity for adsorption of ochratoxin A is calculated according to the following Freundlich equation:

where

  • KF = the selective plant fiber's capacity for adsorption of the molecule in µg/g of fiber,
  • n = the affinity of the selective plant fiber for the molecule,
  • CRes = the residual concentration of ochratoxin A measured in the test solution, in μg/mL, after contact with the selective plant fibers,
  • CAds = the concentration adsorbed by the selective plant fibers, in μg/g:
  • CAds in μg/g = CAds in μg /L / 2 (where the adsorbent dose = 2 g fibre/L buffer solution),
  • CAds in μg/L = the initial concentration measured in the control solution, in µg/L, before contact with the selective plant fibers CRes in μg/L.

Based on the residual concentrations (µg/L) measured, the concentrations of adsorbed ochratoxin A (μg/L) are thus calculated for each initial concentration and the regression curve Log CAds = 1/n Log CRes + Log KF is traced. The Freundlich adsorption regression of ochratoxin A by the selective plant fiber thus allows Freundlich's two constants to be calculated: the adsorption capacity in μg/g (KF) and the affinity of the fibre for ochratoxin A (n). The equation of the line y = ax + b gives the slope a =1/n and b = Log KF.

 

E.g. Freundlich isotherm for ochratoxin A

 

Freundlich isotherm for ochratoxin A

As such, in the below example, the following may be calculated:

  • b = Log KF = 3.0931, where  KF =10b = 1239.21
  • a = 1/n = 0.8307, where n = 1 /a = 1.2

The affinity (n) of the selective plant fiber for ochratoxin A is 1.2 and the adsorption capacity (KF) of ochratoxin A by the selective plant fiber is 1239.21 μg/g or mg/kg fiber.

Gelatine

COEI-1-GELATI Gelatine

Proteinum ossii

Gelatina

  1. Object, origin and field of application

 

Gelatine is the result of the partial hydrolysis of collagen contained in the skins, connective tissue and bones of animals. Gelatine comes in the form of roll sheets, flexible sheets, sprinkles, grains or colourless or slightly yellowish brown powder.

Certain gelatines are intentionally hydrolysed more than usual edible gelatines so as to be presented in ready-to-use colloidal solutions or in the form of atomised powder, soluble when cold. These products do not have the characteristic of becoming gel with water.

The structure and the iso-electric point of bovine skin gelatine proteins are different from gelatine from pork bones and rind.

Taking into account available scientific data, international standards and directives, gelatine must come from animals sources in compliance with recommendations from the International Office of Epizootics (IOE).

Gelatines are used as fining and clarification agents for wine. Gelatines react with wine tannins or additions and certain cations depending on their origin, the extraction process and their final degree of hydrolysis at the time of use in wine.

For the same quality of gelatine, the hydrolysis quality and the different phases of hydrolysis will produce products with very different behaviour concerning fining.

There is no single parameter to characterise the different types of gelatine due to their diversity.

  1. Labelling

The origin of basic edible gelatine must be indicated as well as the optimal storage conditions, expiration date and the concentration of SO2.

  1. Solubility

Basic edible gelatine swells in cold water. It dissolves in hot water (80°C to 90°C) and the solution jellifies upon cooling.

  1. Test trials

4.1.    Taste test

The solution in warm water should not have an unpleasant odour nor taste.

4.2.    pH

Evaluate the pH on a 1% solution at 40°C,

The colloidal solution pH level is between 3 to 4,

The solutions prepared from powder or grain products have a pH level between 5 to 7.

4.3.    Loss through dessication

4.3.1.  Solid form gelatine:

Place 2 g of gelatine in a 70 mm diameter silica capsule with a lid. Dry in an incubator at 100°C–105°C for 6 hours. Allow to cool in a covered capsule and a desiccator. Weigh. Let the quantity of dry residue be p g. Weight loss should not exceed 15%.

4.3.2.  Liquid form gelatine:

Put about 10 g of colloidal gelatine solution in a 70 mm diameter silica capsule. Weigh exactly this quantity in a covered capsule and dry over a water bath at 100°C for 4 hours. Then proceed by drying in an incubator at 100°C–105°C for 3 hours. Allow to cool in a covered capsule and a dessicator. Weigh the amount of dry residue. Given p g of this quantity. In relation to 100 g of the colloidal solution, the dry residue must reach a minimum of 5%.

All the limits set above are for the dry product.

4.4.    Ashes

Incinerate the dry residue from point 4.3 by slowly heating to 600°C in a muffle furnace after sprinkling gelatine with 0.2 to 0.3g of paraffin without ashes to avoid over spilling. Total ash content should not exceed 2.0%.

4.5.    Preparation of test trial solution

After being weighed, dissolve ashes in 2 ml of concentrated hydrochloric acid (R) and 10 ml of water. Heat to activate the dissolving and add distilled water until a volume equal to 25

times the weight of dried gelatine is reached. 1 ml of this solution contains mineral matter of 0.04 g of dried gelatine.

4.6.    Iron

Add 1 ml of concentrated hydrochloric acid (R), one drop of concentrate potassium permanganate at 1% (R), 2 ml of potassium thiocyanate at 5% (R) to 10 ml of the test trial solution (4.5).

If a red colouration appears, it must be lighter than the control sample prepared with 2 ml of iron solution (III) at 0.010 g per litre (R), 5.2 ml of water and the same amounts of concentrated hydrochloric acid (R) and potassium thiocyanate at 5% (R).

Iron content should be less than 50 mg/kg.

It is also possible to determine iron by atomic absorption spectrophotometry. (See method described in Chapter II of the International Oenological Codex).

4.7.    Chromium

Put 10 ml of test trial solution (4.5), 1 ml of ammonia persulfate solution at 15% (R), 0.5 ml of silver nitrate solution at 1% into a 50 ml conical flask. Heat and add potassium permanganate solution at 3% (R) drop by drop until the solution reaches a stable pink colour. Add a couple more drops and simmer 10 minutes. If the solution changes colour while boiling, add more potassium permanganate. After 10 minutes, add 1/10 diluted hydrochloric acid (R) until the solution is completely discoloured.

After cooling, transfer to a 20 ml graduated flask and add 2 ml of newly made 0.05% diphenylcarbazide solution in alcohol (R). Bring to 20 ml.

If a purplish red colouration appears, it must be lighter than the colour obtained when treating 4 ml of potassium dichromate solution at 0.001g of chrome per litre with 2 ml of sulphuric acid at 5% (R), 5 ml of distilled water, and after mixing add 2 ml of 0.05% diphenylcarbazide solution in alcohol (R) and bringing it up to 20 ml.

Chromium content should be less than 10 mg/kg.

It is also possible to determine chrome by atomic absorption spectrophotometry. (See method described in Chapter II of the International Oenological Codex).

4.8.    Copper

Put 2.5 ml of test trial solution (4.5) in a test tube and add 7.5 ml of water, 0.5 ml of hydrochloric citric solution (R), 1 ml 5M ammonia hydroxide (R), 0.5 ml of sodium diethyldthiocarbamate reagent (R). If a yellow colouration appears, it must not be darker than the solution obtained when adding the same volumes of the same reagents to 3.5 ml of a copper solution at 1 mg per litre (R) brought to 10 ml.

Copper content should be below 30 mg/kg.

It is also possible to determine copper by atomic absorption spectrophotometry (See method described in Chapter II of the International Oenological Codex).

4.9.    Zinc

Put 3.75 ml of distilled water, 5 ml of buffer acetate solution (R), 1 ml of sodium thiosulfate solution at 25% (m/v) (R), 5 ml of dithizone solution at 25 mg per litre in the dichloromethane (R) in 1.25 ml of test trial solution (4.5). Shake for 2 minutes. Separate the organic phase. The colouration must be lighter than the colour obtained when treating the same volumes of the same reagents, 2.5 ml of zinc solution at 1 mg per litre (R).

Zinc content should be less than 50 mg/kg.

It is also possible to determine zinc by atomic absorption spectrophotometry. (See method described in Chapter II of the International Oenological Codex).

4.10. Lead

Using the test trial solution (4.5), determine the lead according to the method in described in Chapter II of the International Oenological Codex by atomic absorption spectrophotometry.

Lead content should be less than 5 mg/kg.

4.11. Mercury

Determine the mercury according to the method described in Chapter II of the International Oenological Codex by atomic absorption spectrophotometry.

Mercury content should be less than 0.15 mg/kg.

4.12. Arsenic

Determine the arsenic according to the method in Chapter II of the International Oenological Codex by atomic absorption spectrophotometry.

Arsenic content should be less than 1 mg/kg.

4.13. Cadmium

Determine the cadmium according to the method described in Chapter II of the International Oenological Codex by atomic absorption spectrophotometry.

Cadmium content should be less than 0.5 mg/kg.

4.14. Determining total nitrogen

Determine the total nitrogen according to the method in Chapter II of the International Oenological Codex. Total nitrogen must be more than 14% of the weight of dry gelatine.

4.15. Sulphur dioxide

Gelatine in dried form

Sulphur dioxide, freed by a little excess of phosphoric acid, starts to boil under the reflux of a flow of nitrogen. Which is oxidised and set by a hydrogen peroxide solution and measured by an acid meter in the presence of bromophenol blue, according to the reference method in the Compendium of International Methods of Analysis of Wines and Musts. This is done with a sample of 2 g of solid gelatine and on 10 ml of diluted solution at 10% of gelatine.

Sulphur dioxide content should not exceed 50 mg/kg.

Gelatine in colloidal solution form

Liquid forms are stabilised with SO2 and should not contain benzylic alcohol; sulphur dioxide content should not exceed 4 g/litre.

4.16. Urea

Determine urea using the Boehringer enzymatic method.

Content should be less than 2.5 g/kg.

4.17. Bacteria monitoring

Proceed as is indicated in Chapter II of the International Oenological Codex.

Limit: total viable micro-organisms: less than 104 CFU/g

4.18. Escherichia coli

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Absence checked on a sample of 1 g.

4.19. Salmonella

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Absence of salmonella is checked on a 25 g sample.

4.20. Coliforms

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Absence of coliform bacteria is checked on a 1 g sample.

4.21. Spores of anaerobic sulphite-reducing micro-organisms[1]

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Absence is checked on a 1 g sample.

4.22. Clostridium perfringen spores[2]

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Absence is checked on a 1 g sample.

4.23. Staphylococci (Staphylococcus aureus)

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Absence is checked on a 1 g sample.

4.24. Yeasts

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Content limit: 103 CFU/g of preparation.

4.25. Total lactic bacteria

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Content limit: 103 CFU/ g of preparation.

4.26. Acetic bacteria

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Content limit: 103 CFU/ g of preparation.

4.27. Mould

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Content limit: 103 CFU/g of preparation.

  1. Storage

Solid gelatine must be stored in closed containers or in a humidity-proof bag under temperate conditions.

Gelatine in ready-to-use colloidal solutions may contain preservatives authorised in wines and their concentrations must be indicated on the label.


[1] Method to be defined later on by the experts’ group “Wine microbiology”.

[2] Method to be defined later on by the experts’ group “Wine microbiology”.

Glutathione

COEI-1-GLUTAT Glutathione

Chemical name: γ-L-Glutamyl-L-cysteinyl-glycine

CAS number: 70-18-8

Molecular weight: 307.33 g/mol

Glutathion.svg

  1. Object, origin and scope of application

Reduced glutathione (GSH) is a biologically active tripeptide consisting of L-glutamate, L-cysteine and glycine. Its antioxidant properties can fight against oxidation phenomena in musts and wines and protect aromatic compounds.

GSH is principally produced by microbial fermentation. The more onerous methods of production – chemically or by enzymatic reaction – are not used on an industrial scale.

Production by microbial fermentation frequently uses Saccharomyces cerevisiae and Candida utilis or other non-Saccharomyces microorganisms, and more generally their mutant forms. The GSH content in cultures of mutant yeast strains is usually high (3.5%-9% of dry cell weight).

When mutants used for GSH production come from genetically modified yeasts, they must be authorised for use beforehand by the relevant authorities.

  1. Labelling

The label must indicate:

  • the name or sales denomination,
  • the indication ‘product for oenological use, limited use’,
  • the GSH content,
  • any additives,
  • instructions for use,
  • the batch number as well as the expiry date, and the storage conditions in terms of temperature, humidity and ventilation conditions,
  • the name of the genus and the species of microbial sources (only if produced by microbial fermentation),
  • the indication that the GSH was produced by mutants obtained by genetic modification and the modified characteristic if such is the case (only if produced by microbial fermentation),
  • the name or company name and address of the manufacturer, packager or supplier,
  • the net weight
  1. Characteristics

GSH is usually available in white crystalline powder form soluble in water, which results in a clear and colourless aqueous solution with a light flavour of reduction. Precautions must be taken (points 4.3. and 6) to ensure the stability of GSH in order to avoid oxidation and oxidised glutathione (GSSG) production.

3.1.    Identification

3.1.1.  Rotatory power

Specific rotatory power:

Melting point

  • 190-195 °C
  1. Limits and test methods

4.1.    GSH content

Reduced glutathione (GSH) concentrations are measured by the capillary electrophoresis method described in the Annex.

The reduced glutathione content must be ≥ 98%.

4.2.    Humidity

Measured by the loss in the weight of 5 g of product, dried at 105 °C until the weight is constant (for approximately 3 hours). The maximum humidity of the solid form must be less than or equal to 0.5%.

4.3.    Test solution

Dissolve 1 g of GSH in 100 mL of type-I ultra-pure water (UPW). The GSH solution must be prepared each day and stored at low temperature (2-4 °C) in a brown glass bottle.

4.4.    Lead

Proceed with determination according to the method indicated in Chapter II of the International Oenological Codex.
The lead content must be less than 2 mg/kg of dry matter.

4.5.    Mercury

Proceed with determination according to the method indicated in Chapter II of the International Oenological Codex. The mercury content must be less than 1 mg/kg of dry matter.

4.6.    Arsenic

Proceed with determination according to the method indicated in Chapter II of the International Oenological Codex. The arsenic content must be less than 3 mg/kg of dry matter.

4.7.    Cadmium

Proceed with determination according to the method indicated in Chapter II of the International Oenological Codex. The cadmium content must be less than 1 mg/kg of dry matter.

4.8.    Living yeasts

Enumerate according to the method indicated in Chapter II of the International Oenological Codex. The live yeast count must be less than or equal to 102 CFU/g.

4.9.    Moulds

Enumerate according to the method indicated in Chapter II of the International Oenological Codex. The mould count must be less than 102 CFU/g.

4.10. Lactic acid bacteria

Enumerate according to the method indicated in Chapter II of the International Oenological Codex. The lactic bacteria count must be less than 103 CFU/g.

4.11. Acetic acid bacteria

Enumerate according to the method indicated in Chapter II of the International Oenological Codex.
The acetic acid bacteria count must be less than 103 CFU/g.

4.12. Salmonella

Enumerate according to the method indicated in Chapter II of the International Oenological Codex. Absence must be checked on a sample of 25 g.

4.13. Escherichia coli

Enumerate according to the method indicated in Chapter II of the International Oenological Codex.
Absence must be checked on a sample of 1 g.

4.14. Staphylococci

Enumerate according to the method indicated in Chapter II of the International Oenological Codex. Absence must be checked on a sample of 1 g.

4.15. Coliforms

Enumerate according to the method indicated in Chapter II of the International Oenological Codex.
The coliform count must be less than 10 CFU/g.

  1. Additives

They must comply with the currently applicable regulations.

  1. Storage

Store in sealed packaging in a cool (2-8 °C), dry place. In all cases, refer to the manufacturer's instructions.

Annex: Determination of glutathione (GSH) in commercial preparations by capillary electrophoresis

This determination is carried out according to the method for the determination of glutathione in musts and wines (Resolution OIV-OENO 345-2009).

The glutathione samples to be determined are prepared by dilution of the test solution (point 4.3 of the glutathione monograph) so as to obtain a final concentration of around 20 mg/L (e.g. 200 μL in 100 mL of ultra-pure water if the level of glutathione in the commercial preparation is close to 100%). If necessary, this preparation should be clarified by centrifugation before being analysed.

  1. Method characteristics

Certain internal elements of validation were determined in the wine matrix (Resolution OIV-OENO 345-2009) to produce calibration curves and repeatability tests. Each concentration is calculated based on the average of three determinations obtained by using the regression line of the calibration curve. The results are expressed in mg/L. The linear regression and correlation coefficient are calculated according to the least squares method. The glutathione stock solution is produced from an HCl/EDTA solution, allowing it to be stored at +6 °C for several days with no loss. Successive dilutions of this solution allow the threshold limit of detection of the method to be estimated, for a signal-to-noise ratio of three of more.

The calibration curve is established between 0 and 40 mg/L, the linear regression equates to Y = 0.583X – 0.948 and the correlation coefficient is 0.9966.

These analytical conditions make it possible to eliminate interference caused by MBB hydrolysis products.

The method’s repeatability is calculated on the basis of 10 analyses of the same sample of wine. For a 10 mg/L concentration, the coefficient of variation is 6.0% for glutathione.

The limit of detection of glutathione is 20 μg/L (in the wine) and the limit of quantification is 60 μg/L.

  1. Bibliography
  • See Resolution OIV/OENO 345/2009.

Gum arabic

COEI-1-GOMARA Gum arabic

Gumme arabicum

Acaciae gummi

SIN No.414

  1. Objective, origin and scope of application

Gum arabic is a gummy exudation which hardens in air and flows naturally or through cuts made in tree trunks and branches of the L. Acacia senegal L. Willdenow and other African Acacia species.  It is composed of spherical tear drop-shaped globules, or sometimes irregular oval shapes with a diameter of 1-3 cm.

Gum arabic exists in powder form or in colloidal solution.

The product is used to improve the stability of bottled wine.

Gum arabic is composed of a polysaccharide rich in galactose and arabinose along with a small protein fraction which gives its stabilizing power with respect to the precipitation of coloring substances and iron or copper breakdown.

There are limits imposed on the quantity of gum arabic used in wine.

  1. Labelling

The label should indicate the gum arabic solution concentration and sulfur dioxide content (there are limits imposed on the sulfur dioxide content in wine), as well as its safety and storage conditions.

  1. Properties

 

Gum arabic tear drops are relatively friable and break cleanly into fragments.  Whole tear drops often have a small cavity in the center.

Powdered gum arabic is odorless, tasteless, and has a white or yellow transparent color and glassy luster. It dissolves slowly in twice its weight and leaves only a slight residue of vegetable debris. It is insoluble in alcohol.

Gum arabic in solution is a yellowish-white viscous, translucent liquid which is slightly acidic.  It precipitates abundantly when an equal volume of ethanol is added.

  1. Tests

4.1.         Desiccation loss

4.1.1.  Powdered gum arabic

Place 5 g of gum arabic in a silica dish with a diameter of 70 mm.  Place in a n oven at 100-105 °C for 5 hours.  Weight loss should be no greater than 15 pp 100.

4.1.2.  Gum arabic in solution

Place 10 g of gum arabic solution in a silica dish with a diameter of 70 mm.  Place in a water bath at 100 °C for 4 hours, then in an oven set to 100-105o C for 3 hours.  The quantity of dry residue should be at least 10 pp 100.

The limiting values indicated below are for dry product.

4.2.         Ash

Incinerate the dry residue at 550-600 °C.  Ash content should not be greater than 4 pp 100.

4.3.         Preparing the Solution for Tests

The ash from 5 g of powdered gum arabic or from a weight of solution corresponding to 5 g of solid gum arabic are taken up by 2 ml of concentrated hydrochloric acid (R).  Place in a 100 °C water bath with a stirring apparatus to ensure solubilizing.  Decant in a 50 ml volumetric flask and bring the volume to 50 ml using wash water from the dish used during incineration.

4.4.         Iron

Add 1 drop of 1 pp 100 potassium permanganate (R), 1 ml of concentrated hydrochloric acid (R) and 2 ml 2 ml of 5 pp 100 potassium thiocyanate to 10 ml of the solution prepared for tests under paragraph 4.3.  The resulting coloration should be less intense than that of a control prepared with 6 ml of an iron (III) solution with 10 mg of iron per liter (R), 4 ml of water, 1 ml of concentrated hydrochloric acid (R) and 2 ml of 5 pp 100 potassium thiocyanate (R). (Iron content should be less than 60 mg/kg).

Iron content can also be quantified by atomic absorption spectometry using the technique explained in the Compendium.

4.5.         Cadmium

Using the techniques described in the annex, determine the cadmium content in the test solution prepared in accordance with Par. 4.3. (Content should be less than 1 mg/kg.)

4.6.         Lead

Using the techniques described in the Compendium, determine the lead content in the test solution prepared in accordance with Par. 4.3. (Content should be less than 5 mg/kg.)

4.7.         Mercury

Using the techniques described in the annex, determine the mercury content in the test solution prepared in accordance with Par. 4.3. (Content should be less than 1 mg/kg.)

4.8.         Arsenic

Mineralize 0.5 g of dry gum arabic using the nitrosulfuric method and test for arsenic using the method described in the Annex. (Arsenic content should be less than 3 mg/kg).

4.9.         Total nitrogen

Place 5 g of gum arabic in a 300 ml mineralization cucurbit with 15 ml of concentrated sulfuric acid (R) and 2 g of mineralization catalyst.  Proceed with the quantitative analysis as indicated in the annex.

For gum arabic in solution, weigh an amount corresponding to 5 g dry residue.  Evaporate until almost dry, then proceed as described before.

(Nitrogen content should be less than 4 g/kg).

Nitrogen content should be between:

  • 0.25% and 0.4% (m/m) for Senegal Acacia gum and
  • 0.10% and 0.20% (m/m) for Seyal Acacia gum.

4.10.     Starch and Dextrin

Bring 20 ml of solution containing 2 g of dry gum arabic to a boil.  Cool.  Add 0.2 ml of 0.05M iodine.  No blue or red-brown coloration should appear.

 

4.11.     Tannin

Add 0.1 ml of iron (III) sulfate (R) to 10 ml of solution containing 1 g of dry gum arabic.  A gelatinous precipitate will form, but neither the precipitate nor the liquid should become dark blue.

4.12.     Rotatory power

Specific rotatory power is measured at 589 nm (sodium line) and for a solution with 1 g/ml of gum and a length of 1 dm.

 

 

4.13.     Salmonella

A 1 g sample must be free from salmonellosis (determination procedure described in the annex).

4.14.     Escherichia coli

A 1 g sample must be free from Escherichia coli (determination procedure described in the annex).

4.15.     Hydrolytic Products

Mannose, xylose, and glacturonic acid should not be present (as determined by chromatography).

4.16.     Efficacy Test for Gum Arabic

4.16.1.                      Principle

Determine the quantity of gum arabic required to prevent flocculation of a colloidal iron (III) hexacyanoferrate (II) solution in an aqueous-alcoholic medium by calcium salt.

4.16.2.                      Products

  • Crystallized tartaric acid: Molar weight = 150.05
  • Purified potassium sulfate (K2SO4): Molar weight = 174.25
  • Dihydrous calcium chloride (CaCl2,2H2O): Molar weight = 143.03
  • Crystallized iron (III) chloride (FeCl3,6H2O): Molecular weight = 270.32
  • Potassium hexacyanoferrate (II) (K4[Fe(CN)6]): Molecular weight = 422.4
  • Metatartaric acid
  • 1M sodium hydroxide solution
  • Ethanol, 95% by volume
  • 20 volumes hydrogen peroxide solution
    1.                       Protocol

Gum arabic solution in a concentration of 5 g/l (A)

Dissolve 5 g of gum arabic in 100 ml of distilled water, then dilute this solution to 1/10 strength using distilled water.

Iron (III) solution in a concentration of 2.5 g iron/l (B)

Weigh exactly 1.21 g of iron (III) chloride and place it in a 100 ml volumetric flask. Fill to 3/4 with distilled water and add 0.1 ml of hydrogen peroxide solution at 20 volumes.  Adjust to the flask mark with distilled water.

 

Calcium chloride solution in a concentration of  27 g/l (C)

Dissolve exactly 2.7 g of dihydrous calcium chloride in 100 ml of distilled water.

 

Hydro-alcoholic Matrix (D)

Fill a 1 liter volumetric flask half way with distilled water, then dissolve the following in order:

Tartaric acid: 2.5 g

K2SO4: 1 g (complete dissolution before proceeding to the following)

Metatartaric acid: 50 mg

Ethanol, 95% by volume: 120 ml

1M NaOH: 10 ml

Adjust the pH of the matrix to 3.5 by adding 1M NaOH (1-2 ml).  Homogenize and top off with distilled water.

Potassium hexacyanoferrate (II) solution in a concentration of 12.5 g/l (E)

Weigh exactly 0.25 g of potassium hexacyanoferrate and place it in a 20 ml volumetric flask.  Top off with distilled water.

This preparation should be made extemporaneously.

4.16.4.                      Test

Place the liter of matrix (D) in a flask and add exactly 2 ml of potassium hexacyanoferrate (II) solution (E).  Place a stopper in the flask and shake.  Next, add 1 ml of iron (III) chloride solution (B).  Shake and let sit one-half hour.  Solution S (blue in color).

In a series of test tubes (capacity > 50 ml), pour increasing volumes of gum solution in concentrations of 5 g/l (A): 0 - 0.25 - 0.5 - 0.75 - 1.0 - 1.25 - 1.5 - 1.75 - 2.0 - 2.5 - 3.0 ml.

These volumes correspond to final gum concentrations of 0 - 25 - 50 - 75 - 100 - 125 - 150 - 175 - 200 - 250 and 300 mg/l.

Place 50 ml of solution S to each test tube.  Shake and let sit 5 minutes.

Next, pour 1 ml of calcium chloride solution (C) into each tube.  Place a stopper in the tube and agitate.

Store the tubes at ambient temperature ( 25 °C) and out of the light.

After 3 days, read:

The control tube should have a deep blue deposit with a nearly colorless surfactant.  This deposit will be more or less significant in the other tubes depending on the efficacy and dose of gum added.

In one tube, a solution with a homogeneous color and no blue deposit at the bottom will be seen.  This corresponds to the quantity in mg/l of efficacious gum arabic to use in the wine.

  1. Storage

Solid gum arabic has a very long shelf life if stored in a dry, temperate place in sealed packages.  Solutions have a limited shelf life due to the presence of sulfur dioxide.

Kaolin

COEI-1-KAOLIN Kaolin

Kaolinum

  1. Objective, Origin and Scope of Application

Kaolin is a natural hydrated aluminum silicate.

It is used as a clarification agent in wines.

  1. Labelling

The label should indicate purity and safety and storage conditions.

  1. Properties

Fine white or yellowish-white powder which is oily to the touch. When weakened in hot water it releases a clay-like odor. It is insoluble in water and dilute acids.

The product of the alkaline liquefaction of kaolin taken up by water exhibits the reaction properties of alkaline aluminates and alkaline silicates.

  1. Tests

4.1.         Consistency

Mix 1 g of kaolin with 1ml of water.  The resulting paste should not be runny.

4.2.         Water Loss at 700 °C

Burn a precisely-weighed sample of about 1 g of kaolin at 700 °C.  Weight loss should not be greater than 15 pp 100.

4.3.         Products Soluble in Dilute Acids

Weaken 1 g of kaolin in 50 ml of 0.2M hydrochloric acid.  Bring to a boil under reflux for 15 minutes.  Filter. The filtrate, when evaporated then incinerated, should not leave a residue of more than 2 pp 100.

4.4.         Preparing the Solution for Tests

Macerate 5 g of kaolin with 100 ml of citric acid in a concentration of 5 g per liter with a pH of 3.5 for 24 hours, stirring from time to time.  Filter.

4.5.         Soluble Iron

Add 1 ml of concentrated hydrochloric acid (R) and 5 ml of 5 pp 100 potassium thiocyanate to 10 ml of the solution prepared for tests under paragraph 4.4.  The resulting coloration should be less intense than that

of a control prepared with 5 ml of an iron solution in a concentration of 0.010 g of iron per liter (R), 5 ml of citric acid in a concentration of 20 g per liter (R), 1 ml of concentrated hydrochloric acid (R) and 5 ml of 5 pp 100 potassium thiocyanate (R).  (Soluble iron content should be less than 100 mg/kg).

It is also possible to determine iron content using the atomic absorption photometry method described in the Compendium.

4.6.         Calcium

To 5 ml of the solution prepared for tests under paragraph 4.4, add 5 ml of ammonium oxalate in a 4 pp 100 solution (R), 5 drops of bromophenol blue (R) and a sufficient quantity of concentrated ammonium hydroxide (R) to turn the indicator blue.  There should be no clouding.

4.7.         Soluble Magnesium and Aluminum

To 5 ml of the solution prepared for tests under paragraph 4.4, add 5 ml of 10 pp 100 sodium phosphate solution (R), 1 drop of phenolphthalein in a concentration of 1 g per 100 ml alcohol at 90% by volume (R) and a sufficient quantity of diluted ammonium hydroxide (R) to obtain a pink coloration.  No precipitate should form in less than one hour.

4.8.         Lead

Using the technique described in the Compendium, determine the lead content in the test solution prepared in accordance with Par. 4.4. (Lead content should be less than 5 mg/kg.)

4.9.         Mercury

Using the technique described in the annex, determine the mercury content in the test solution prepared in accordance with Par. 4.4. (Content should be less than 1 mg/kg.)

4.10.     Arsenic

Using the technique described in the annex, determine the mercury content in the test solution prepared in accordance with Par. 4.4. (Content should be less than 3 mg/kg.)

4.11.     Evaluation of Coarse Particles

Place a suspension of 5 g of kaolin in 60 ml of a 1 pp 100 tetrasodic pyrophosphate solution (R) in a 250 ml test tube (diameter of approximately 40 mm) with an emery stopper.  Shake vigorously for 1-2 minutes.  Let sit for 5 minutes then use a siphon to draw off 50 ml of the suspension.  The siphon should have two tubes whose length ratio is 2:5. It should consist of a glass tube with a diameter of 5 mm.  The tip of the small tube, which should be suitably tapered, is then placed and maintained below the surface of the liquid so the siphon is drained once 50 ml of the suspension have been drawn.

Add 50 ml of water to the remaining liquid. Stir and let sit 5 minutes, then take another 50 ml sample with the siphon.  Repeat this procedure until 400 ml of water have been taken up.  Finally, decant the residue remaining in the test tube into a calibrated crucible.

Dry evaporate, then dry at 100 °C for 15 minutes.  Weigh.  The residue should not be greater than 2 pp 100.

4.12.     Adsorption Power

Place 1 g kaolin and 10 ml 0.01M methylene blue in a test tube with a stopper and let the deposit form.  Centrifuge the solution and dilute 100 times. The solution should be no more intensely colored than a 0.08 mM methylene blue solution.

  1. Storage

Kaolin should be stored in well-ventilated, places at moderate temperatures in airtight containers and away from volatile substances it can adsorb.

Skim milk

COEI-1-LAIECR Skim milk

  1. Object, ORIGIN and field of APPLICATION

Skimmed cow’s milk can be used to clarify wine. Its coagulation traps particles which are eliminated in the sediments. It must not introduce a taint into the wine.

The use of skimmed cow’s milk may give rise to possible residual proteins in wine which may provoke a possible allergic reaction for some individuals.

Its use must comply with regulations in force for skim milk.

  1. Composition AND limits

Skim milk must comply with regulations in force concerning foodstuffs intended for human consumption.

Saccharomyces SPP. selected yeasts

COEI-1-SACCHA Saccharomyces spp. Selected yeasts

  1. Object, origin and field of application

 

Saccharomyces spp. selected yeasts can be used for the inoculation of grapes, musts and wine according to resolution OENO-MICRO 14-546 in order to initiate and/or ensure completion of alcoholic fermentation and the production of special wines.

Yeasts used must be isolated from grapes, musts or wine or result from hybridisation of grape/must/wine strains, or have been derived from other wine yeasts. Prior to the use of genetically modified oenological yeasts, authorisation by competent authorities is required.

  1. Labelling

The following information must be indicated on the packaging:

  • the genus name (Saccharomyces), the species name, the name of the strain(s) and all elements that can guarantee the traceability of the product,
  • the physical form of the products as described in point 3,
  • the name of the selector,
  • the name and contact address of the manufacturer or marketer or distributor,
  • operating instructions recommended by the manufacturer,
  • a recommended rate of inoculation,
  • the minimum number of viable cells per gram of product (CFU as determined in 4.6) guaranteed by the manufacturer, with a recommended storage temperature,
  • the manufacturing batch number, the expiration date and storage conditions,
  • where relevant, the indication that the yeast strain(s) were obtained through genetic modifications and their modified character(s),
  • all additives present.
  1. Characteristics

 

The formulation is a pure culture or a blend of strains of Saccharomyces or a blend of Saccharomyces and non-Saccharomyces.

Saccharomyces selected yeasts can be used in the following forms:

  • Active Dry Yeast (ADY) with a minimum dry matter of 92% and a level of viable yeasts equal or above to 1010 CFU/g of dry matter,
  • Active Frozen Yeast (AFY) with a range of dry matter from 40 to 85% and a level of viable yeasts equal to or above 1010 CFU/g of dry matter,
  • Compressed Yeast (COY) with a range of dry matter from 30 to 35% and a level of viable yeasts equal to or above 1010 CFU/g of dry matter,
  • Cream Yeast (CRY) with a range of dry matter from 18 to 25% and a level of viable yeasts equal to or above 1010 CFU/g of dry matter,
  • Encapsulated (beads) or Immobilised Yeasts (ENY) with alginate and/or other products admitted by the OIV, with a minimum of dry matter of 86% and a level of viable yeasts equal to or above 109 CFU/g of dry matter,
  • “levain de tirage” for sparkling wines containing above 50x106 of viable cells per mL.
  1. Limits and methods of analysis

4.1.    Humidity

Measured bythe weight loss of 5 g of product dried at 105 °C until it reaches a constant weight. Content should satisfy the characteristics of humidity or water level described in point 3.

4.2.    Lead

Proceed with the determination according to the method in Chapter II of the International Oenological Codex.

Content should be less than 2 mg/kg of the suitable preparation described in point 3.

4.3.    Mercury

Proceed with the determination according to the method in Chapter II of the International Oenological Codex.

Content should be less than 1 mg/kg of the suitable preparation described in point 3.

4.4.    Arsenic

Proceed with the determination according to the method in Chapter II of the International Oenological Codex.

Content should be less than 3 mg/kg of the suitable preparation described in point 3.

 

4.5.    Cadmium

Proceed with the determination according to the method in Chapter II of the International Oenological Codex.

Content should be less than 1 mg/kg of the suitable preparation described in point 3.

4.6.    Total viable yeasts

Proceed with counting according to the method in Chapter II of the International Oenological Codex. Content should comply with the characteristics described in point 3.

4.7.    Yeasts other than those indicated on the label

Proceed with counting according to the method in Chapter II of the International Oenological Codex, in order to obtain colonies for further identification.

4.7a. Determination of a contaminant based on the genus: a contaminant population of a different genus to Saccharomyces should be 5 logs less than the total population of strains indicated on the label, and defined in the characteristics described in point 3. Proceed with counting according to the method described in Chapter II of the International Oenological Codex to distinguish between Saccharomyces and non-Saccharomyces.

4.7b. Determination of a contaminant based on the species or strain: the species and strains indicated on the packaging should account for at least 95% of the total yeast population. Proceed with control according to Annex 1.

4.8.    Moulds

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Content should be less than 103 CFU/g of the suitable preparation described in point 3.

4.9.    Lactic acid bacteria

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Content should be less than 105 CFU/g of the suitable preparation described in point 3.

4.10. Acetic acid bacteria

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Content should be less than 104 CFU/g of the suitable preparation described in point 3.

4.11. Salmonella

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Absence should be checked on a 25 g sample.

 

4.12. Escherichia coli

Proceed with counting according to the method in Chapter II of the International Oenological Codex using the selective differential medium for Escherichia coli.

Absence should be checked on a 1 g sample.

4.13. Staphylococci

Proceed with counting according to the method in Chapter II of the International Oenological Codex. The presence of staphylococci is evaluated by an enrichment culture in a liquid Giolitti and Cantoni medium followed by a confirmation on a solid Baird Parker medium.

In the case that the Giolitti and Cantoni medium gives positive results, the presence of Staphylococci is confirmed by isolation on a solid Baird Parker medium. A positive culture medium loop is used to inoculate solid BP mediums to obtain isolated colonies.

Absence should be checked on a 1 g sample.

 

4.14. Coliforms

Proceed with counting according to the method in Chapter II of the International Oenological Codex using a selective differential medium for coliforms, desoxycholate gelose.

Number should be less than 102 CFU/g of the suitable preparation described in point 3.

 

  1. Additivies

 

These must be conform with regulations in force.

  1. Storage conditions

Products must be stored and propagated under conditions which favour their genetic stability.

Refer to manufacturer’s recommendations.

  1. Product documentation

Product documentation should specify guidelines about storage, transportation, handling and application conditions (temperature, activation, rehydration when needed, possibly in suitable must or wine suspensions, etc.).

Annex 1

  1. Obtention of colonies

 

Sample 1 g or 1 mL in case of “levain de tirage” , and suspend it under sterile conditions in 100mL sterile saccharose 5%. Homogenise and allow standing at 25-30 °C for 20min.

After adequate serial decimal dilutions, spread 0.1mL of the diluted sample onto the surface of a nutrient YEPD agar plate (Glucose 20 g, Peptone 20 g, Yeast extract 10 g, 100 mg chloramphenicol to avoid bacterial growth and 150mg biphenyl to avoid mould growth, Agar-agar 20 g, Water q.s.p. 1000 mL). Incubate for 6 days at 25 °C in aerobiosis. All yeast can grow even non-Saccharomyces that would contaminate or be part of the blend with Saccharomyces spp. in the preparation.

  1. Identification of contaminant species/strains

 

Identification is carried out on the colonies isolated on plates. 

As indicated in the characteristics, the contaminant population (which is neither the pure strain nor the different strains in case of mixed strains)

should be less than 5% of the total population. After the dilutions needed to obtain individual colonies, if 20 colonies out of 300 are identified,  a contaminant at 5% (ideally) should represent 1 colony out of 20.

The contaminant is identified based on the species by D1/D2 sequencing (see 2.1).

If all of the colonies are of the same species, it is possible to verify that a contaminant strain corresponds to less than 5% through analysis of 20 colonies, using SSR or delta PCR for the species S. cerevisiae (see 2.2).

If the preparation is a blend of 2 or 3 species/strains, the least represented is 15% of the total. The verification of the composition of the mix by identification of colonies is not appropriate. Indeed, for 2 strains in the blend, the less represented should produce 3 colonies out of 20 identified, picked up out of 400 on the plate.

Therefore it can be suggested that the checking for 2 or even more species in blend (proportion of the different species), use the quantitative specific PCR with probes targeting each of the expected species. In this case there is no preliminary plate culture. DNA is extracted directly from the sample. 

For controlling blends of same species strains (proportion of the different strains) the only possibility up to date cannot exclude the plate culture is and identification of colonies to the strain level; the result needs to be interpreted with precaution since the representation of each strain on the plates is affected, by the growth ability on the one hand and on the other by the excessively low number of colonies that can reasonably be identified.

2.1.    Identification of the species

The species is identified by DNA sequencing of the variable domain D1/D2 of 26S ribosomal region obtained by PCR amplification. It is the “method of choice” for yeast species identification: strains with more than a 1% sequence divergence of the domain D1/D2 of 600 nucleotides are not of the same species.

Suspend separately, colonies directly in the PCR mixture, or previously in water (about 50 μL depending on the size of the colony) and add a sample to the PCR mixture;

PCR mixture (final volume 50 μL): 10 mM Tris HCl pH 8, 50 mM KCl, 0.1% Triton X100 v/v, 0.2 mg/mL BSA, 3.12% v/v glycerol, 1.5 mM MgCl2, 200 μM dNTPs, 0.1 U/ μL Taq polymerase;

primers: NL1/NL4. NL 1 (5'-GCATATCAATAA GCGGAGGAAAAG) and NL 4 (5'-GGTCCGTGTTTCAA GACGG);

amplification is performed, after 10 min at 95 °C to make accessible DNA, by 30 cycles comprising the steps, 95 °C for 1 min, 55 °C for 45 s, 72 °C for 1 min, then a final step at 72 °C for 7 min;

PCR product is purified by any “PCR purification kit” and sequenced using the primers used for the amplification;

obtained sequences are compared to those available in the Genebank database (www.ncbi.nih.gov./Genbank).

2.2.    Identification of strains

When the species is identified, it is possible to identify the strains. For most wine yeast species, at least the main ones used as starters, the most reliable and accurate method for identification is based on the analysis of sequence repeats (microsatellites or SSR) . Strains differ by the number of repetitions of short sequences at certain point of their genome. These loci are delimited by conserved regions that are chosen as primers for PCR amplification. The analysis consists in PCR amplification of several loci, with suitable primers for each yeast species, and measurement of their length by capillary electrophoresis for sequencing (with a degree of resolution of a single nucleotide).

Note:

  • at the time of writing, strain typing is not possible for all yeast species;
  • in order to further the advances in knowledge, suitable primers for each yeast species are chosen by referring to studies published in international peer-review scientific journals;
  • for some species about 9-12 loci are analysed; some loci are more discriminant than others;
  • the analysis can be simplified by considering first a smaller number of loci chosen for their better discriminating power, and continuing the analysis in case of ambiguity;
  • amplification can be done in multiplex (up to 9 primer pairs) for some species like S. cerevisiae which shorten and simplify the analysis.

For Saccharomyces cerevisiae, the “inter-delta PCR” profile (cf OIV-OENO 408-2011) can be used. However in case of ambiguity, when the profiles appear different but are still very close, typing by SSR is required.

Non saccharomyces SPP. selected yeasts

COEI-1-NOSACC Non-Saccharomyces selected yeasts

  1. Object, origin and field of application

Non-Saccharomyces yeasts can be used for the inoculation of grapes, musts and wine according to resolution OENO-MICRO 14-546. As addition of non-Saccharomyces yeast might not result in the completion of alcoholic fermentation, inoculation with non-Saccharomyces may be followed by or carried out at the same time as inoculation with Saccharomyces spp.

Yeasts with desirable oenological properties must be isolated from grapes, musts or wine or result from hybridisation of grape/must/wine strains, or have been derived from other wine yeasts.

Prior to the use of genetically modified oenological yeasts authorisation by competent authorities is required.

  1. Labelling

The following information must be indicated on the packaging :

  • the genus name, the species name, the name of the strain(s) and all elements that can guarantee the traceability of the product,
  • the physical form of the products as described in point 3,
  • the name of the selector,
  • the name and contact address of the manufacturer or marketer or distributor,
  • operating instructions recommended by the manufacturer,
  • a recommended rate of inoculation,
  • the minimum number of viable cells per gram of product (CFU as determined in 4.6) guaranteed by the manufacturer, with a recommended storage temperature,
  • the manufacturing batch number, the expiration date and storage conditions,
  • where relevant, the indication that the yeast strain(s) were obtained through genetic modifications and their modified character(s),
  • all additives present.
  1. Characteristics

The formulation is a pure culture or a blend of non-Saccharomyces strains, or a blend of strains of Saccharomyces and non-Saccharomyces.

Non-Saccharomyces selected yeasts can be used in the following forms:

  • Active Dry Yeast (ADY) with a minimum dry matter of 92% and a level of viable yeasts equal or above to 1010 CFU/g of dry matter,
  • Active Frozen Yeast (AFY) with a range of dry matter from 40 to 85% and a level of viable yeasts equal to or above 1010 CFU/g of dry matter,
  • Compressed Yeast (COY) with a range of dry matter from 30 to 35% and a level of viable yeasts equal to or above 1010 CFU/g of dry matter,
  • Cream Yeast (CRY) with a range of dry matter from 18 to 25% and a level of viable yeasts equal to or above 1010 CFU/g of dry matter,
  • Encapsulated (beads) or Immobilised Yeasts (ENY) with alginate and/or other products admitted by the OIV, with a minimum of dry matter of 86% and a level of viable yeasts equal to or above 109 CFU/g of dry matter,
  1. Limits and methods of analysis

4.1.    Humidity

Measured by the weight loss of 5 g of product dried at 105 °C until it reaches a constant weight

Content should comply with the characteristics of humidity or water level described in point 3.

4.2.    Lead

Proceed with the determination according to the method in Chapter II of the International Oenological Codex.

Content should be less than 2 mg/kg of the suitable preparation described in point 3.

4.3.    Mercury

Proceed with the determination according to the method in Chapter II of the International Oenological Codex.

Content should be less than 1 mg/kg of the suitable preparation described in point 3.

4.4.    Arsenic

Proceed with the determination according to the method in Chapter II of the International Oenological Codex.

Content should be less than 3 mg/kg of the suitable preparation described in  point 3.

4.5.    Cadmium

Proceed with the determination according to the method in Chapter II of the International Oenological Codex.

Content should be less than 1 mg/kg the suitable preparation described in point 3.

4.6.    Total viable yeasts

Proceed with counting according to the method in Chapter II of the International Oenological Codex. Content should comply with the characteristics described in point 3.

4.7.    Yeasts of genera/species/strains other than the genera/species/strains indicated on the label

The genera, species and strains indicated on the packaging should be at least 95% of the total yeast population.

See Annex 1.

4.8.    Moulds

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Content should be less than 103 CFU/g the suitable preparation described in point 3.

4.9.    Lactic acid bacteria

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Content should be less than 105 CFU/g of the suitable preparation described in point 3.

4.10. Acetic acid bacteria

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Content should be less than 104 CFU/g of the suitable preparation described in point 3.

4.11. Salmonella

Proceed with counting according to the method in Chapter II of the International Oenological Codex.

Absence should be checked on a 25 g sample.

4.12. Escherichia coli

Proceed with counting according to the method in Chapter II of the International Oenological Codex using the selective differential medium for Escherichia coli.

Absence should be checked on a 1 g sample.

4.13. Staphylococci

Proceed with counting according to the method in Chapter II of the International Oenological Codex. The presence of staphylococci is evaluated by an enrichment culture in a liquid Giolitti and Cantoni medium followed by a confirmation on a solid Baird Parker medium.

In the case that the Giolitti and Cantoni medium gives positive results, the presence of staphylococci is confirmed by isolation on a solid Baird Parker medium. A positive culture medium loop is used to inoculate solid BP mediums to obtain isolated colonies.

Absence should be checked on a 1 g sample.

4.14. Coliforms

Proceed with counting according to the method in Chapter II of the International Oenological Codex using a selective differential medium for coliforms, desoxycholate gelose.

Number should be less than 102 CFU/g of the suitable preparation described in point 3.

  1. Additives

These must be in conformity with regulations in force.

  1. Storage conditions

Products must be stored and propagated under conditions which favour their genetic stability.

Always refer to manufacturer’s recommendations.

  1. Product documentation

Product documentation should specify guidelines about storage, transportation, handling and application conditions (temperature, activation, rehydration when needed, possibly in suitable must or wine suspensions, etc.).

Annex 1

  1. Obtention of colonies

Sample 1 g, and suspend it under sterile conditions in 100mL sterile saccharose 5%. Homogenise and allow standing at 25-30 °C for 20 min.

After adequate serial decimal dilutions, spread 0.1 mL of the diluted sample onto the surface of a nutrient YEPD agar plate (Glucose 20 g, Peptone 20 g, Yeast extract 10 g, 100 mg chloramphenicol to suppress bacterial growth and 150 mg biphenyl to suppress mould growth, Agar-agar 20 g, Water q.s.p. 1000 mL). Incubate for 6 days at 25 °C in aerobiosis. All yeast can grow, regardless of the species present.

  1. Identification of contaminant genera/species/strains

Identification is carried out on the colonies isolated on plates.

As required in the characteristics, the contaminant population (which is neither the pure strain nor the different strains in case of mixed strains) should be less than 5% of the total population. After the dilutions needed to obtain individual colonies, if 20 colonies out of 300 are identified,  a contaminant at 5% (ideally) should represent 1 colony out of 20.

The contaminant is identified based on the species, and therefore the genus, by D1/D2 sequencing (see 2.1). If all of the colonies are of the same species, it is possible to verify that a contaminant strain corresponds to less than 5% through analysis of 20 colonies, using SSR (see 2.2).

If the preparation is a blend of 2 or 3 species/strains, the least represented is 15% of the total. The verification of the composition of the mix by identification of colonies is not appropriate. Indeed, for 2 strains in the blend, the less represented should produce 3 colonies out of 20 identified, picked up out of 400 on the plate.

Therefore it can be suggested that the checking for 2 or even more species in blend (proportion of the different species ), use the quantitative specific PCR with probes targeting each of the expected species. In this case there is no preliminary plate culture. DNA is extracted directly from the sample.

 For controlling blends of same species strains (proportion of the different strains) the only possibility up to date cannot exclude the plate culture is and identification of colonies to the strain level; the result needs to be interpreted with precaution since the representation of each strain on the plates is affected by the growth ability on the one hand and on the other by the excessively low number of colonies that can reasonably be identified.

2.1.    Identification of the species

The species is identified by DNA sequencing of the variable domain D1/D2 of26S ribosomal region obtained by PCR amplification. It is the “method of choice” for yeast species identification: strains with more than a 1% sequence divergence of the domain D1/D2 of 600 nucleotides are not of the same species.

  • Suspend separately, colonies directly in the PCR mixture, or previously in water (about 50 µL depending on the size of the colony) and add a sample to the PCR mixture;
  • PCR mixture (final volume 50 μL): 10 mM Tris HCl pH 8, 50 mM KCl, 0.1% Triton X100 v/v, 0.2 mg/mL BSA, 3.12% v/v glycerol, 1.5 mM MgCl2, 200 μM dNTPs, 0.1 U/ μL Taq polymerase;
  • primers: NL1/NL4. NL 1 (5'-GCATATCAATAA GCGGAGGAAAAG) and NL 4 (5'-GGTCCGTGTTTCAA GACGG);
  • amplification is performed, after 10 min at 95 °C to make accessible DNA, by 30 cycles comprising the steps, 95 °C for 1 min, 55 °C for 45 s, 72 °C for 1 min, then a final step at 72 °C for 7 min;
  • PCR product is purified by any “PCR purification kit” and sequenced using the primers used for the amplification;
  • sequences obtained are compared to those available in the Genebank database (www.ncbi.nih.gov./Genbank).

2.2.    Identification of a strain

When the species is identified, it is possible to identify the strains. For most wine yeast species, at least the main ones used as starters, the most reliable and accurate method for identification is based on the analysis of sequence repeats (microsatellites SSR). Strains differ by the number of repetitions of short sequences at certain point of their genome. These loci are delimited by conserved regions that are chosen as primers for PCR amplification. The analysis consists in PCR amplification of several loci, with suitable primers for each yeast species, and measurement of their length by capillary electrophoresis for sequencing (with a degree of resolution of a single nucleotide).

Note:

  • at the time of writing strain typing is not possible for all yeast species;
  • in order to further the advances in knowledge, suitable primers for each yeast species are chosen by referring to studies published in international peer-review scientific journals;
  • for some species about 9-12 loci are analysed; some loci are more discriminant than others;
  • the analysis can be simplified by considering first a smaller number of loci chosen for their better discriminating power, and continuing the analysis in case of ambiguity;
  • amplification can be done in multiplex, which shortens and simplifies the analysis.

Inactivated yeasts

COEI-1-INAYEA Inactivated yeasts

  1. Object, origin and scope of application

Inactivated yeasts are used as nutrients for yeasts at the beginning of and during alcoholic fermentation, and also to encourage the rehydration of active dry yeasts. They can help to reduce the level of Ochratoxin A in the steps for wine maturing and clarification operations.[1]

They are produced by the biomass of Saccharomyces spp., inactivated by heat and/or by modification of the pH. They may have undergone the beginnings of a natural autolysis through the action of the endogenous enzymes. Production techniques are those conventionally used for the biomass of yeasts. In the process, there is no addition of antibiotics or of compounds other than those needed to grow the yeast.

When inactivated yeasts come from genetically modified yeasts, they must be authorised for use beforehand by the relevant authorities.

  1. Labelling

The label must indicate:

  • the name of the genus and the species of inactivated yeasts,
  • the organic nitrogen content,
  • any additives,
  • instructions for use,
  • the batch number as well as the expiry date, and the storage conditions in terms of well-defined temperature, humidity, and ventilation conditions,
  • the indication that the inactivated yeasts are derived from yeasts obtained by genetic modification and the modified characteristic if such is the case.
  1. Characteristics

In solid form they are usually available as granules, powder or flakes, of light to tan yellow in colour, with an odour characteristic of yeast.

Inactivated yeasts are partially soluble in water, the insoluble part being greater than or equal to 60% m/m of the dry matter.

  1. Limits and test methods

 

4.1 - Nitrogen content

4.1.1.  The total nitrogen content, expressed as element N, is less than 10% of the dry matter, according to the method of analysis described in Chapter II of the International Oenological Codex.

4.1.2.  The ammoniacal nitrogen content, expressed as element N, must be less than 0.5% of the dry matter and is determined according to the following method of analysis.

Place 1 g of dry matter in 100 mL of 0.5 M KCl and stir for 20-30 min. Introduce the 100 mL into the steam distillation apparatus described in Chapter II of the International Oenological Codex for the determination of total nitrogen, add 50 mL of 30% sodium hydroxide (R) and distil by collecting 250 mL in a conic flask containing 5 mL of 4% boric acid (R), 10 mL of water and 2-3 drops of methyl red-methylene blue mixed indicator (R).

Titrate the distillate with 0.1 M hydrochloric acid until the indicator turns pink-purple.

1 mL of hydrochloric acid solution corresponds to 1.4 mg of nitrogen N.

Where n is the number of ml poured:

100 g of inactive dry yeasts contain 0.14n g of ammoniacal nitrogen, expressed as element N.

4.1.3.  The organic nitrogen content is obtained through the difference between the total nitrogen content and the ammoniacal nitrogen content.

4.1.4.  The free and soluble amino-acids and small peptides content must be lower than 10% of dry matter in glycine equivalent, according to the DNFB method described in the appendix, or, if expressed as element N, must be 1.9% of the dry matter.

4.2.         Humidity

This is measured by the loss in weight of 5 g of product, dried at 105°C until the weight is constant (approximately 3 hours).

The maximum humidity must be less than 7%.

 

4.3.         Lead

Determination according to the method indicated in Chapter II of the International Oenological Codex

The lead content must be less than 2 mg / kg of dry matter.

4.4.         Mercury

Determination according to the method indicated in Chapter II of the International Oenological Codex

The mercury content must be less than 1 mg / kg of dry matter.

4.5.         Arsenic

Determination according to the method indicated in Chapter II of the International Oenological Codex

The arsenic content must be less than 3 mg / kg of dry matter.

4.6.         Cadmium

Determination according to the method indicated in Chapter II of the International Oenological Codex

The cadmium content must be less than 1 mg / kg of dry matter

4.7.         Viable yeasts

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

The viable yeast count must be less than or equal to 102 CFU / g.

4.8.         Moulds

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

The mould count must be less than 103 CFU / g of dry matter.

4.9.         Lactic bacteria

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

The lactic bacteria count must be less than 103 CFU / g of dry matter.

4.10.     Acetic bacteria

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

The acetic bacteria count must be less than 103 CFU / g of dry matter.

4.11.     Salmonella

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

Absence must be checked on a sample of 25 g of dry matter.

 

4.12.     Escherichia coli

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

Absence must be checked on a sample of 1 g of dry matter.

4.13.     Staphylococci

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

Absence must be checked on a sample of 1 g of dry matter.

4.14.     Coliforms

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

The coliform count must be less than 102 CFU / g of dry matter.

  1. Additives

They must comply with the currently applicable regulations.

  1. Storage

Inactivated yeasts must always be stored in sealed bags sheltered from the air. Store in a cool, dry place.

In all cases, refer to the manufacturer's instructions.

Appendix 1: Dinitrofluorobenzene method

 

  1. Introduction

 

This method is used to quickly determine the amino nitrogen in a biological solution compared with a standard range produced with a solution of glycine.

  1. Scope of application

 

Oenological products of plant or animal origin.

 

  1. Definition

 

Dinitrofluorobenzene (DNFB) reacts with free NH2 functions contained in the amino acids to give a bright yellow compound determined by colorimetry at 420 nm. The reaction takes place at a pH > 9.3.

  1. Reagents and Products

 

Reagents:

  • Borax or sodium tetraborate,
  • Dinitrofluorobenzene,
  • 10 M Hydrochloric acid,
  • Glycine.
  1. Apparatus
  • Haemolysis tubes,
  • Micropipettes,
  • Spectrophotometer for measurements in the visible range,
  • Water bath at 60°C.
  1. Sampling

 

Prepare a solution of 5% sodium tetraborate in pure water,

Prepare a DNFB solution: introduce 130 µL of DNFB in 10 mL of 95% vol. Ethanol,

Prepare a 2M hydrochloric acid solution,

Produce a standard range from a 2 g/L stock solution of glycine (M= 75.07 g) e.g. 0.50 mg/L, 100 mg/L, 200 mg/L, 500 mg/L,

Prepare a solution with 2 g/L of the product to be determined.

  1. Procedure

 

In a haemolysis tube, insert:

380 µL of 5% Borax,

20 µL of the sample to be determined,

20 µL of the DNFB solution,

Perform in identical fashion for the glycine range,

Stir and place in the water bath at 60°C for 30 min,

Add 3 mL of 2M HCl,

Stir and read the specific absorbance at 420 nm for the sample,

Produce a calibration curve with the Glycine range.

  1. Results

 

Plot the value of absorbance at 420 nm for the sample on the calibration curve.

The results are expressed in g/L of Glycine.


[1] Code of sound vitivinicultural practices in order to minimise levels of Ochratoxin A in vine-based products

Inactivated yeasts (glutathion)

COEI-1-LEVGLU Inactivated yeasts with guaranteed glutathione levels

  1. Object, origin and scope of application

These inactivated dry yeasts (IDY) with guaranteed glutathione levels are characterised by higher levels of reduced glutathione than those contained in standard inactivated yeasts. They are used to limit oxidation phenomena in musts and wines. The presence of reduced glutathione (GSH) may be accompanied by that of its precursors, cysteine and – in particular – gamma-glutamylcysteine.

Like classic inactivated dry yeasts, they also provide nutrients for yeasts at the start of and during alcoholic fermentation. They may help to reduce ochratoxin-A levels in wines during maturing and clarification operations[i] (Resolution OIV-OENO 459-2013).

They are derived from Saccharomyces and/or non-Saccharomyces species’ biomass, whose cultivation is managed so as to increase the natural production of reduced glutathione (GSH). They are therefore derived from pure cultures without any subsequent addition of glutathione or of cysteine and gamma–glutamyl-cysteine to the final product, what is attested by a ratio between gamma-glutamyl-cysteine and GSH that must be superior to 20%.

They are inactivated by heat and/or by pH modification. They may have been subjected to the start of natural autolysis under the action of endogenous enzymes. No antibiotics or other compounds are added in the process other than those necessary for yeast growth.

When the inactivated yeasts come from genetically engineered yeasts, these must have received the preliminary authorisation of the relevant authorities.[1]

  1. Labelling

The following must appear on the label:

  • the name of the genus and species of the inactivated yeasts with guaranteed glutathione levels,
  • the minimum content , expressed in mg/g of inactivated dry yeasts (IDY), of reduced glutathione
  • the maximum content, expressed in mg/g of inactivated dry yeasts (IDY), of cysteine
  • the maximum content, expressed in mg/g of inactivated dry yeasts (IDY), of gamma-glutamyl-cysteine,
  • the organic nitrogen content,
  • any additives,
  • the instructions for use,
  • the batch number as well as the expiry date and storage conditions such as temperature, humidity and aeration conditions,
  • the indication that the inactivated yeasts come from genetically engineered yeasts, and the modified character if this is the case.
  1. Characteristics

They are most often in the form of granules, powder or flakes, of light yellow to yellow ochre, with a smell characteristic of yeast. Inactivated yeasts with guaranteed GSH levels are partially soluble in water, with the insoluble part being greater or equal to 60% m/m of the dry matter.

  1. Limits and trial methods

4.1.     Oxidised glutathione (GSSG) content

The level of oxidised form of glutathione, glutathione disulphide (GSSG) that is the only identified form according to the state of our knowledge, is measured by the HPLC method described in Annex 1.

4.1.1.  Preparation of the solution for testing

Precisely weigh 2 g IDY and place in a 20-mL centrifuge tube, add 1 mL glass beads of 425-600 microns and 4 mL pH 7.5 phosphate buffer solution.

Vortex for 20 min at 4°C then centrifuge a minimum of 12,000 g for 20 min at 4°C.

The supernatant is the solution for testing, which is to be kept in the dark at 4°C for 4 hrs maximum before determination.

The ratio between reduced gluthatione and oxidised glutathione should be higher than3.

4.2.     Reduced glutathione (GSH), Cysteine and gamma-glutamylcysteine content

The reduced glutathione, cysteine and gamma-glutamylcysteine levels are measured by the HPLC method after derivatisation described in Annex 4.

The reduced glutathione content should be greater than 1%, or 10 mg/g IDY

The endogenous cysteine content should be lower than 0.3%, or 3 mg/g IDY,

the gamma-glutamylcysteine content should be lower than 1%, or 10 mg/g IDY.

4.3.     Nitrogen content

4.3.1.  The total nitrogen content, expressed as element N, is less than 10% of the dry matter, according to the method of analysis described in Chapter II of the International Oenological Codex, being referred to as Nt

4.3.2.  The ammoniacal nitrogen content, expressed as element N, must be less than 0.5% of the dry matter and is determined according to the method of analysis described in Annex 2, being referred to as Na

4.3.3.  The organic nitrogen content is obtained by the difference between the total nitrogen content and the ammoniacal nitrogen content:

Organic nitrogen = Nt-Na

4.3.4.  The small peptide and free and soluble amino acid content should be less than 10% of the dry matter in glycine equivalent, according to the DNFB method described in Annex 3, or 1.9% of the dry matter expressed as element N.

4.4.     Humidity

This is measured by the 5 g loss in product weight, dried at 105 °C to constant weight (around 3 hours).The maximum content should be less than 7%.

4.5.     Lead

Proceed with an analysis according to the method that appears in Chapter II of the International Oenological Codex.

The content should be less than 2 mg/kg of the dry matter.

4.6.     Mercury

Proceed with an analysis according to the method that appears in Chapter II of the International Oenological Codex.

The content should be less than 1 mg/kg of the dry matter.

4.7.     Arsenic

Proceed with an analysis according to the method that appears in Chapter II of the International Oenological Codex.

The content should be less than 3 mg/kg of the dry matter.

4.8.     Cadmium

Proceed with an analysis according to the method that appears in Chapter II of the International Oenological Codex.

The content should be less than 1 mg/kg of the dry matter.

4.9.     Viable yeasts

Proceed with counting according to the method that appears in Chapter II of the International Oenological Codex.

The number should be less than or equal to 102 CFU/g of the dry matter.

4.10. Mould

Proceed with counting according to the method that appears in Chapter II of the International Oenological Codex.

The number should be less than 103 CFU/g of the dry matter.

4.11. Lactic acid bacteria

Proceed with counting according to the method that appears in Chapter II of the International Oenological Codex.

The number should be less than 103 CFU/g of the dry matter.

4.12. Acetic bacteria

Proceed with counting according to the method that appears in Chapter II of the International Oenological Codex.

The number should be less than 103 CFU/g of the dry matter.

4.13. Salmonella

Proceed with counting according to the method that appears in Chapter II of the International Oenological Codex.

Absence should be checked on a 25 g sample of the dry matter.

4.14. Escherichia coli

Proceed with counting according to the method that appears in Chapter II of the International Oenological Codex.

Absence should be checked on a 1 g sample of the dry matter.

4.15. Staphylococci

Proceed with counting according to the method that appears in Chapter II of the International Oenological Codex.

Absence should be checked on a 1 g sample of the dry matter.

4.16. Coliforms

Proceed with counting according to the method that appears in Chapter II of the International Oenological Codex.

The number should be less than 102 CFU/g of the dry matter.

  1. Additives

These should be compliant with the regulations in force.

  1. Preservation

Do not store in open packaging. The inactivated yeasts with guaranteed glutathione levels should always be kept in sealed sachets without air contact. Store in a cool, dry place. Follow the manufacturer’s instructions at all times. Storage under unappropriated conditions might lead to the decrease of the reduced glutathione content.

Annex 1: Determination of reduced and oxidised glutathione by HPLC

 

This determination is carried out according to the method for the determination of glutathione in pharmaceutical preparations by Soliman et al. (2014).

  1. Scope of application

This method makes it possible to determine the reduced glutathione and oxidised glutathione or glutathione disulphide (GSSG) levels within a concentration range of 0-100 mg/L of preparation for analysis.

  1. Principle

The method used employs high-performance liquid chromatography according to the reverse-phase principle (column C18) with detection by spectrophotometry using diode-array apparatus of 200-400 nm.

  1. Products and reagents

 

3.1.     List of products

3.1.1.  Glutathione (GSH, > 98%)

3.1.2.  Methanol (HPLC-grade purity)

3.1.3.  Formic acid (purity > 98%)

3.1.4.  Ultra-pure water with resistivity of >18 M.cm at 25°C temperature.

3.2.     Mobile phase

The mobile phase is constituted of ultra-pure water (3.1.4) containing 0.1% of the formic-acid mixture (3.1.3) and methanol (3.1.2) in proportions of 90:10, v/v.

  1. Equipment

4.1.     High-performance liquid chromatography apparatus

4.2.     Diode-array spectrophotometer

4.3.     Data-acquisition apparatus

4.4.     Octadecyl-type column of dimensions 150 mm x 2 mm and with a 3-µm diameter (by way of example)

4.5.     230-µL Loop injector

4.6.     System for degassing of solvents (ultrasonic)

4.7.     System for filtration of samples on a membrane with pores of 0.45 μm in diameter.

  1. Preparation of samples

5.1.     The sample containing the glutathione to be determined is prepared by dilution of the solution for testing (point 4.1.1 of the monograph) in the mobile phase (3.2) in order to obtain a final concentration of around 20 mg/L.

5.2.     The samples are filtered on a membrane (4.7) before injection.

  1. Procedure

Analysis is conducted at room temperature, in isocratic mode with a mobile-phase flow rate of 0.5 mL/min.

Detection is carried out in "scan" mode at 200-400 nm.

  1. Results

Under these analytical conditions, reduced glutathione (GSH) is well separated from oxidised glutathione (GSSG). This method consequently allows both forms of glutathione to be determined.

Under these analytical conditions, the retention time of glutathione is 7.5 min and that of oxidised glutathione is 9.5 min.

  1. Method characteristics

Each concentration is calculated by averaging the three determinations obtained by using the regression line of the calibration curve. The results are expressed in mg/L.

The linear regression and correlation coefficient are calculated according to the least-squares method.

Linearity

  • The linear range is 0-100 mg/L and the R correlation coefficient = 0.9998.

Precision

  • The method precision was evaluated based on 3 analyses of glutathione at 1.0, 50.0 and 100.0 mg/L, conducted within the same day and also on 3 different days.

Table 1: Characteristics of the method for the determination of reduced glutathione based on the recovery rates

 

Daily precision

Precision over 3 days

GSH concentration (mg/L)

% recovery, SD

% CV

% recovery, SD

% CV

1

99.88 ± 0.68

0.68

99.76 ±1.89

1.89

50

100.04 ± 0.39

0.39

100.09 ± 0.73

0.73

100

99.93 ± 0.57

0.57

99.85 ± 0.86

0.86

Scope of application

  • According to the determinations carried out, the method is applicable for concentrations of 0-100 mg/L.

The limits of detection and quantification of glutathione established according to the guidelines of the International Conference on Harmonisation (ICH) (3.3 and 10 times the standard deviation of the blank [7 analyses] divided by the slope of the calibration curve) are 20 μg/L (LoD) and 68 μg/L (LoQ) respectively.

  1. Bibliography
  • Soliman, R. M., Hadad, G. M., Abdel Salam, R.A., Mesbah, M. K., 'Quantitative determination of glutathione in presence of its degradant in a pharmaceutical preparation using HPLC-DAD and identification by LC-ESI-MS', J. Liquid Chromatography and related technologies, 37, 2014, pp. 548-559.

Annex 2: Determination of ammoniacal nitrogen

  1. Reagents

1.1.     Potassium chloride (0.5 M KCl)

Dissolve 18.64 g KCl in 500 mL pure, demineralised water.

1.2.     30% Sodium hydroxide

Place 30 g sodium hydroxide in a 100-mL flask, add 70 mL pure, demineralised water, stir until dissolved and make up to 100 mL.

1.3.     4% Boric acid (R)

See R part II of the International Oenological Codex.

1.4.     M Hydrochloric acid for titration (solution ready for market use)

1.5.     Mixed indicator of methyl red and methylene blue

See R part II of the International Oenological Codex.

  1. Equipment

2.1.     Laboratory glassware

2.2.     Steam distillation apparatus as described in Chapter II of the International Oenological Codex for the determination of total nitrogen.

  1. Determination

3.1.     Place 1 g of the dry matter of the inactivated yeasts in 100 mL 0.5 M KCl (1.1) and mix for 20-30 min.

3.2.     Introduce the 100 mL into the steam distillation apparatus (2.2) with 50 mL 30% sodium hydroxide (R).

3.3.     Distil by collecting 250 mL in a conical flask containing 5 mL 4% boric acid (1.3), 10 mL water and 2-3 drops of mixed indicator of methyl red and methylene blue (1.5).

Titrate the distillate using 0.1 M hydrochloric acid (1.4) up to the purple-pink bend of the indicator.

1 mL hydrochloric acid solution corresponds to 1.4 mg nitrogen (N).

Where n is the number of mL poured:

100 g IDY contain 0.14 n g ammoniacal nitrogen expressed as element N, namely Na.

Annex 3:Amino nitrogen method

  1. Introduction

This method makes it possible to quickly determine the amino nitrogen in a biological solution compared with a calibration range produced with glycine solution.

  1. Scope of application

Oenological products of plant or animal origin.

  1. Definition

Dinitrofluorobenzene or DNFB reacts with the free NH2 groups contained in the amino acids in order to give a compound with a bright yellow colour determined by 420-nm colorimetry. The reaction takes place at a pH > 9.3.

  1. Reagents and products

4.1.     Reagents:

4.1.1.  borax or sodium tetraborate,

4.1.2.  dinitrofluorobenzene (be careful of hazards while handling DNB),

4.1.3.  10 M hydrochloric acid,

4.1.4.  glycine, purity ≥ 98%,

4.1.5.  ethanol 95% vol.

  1. Apparatus

5.1.     Haemolysis tubes,

5.2.     micropipettes,

5.3.     spectrophotometer for measurements in the visible region,

5.4.     60 °C water bath.

  1. Preparation of samples
    1.      Prepare a 5% sodium tetraborate solution in pure water.
    2.      Prepare a DNFB solution: introduce 130 μL DNFB in 10 mL ethanol of 95% vol.,
    3.      Prepare a 2 M hydrochloric acid solution,
    4.      Create a calibration range from a 2 g/L glycine stock solution (M=75.07 g) e.g. 0.50 mg/L, 100 mg/L, 200 mg/L, 500 mg/L,
    5.      Prepare a 2 g/L suspension of the product to be determined, centrifuge for 30 min and recover the supernatant.
  1. Procedure

 

Introduce the following into a haemolysis tube:

  • 380 μL 5% borax (6.1),
  • 20 μL sample to be determined (6.5)
  • 20 μL DNFB solution (6.2),

Do the same for the glycine range,

Mix and place the water bath at 60°C for 30 min (5.4),

Add 3 mL 2M HCl (6.3),

Mix and read the specific absorbance at 420 nm for the sample (5.3),

Produce a calibration range with the glycine range (6.4).

  1. Results

Record the absorbance value of the sample at 420 nm on the calibration curve. The results are expressed in g glycine/L.

Annex 4: Determination of reduced glutathione, cysteine and gamma-glutamylcysteine by HPLC after derivatisation

 

Preambule

The principle is to determine, by HPLC/UPLC-UV using a reverse-phase column, amino acids and thiol peptides after derivatisation of this function. This method is suitable for complex matrices of yeasts and yeast derivatives.

  1. Scope of application

This method allows for the determination of reduced glutathione (GSH), cysteine (Cys) and gamma-glutamylcysteine (GluCys) within the following concentration ranges:

  • 2-24 mg/L for the GSH and GluCys compounds,
  • 0.5-6 mg/L for Cys.
  1. Principle

The method used employs high-performance liquid chromatography according to the reverse-phase principle (column C18) with detection by spectrophotometry at 320 nm.

  1. Products and reagents

3.1.     Products

3.1.1.  GSH: glutathione, CAS no. 70-18-8 (purity > 98%)

3.1.2.  Cys.HCl.H20: L-cysteine hydrochloride monohydrate, CAS no. 7048-04-6 (purity > 98%)

3.1.3.  GluCys: γ-L-glutamyl-L-cysteine, CAS no. 636-58-8 (purity > 80%)

3.1.4.  Sodium dihydrogen phosphate (NaH2PO4·H2O), pure

3.1.5.  Sodium acetate anhydrous, pure

3.1.6.  17.4 M Acetic acid, pure

3.1.7.  Methanol (HPLC-grade purity)

3.1.8.  Concentrated phosphoric acid (purity > 98%)

3.1.9.  Ultra-pure water of resistivity >18 M.cm at a temperature of 25°C

3.1.10.     Acetonitrile, pure

3.1.11.     2,2’-Dithiobis(5-nitropyridine) (DNTP), CAS no. 2127-10-8 (purity > 96%)

3.1.12.     Concentrated trichloroacetic acid solution (25-30%)

3.2.     Acetate buffer (used for derivatisation)

  • Weigh 8.1 g sodium acetate (3.1.5), dissolve into 100 mL ultra-pure water (3.1.9),
  • adjust the pH to 6.3 with acetic acid (3.1.6) (around 100-200 µL),
  • make up to 1 L with ultra-pure water (3.1.9).
    1.      2,2’-Dithiobis(5-nitropyridine) (DNTP) reagent (to be prepared just before use)
  • Weigh 30 mg DNTP (3.1.11) and dissolve in 10 mL acetonitrile (3.1.10).
    1.      Trichloroacetic acid at 5.7%
  • Dissolve 19 g trichloroacetic acid at 30% (3.1.12) in 100 mL ultra-pure water (3.1.9).
    1.      Mobile phase
  • Eluent A: weigh 3.4g NaH2PO4·H2O (3.1.4), dissolve in 898 g ultra-pure water (3.1.9), add 79 g methanol (3.1.7), and adjust the pH from 4.45 to 2.5 by addition of concentrated phosphoric acid (3.1.8; around 0.8-1 mL).
  • Eluent B: methanol (3.1.7).
  1. Equipment

4.1.     High-performance liquid chromatography apparatus

4.2.     Spectrophotometer with detection at 320 nm

4.3.     Data-acquisition apparatus

4.4.     Otadecyl-type column with dimensions of 250 mm x 4.6 mm with a phase diameter of 5 μm (e.g. RP Supelcosil ABZ+Plus; Waters XTerra RP18 or equivalent)

4.5.     Loop injector

4.6.     System of degassing of solvents (ultrasound)

4.7.     Sample filtration system on a membrane with 0.45- μm pore diameter

4.8.     Magnetic stirrer

4.9.     Centrifuge

4.10. pH meter

4.11. Everyday laboratory glassware

  1. Preparation of samples

5.1.     Preparation of standards

5.1.1.  GSH solution at ~400 mg/L

  • In a 200-mL flask, dissolve ~80 mg GSH (3.1.1) weighed exactly, and make up to 200 mL using ultra-pure water (3.1.9).
    1.   GluCys solution at ~400 mg/L
  • In a 50-mL flask, dissolve ~20 mg GluCys (3.1.3) weighed exactly, and make up to 50 mL using ultra-pure water (3.1.9).
    1.   Cys.HCl.H20 solution at ~100 mg/L
  • In a 100-mL flask, dissolve ~130 mg Cys,HCl.H2O (3.1.2) weighed exactly, make up to 100 mL using ultra-pure water (3.1.9), then dilute to 1:10 with ultra-pure water (3.1.9).
    1.      Preparation of samples

The test portion (TP) of the sample should be adapted so that the concentration is within the calibration range, i.e. between 2 and 24 mg/L GSH. For inactivated dry yeast (IDY) with guaranteed GSH levels, take a sample in advance according to the following protocol:

  • weigh ~1g IDY exactly, add 17.5 mL trichloroacetic acid at 5.7% (3.4),
  • mix for 20 min at room temperature (4.8),
  • adjust to 50 mL (=V) with ultra-pure water (3.1.9),
  • centrifuge for 10 min at 5500 rpm (4.9).
  1. Derivatisation
  • Carry out in test tubes based on the preparations in 5.1, according to the following table.
  • Mix by inverting the tubes.

The reaction is complete in 5 minutes. The different solutions are analysed by HPLC after filtration (4.7).

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Description générée automatiquement

Important note: Consider adapting the test portion according to the colouration. Verify that the tests fall within the range.

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Description générée automatiquement

Time after injection (min)

% eluent A

% eluent B

 

100

0

1

100

0

23

40

60

28

0

100

32

0

100

34

100

0

  1. Calibration curves

For each analyte, establish calibration curves C (mg/L) = f[A] considering the following:

  • the concentrations in mg/L for Cys, GSH and GluCys,
  • the factor of dilution,
  • the areas obtained.

Important note: For Cys, take into consideration the HCl: PE (g/L) * Mpure Cys  (121.16 g/mol) / MCys,HCl.H2O (175.63 g/mol).

Calculations of concentrations:

In terms of dry matter (DM):

In terms of the product as it is:

  1. Bibliography
  • Rahman et al., Nature Protocols 1, 2007, pp. 3159-3165.
  • Katrusiac et al., ‘Pre-column derivatization high-performance liquid chromatographic method for determination of cysteine, cysteinyl–glycine, homocysteine and glutathione in plasma and cell extracts’, Journal of chromatography B: Biomedical Sciences and Applications, Vol. 758, No. 2, 2001, pp. 207-212.
  • Raju N. Appala et al., ‘A Simple HPLC-UV Method for the Determination of Glutathione in PC-12 Cells’, Scientifica, Vol. 2016 (2016).

[1] Code of good vitivinicultural practices in order to minimise the presence of OTA in vine-based products.


 

Yeast autolysates

COEI-1-AUTLYS Yeasts autolysates

  1. Object, origin and scope of application

Yeast autolysates are used as nutrients during the rehydration of dry active yeasts intended for alcoholic fermentation, and also as nutrients during alcoholic fermentation. Yeast autolysates are derived from Saccharomyces spp. yeast biomass. They are obtained from yeast biomass through autolysis, in some cases combined with heat treatment and/or modification of the pH. Autolysis is defined as the self-digestion of proteins and other cell tissues by the enzymes contained within the yeast cells.

The micro-organism production techniques are those conventionally used for yeast biomasses. There is no addition of antibiotics or compounds during the process other than those required for yeast growth. If the autolysates come from genetically modified yeasts, the yeasts must be submitted for prior authorisation by the competent authorities.

  1. Labelling

The label must indicate:

  • the name of the genus and the species of the yeast autolysate,
  • the organic nitrogen content,
  • the amino acid content,
  • any additives,
  • instructions for use,
  • the batch number, the expiry date, and the storage conditions in terms of well-defined temperature, humidity and ventilation conditions,
  • if applicable, the indication that the autolysates were obtained from genetically modified yeasts, and the modified characteristic.
  1. Characteristics

In solid form they are available as powder, flakes or granules, light yellow to brown in colour, with an odour characteristic of yeast. In liquid form, they are available in tan to brown colour.

Yeast autolysates are highly water-soluble. The soluble part is less than 80% of the dry matter. The soluble part of the dry matter present in the liquid autolysate must also be less than 80%.

  1. Limits and test methods

4.1.    Nitrogen

4.1.1.  The total nitrogen content, expressed as element N, must be less than 12% of the dry matter according to the method of analysis described in Chapter II of the International Oenological Codex.

4.1.2.  The ammoniacal nitrogen content, expressed as element N, must be less than 0.5% of the dry matter. It is determined by the following method.

Place 1 g of dry matter in 100 mL of 0.5 M KCl and stir for 20-30 min. Introduce the 100 mL into the steam distillation apparatus described in Chapter II of the International Oenological Codex for the determination of total nitrogen, add 50 mL of 30% sodium hydroxide (R) and distil by collecting 250 mL in a conic flask containing 5 mL of 4% boric acid (R), 10 mL of water and 2-3 drops of methyl red-methylene blue mixed indicator (R). Titrate the distillate with 0.1 M hydrochloric acid until the indicator turns pink-purple.

1 mL of hydrochloric acid solution corresponds to 1.4 mg of nitrogen N.

Where n is the number of mL poured: 100 g of yeast autolysates contain 0.14n g of ammoniacal nitrogen, expressed as element N.

4.1.3.  Organic nitrogen equals total nitrogen minus ammoniacal nitrogen.

4.1.4.  The amino acid content, in glycine equivalent, must be between 10% and 20% of dry matter, according to the DNFB method described in the appendix, or, if expressed as element N, must be between 1.9% and 3.7% of the dry matter.

4.2.    Humidity

Measured by the loss in weight of 5 g of product, dried at 105°C until the weight is constant (approximately 3 hours)

The maximum humidity of the solid forms must be less than 7%.

Heavy metal limits concern the dry matter of the dry and liquid forms.

4.3.    Lead

Determination according to the method indicated in Chapter II of the International Oenological Codex

The lead content must be less than 2 mg/kg of dry matter.

4.4.    Mercury

Determination according to the method indicated in Chapter II of the International Oenological Codex

The mercury content must be less than 1 mg/kg of dry matter.

4.5.    Arsenic

Determination according to the method indicated in Chapter II of the International Oenological Codex

The arsenic content must be less than 3 mg/kg of dry matter.

4.6.    Cadmium

Determination according to the method indicated in Chapter II of the International Oenological Codex

The cadmium content must be less than 1 mg/kg of dry matter.

4.7.    Viable yeasts

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

The viable yeast count must be less than or equal to 102 CFU/g or per mL for the liquid form.

4.8.    Moulds

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

The mould count must be less than 103 CFU/g or per mL for the liquid form.

4.9.    Lactic bacteria

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

The lactic bacteria count must be less than 103 CFU/g or per mL for the liquid form.

4.10. Acetic acid bacteria

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

The acetic acid bacteria count must be less than 103 CFU/g or per mL for the liquid form.

4.11. Salmonella

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

Absence must be checked on a sample of 25 g, or mL for the liquid form.

4.12. Escherichia coli

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

Absence must be checked on a sample of 1 g, or mL for the liquid form.

4.13. Staphylococci

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

Absence must be checked on a sample of 1 g, or mL for the liquid form.

4.14. Coliforms

Enumerate according to the method indicated in Chapter II of the International Oenological Codex

The coliform count must be less than 102 CFU/g or per mL for the liquid form.

  1. Additives

 

They must comply with the currently applicable regulations.

  1. Storage

Yeasts autolysates must always be stored in sealed bags sheltered from the air. Store in a cool, dry place.

In all cases, refer to the manufacturer's instructions.

Appendix 1: Dinitrofluorobenzene method

  1. Introduction

This method is used to quickly determine the amino nitrogen in a biological solution compared with a standard range produced with a solution of glycine.

  1. Scope

Oenological products of plant or animal origin

  1. Definition

Dinitrofluorobenzene (DNFB) reacts with free NH2 functions contained in the amino acids to give a bright yellow compound determined by colorimetry at 420 nm. The reaction takes place at pH> 9.3.

  1. Reagents and Products

Reagents:

  • Borax or sodium tetraborate,
  • Dinitrofluorobenzene,
  • 10 M Hydrochloric acid,
  • Glycine.
  1. Equipment

 

  • haemolysis tubes,
  • micropipettes,
  • Visible spectrophotometer,
  • Water bath at 60°C.
  1. Sampling

 

  • Prepare a solution of 5% sodium tetraborate in pure water,
  • Prepare a solution with DNFB: introduce 130 μl of DNFB in 10 mL of 95% ethanol,
  • Prepare a solution of hydrochloric acid 2M,
  • Produce a standard range from a stock solution of glycine with 2 g/l (M = 75.07 g) e.g. 0.50 mg/l, 100 mg/l, 200 mg/l, 500 mg/l,
  • Prepare a solution with 2 g/l of the product to be titrated.
  1. Procedure

 

In a test tube, insert:

  • 380 μl of 5% Borax,
  • 20 μl of the sample to be titrated,
  • 20 μl of the DNFB solution,
  • perform in identical fashion with the glycine range,
  • Stir and place in water bath at 60°C for 30 min,
  • Add 3 mL of HCL 2M,
  • Stir and read the specific absorbance at 420 nm for the sample,
  • Produce a calibration curve with the Glycine range.
  1. Results

 

Plot the value of absorbance at 420 nm for the sample on the calibration curve.

The results are expressed in g/l of Glycine.

Yeast hulls

COEI-1-YEHULL Cellular yeast hulls (Yeast walls)

  1. Object, origin and field of application

The cellular yeast hulls are obtained from Saccharomyces spp. yeasts. The preparation mode must respect the surface area and consequently the adsorption capacity.

Cellular yeast hulls are found in fine powder or microgranulate forms, non-hygroscopic, cream coloured and slightly odorous. They do not leave harmful residues in grape musts and in wines. During the process, there is no addition of antibiotics or compounds other than those needed for the yeast to grow.

Cellular yeast hulls are packed under conditions which prevent oxidation.

They are used to prevent and deal with stuck fermentations. They have the property of fixing certain fatty acids (octanoic and decanoic) which disturb membrane permeability of yeasts.

When the cellular yeast hulls come from genetically engineered yeasts, these must be subject to the prior authorisation of the relevant authorities.

There is an addition limit on the usage of cellular yeast hulls.

  1. Labelling

The label must include:

  • The name of the genus and species
  • The instructions for use
  • Any additives
  • The purity, batch number, expiry date and storage conditions under well-defined temperature, humidity and ventilation conditions
  • An indication whether the cellular hulls come from genetically engineered yeasts, and the modified character if this is the case.
  1. Composition of cellular yeast hulls (values)

Dry matter

≥ 94% m/m according to the method described in Annex 2

Carbohydrates

> 40% m/m

Carbohydrates:

The total glucans and mannans content must be more than 60% of the total carbohydrates according to the method described in Annex 1.

Solubility

< 10% m/v

  1. Additives and ingredients

According to legislation.

  1. Limits and trial methods

5.1.    Lead

Proceed with an analysis according to the method described in Chapter II of the International Oenological Codex.

The content must be less than 2 mg/Kg.

5.2.    Mercury

Proceed with an analysis according to the method described in Chapter II of the International Oenological Codex.

The content must be less than 1 mg/Kg.

5.3.    Arsenic

Proceed with an analysis according to the method described in Chapter II of the International Oenological Codex.

The content must be less than 3 mg/Kg.

5.4.    Cadmium

Proceed with an analysis according to the method described in Chapter II of the International Oenological Codex.

The content must be less than 1 mg/Kg.

  1. Microbiological analyses

6.1.    Revivable yeast

Proceed with counting according to the method described in Chapter II of the International Oenological Codex.

Content: Less than 100 CFU per g.

6.2.    Lactic bacteria

Proceed with counting according to the method described in Chapter II of the International Oenological Codex.

Content: Less than 103 CFU per g.

6.3.    Acetic bacteria

Proceed with counting according to the method described in Chapter II of the International Oenological Codex.

Content: Less than 103 CFU per g.

6.4.    Mould

Proceed with counting according to the method described in Chapter II of the International Oenological Codex.

Content: less than 103 CFU per g.

6.5.    Salmonella

Proceed with counting according to the method described in Chapter II of the International Oenological Codex.

Content: Absence checked on 25 g sample.

6.6.    Escherichia coli

Proceed with counting according to the method described in Chapter II of the International Oenological Codex.

Content: Absence checked on 1 g sample.

 

6.7.    Staphylococci

Proceed with counting according to the method described in Chapter II of the International Oenological Codex.

Content: Absence checked on 1 g sample.

6.8.    Coliforms

Proceed with counting according to the method described in Chapter II of the International Oenological Codex.

Content: Less than 100 CFU/g

  1. Hygiene

Yeast hulls are produced in compliance with good food manufacturing practices.

They must not have a rancid odour and should not give an abnormal flavour to the wine (yeast flavour).

  1. Activity

The stimulatory effect of yeast hulls is based on their capacity to adsorb certain toxic substances for yeasts, which they produce during the growth period. Decanoic acid is the greatest growth inhibitor.

Technological activity (TA) expressed in grams (g) of product can thus be evaluated by absorption of decanoic acid.

A gram of cellular yeast hulls added to 100 mL alcohol solution of 10% vol., pH 3.5, containing 2 mg/L decanoic acid should adsorb, after 24 hours of contact at 18‑22 °C, 50% of this acid.

Monitoring can be carried out by the determination of decanoic acid by chromatography in the gaseous phase with detection by flame ionization (GC/FID) in accordance with the following procedures provided as example:

  • chromatography apparatus,
  • polar capillary column, for example a FFAP type column, 50 m in length and 0.2 mm in interior diameter,
  • melted silica support,
  • programmed temperature of 60 °C to 180 °C, or 4 °C/min,
  • injected volume of 1 µL of hydro-alcoholic solution (10 % vol.) to 2 mg/L decanoic acid treated with yeast hulls,
  • heptanoic acid internal standard of 2 mg/L after adding,
  • reference solution: hydro-alcoholic solution (10% vol.) to 2 mg/L decanoic acid.
  1. Storage

The cellular yeast hulls must always be stored in airtight bags in a temperate environment.

Annex 1:Determination of glucans and mannans in cellular yeast hulls

 

The cellular yeast hulls are subjected to a pre-solubilisation with concentrated H2SO4 prior to hydrolysis with H2SO4 at 128 °C in an oven. This total hydrolysis of the glucans and mannans generates proportional quantities of glucose and mannose that are determined by Ionic Chromatography.

To eliminate the glycogen, the method must be preceded by a pre-washing of the sample with a 0.5 mole/L NaOH solution for 1 hour at room temperature, followed by a centrifugation and another washing with water).

  1. Materials and equipment
  • 100 mL capped flask (Duran or Schott Glass)
  • Tube
  • Polyethersulfone flter with average pore diameter of 0.45 μm
  • Oven
  • H2SO4 72%
  • Ionic chromatography system with pulsed amperometry detector containing a gold electrode
  • Vortex mixer
  • NaOH 32%
  • 100 mL and 50 mL volumetric flasks
  • Distilled water
  • HPLC grade Water
  • Ionic chromatography column (Metrosep Carb1 Metrohm or equivalent)
  1. Method

2.1.    Preparation of standards

  • Weigh 50 mg of glucose (note the exact weight Wglu) and 50 mg of mannose (note the exact weight Wman)
  • Go to step 2.3.

2.2.    Sample preparation

  • Weigh 50 mg of cellular yeast hulls (note the exact weight Wy)
  • Go to step 2.3.

2.3.    Pre solubilisation

  • Add 3.3 mL of H2SO4 72%
  • Mix the sealed tube with a Vortex mixer
  • Leave for one hour at ambient temperature and stir every 10 min

2.4.    Acid Hydrolysis

  • Pour the contents of the tube into a 100 mL flask
  • Add 40 mL of distilled water
  • Close the flask
  • Put the capped flask in an oven at 128°c and incubate for 3 hours
  • Take out the flask and cool it
  • Neutralize with 8.112 mL of NaOH 32%
  • Decant the contents of the flask into a 100 mL volumetric flask
  • Adjust to 100 mL with distilled water
  • Filter the solution through an Acrodisc IC filter

2.5.    Chromatography

2.5.1.  Preparation of standards

  • Take 2.5 mL of the hydrolysed glucose and mannose solutions obtained in 2.4.
  • Transfer to a 50 mL volumetric flask
  • Adjust with distilled water
  • Put in a chromatography vial for the autosampler
    1.   Sample preparation
  • Take 7.5 mL of hydrolysed material obtained in 2.4.
  • Transfer to a 50 mL volumetric flask
  • Adjust with distilled water
  • Put in a chromatography vial for the autosampler
    1.   Preparation of the mobile phase
  • Measure one litre of HPLC grade water.
  • Filter using a 0.45 μm membrane
  • Degas under vacuum for 1 h 30 min
  • Measure 7.57 mL of NaOH 51% into the flask intended for the mobile phase
  • Be careful to use only a polypropylene flask for the mobile phase
  • Add the 1 litre of degassed water
  • Stir using a magnetic stirrer
    1.   Calibration solutions for chromatography
  • Prepare, using HPLC grade water, solutions of glucose and mannose at 10 mg/L, 30 mg/L and 40 mg/L
  • Use them for calibrating the chromatography
    1.   Chromatographic Conditions
  • Condition the column using the mobile phase at a flow rate of 1 mL/min for 2 hours.
  • Inject 20 μ L of :
  • The three calibration solutions (§2.5.4.)
  • The standard solution
  • The standard solution
  • Calibrate the system with the calibration solution. Trace the calibration curves Area = f (concentration)

The chromatography equipment will give the concentration in mg/L for:

the standard solution:

the sample solution :

  1. Calculation

3.1.    Yield calculation

Calculate the recovery yield for the standard mannose and glucose solutions as follows:

Wman and Wglu are the measured weights of mannose and glucose in mg (See §2.1.)

  1. Concentration of mannans and glucans in cellular yeast hulls

Concentration of mannans in g% m/m:

Concentration of glucans in g% m/m:

Wy: weight of cellular yeast hulls (see § 2.2.)

Yman and Yglu: yields of mannose and glucose (see § 3.1.)

Annex 2: Determination of the percentage of insoluble dry matter

  1. Principle

The analysis consists in comparing the total dry matter (DM) of the cellular yeast hulls with the dry matter remaining (insoluble DM) after a hot wash.

  1. Material and reagents
  • 4200 rpm centrifuge and accessories
  • Scales at 1/10 mg
  • Weighing cabinet for DM (FST 350)
  • Oven at 105 °C +/- 1 °C
  1. Method

Obtaining the insoluble part of the cellular yeast hulls

In a calibrated centrifuge crucible, place around 10 g of cellular yeast hulls dried beforehand to constant weight in an oven at 105 °C. Note the exact weight, which is: M1.

Stir into very hot water (70 - 80 °C).

Mix well.

Centrifuge for 10 mins at 4200 rpm.

Discard the supernatant, mix into very hot water and centrifuge for 10 mins at 4200 rpm.

Perform the operation a third time.

Place the calibrated centrifuge crucible containing the centrifugation pellet in an oven at 105 °C to constant weight and weigh it. M2 is the weight of the washed and dried hulls which make up the insoluble DM

  1. Calculations

Percentage of insoluble dry matter

L(+) tartaric acid

COEI-1-LTARAC L(+) Tartaric acid

L-2,3-dihydroxybutanedioic acid

Dextrorotatory tartaric acid

Acidum tartaricum

COOH - CHOH - CHOH - COOH

= 150.1

SIN NO. 334

  1. Objective, Origin and Scope of Application

This is a natural acid extracted from grapes.  It is used to acidify musts and wines under conditions stipulated by regulation.

  1. Labelling

The label should indicate in a clear manner that the product is L-tartaric acid, sometimes written L(+)tartaric acid, since its rotatory power is positive. It must also indicate the purity percentage (greater than 99.5%) and storage requirements.

  1. Properties

 

Very solid colorless, transparent crystals which have a distinctly acidic flavor and containing no water of crystallization.

Melting point is 170 °C.

  1. Solubility

Water at 20 °C

highly soluble

Alcohol, 95% by vol.

379 g/l

Glycerol 

Soluble

Ethyl ether

very slightly soluble

  1. Rotary power

In an aqueous solution of 20 g per 100 ml

Specific rotatory power varies greatly with temperature and pH.

  1. Identifying Characteristics

6.1.    Verify total solubility in water. A 1% solution exhibits an acidic reaction  in the presence of methyl orange (R)

6.2.    Place 2 ml of concentrated sulfuric acid (R), 2 drops of sulforesorcinic reagent (R) and a very small crystal of tartaric acid (1-5 mg) in a test tube. Heat to 150 °C.  An intense violet coloration should appear.

6.3.    Add 2 ml of 5 pp 100 potassium acetate solution (R) to 5 ml of 10 pp 100 solution (m/v). A crystallized precipitate should form immediately.

6.4.    Place 5 ml chloroform or dichloromethane in a test tube.  Add 100-200 mg tartaric acid. Shake. Crystals should gather at the bottom of the tube.  Under these conditions, citric acid crystals will collect at the liquid surface.

  1. Tests

7.1.    Foreign Matter

Tartaric acid should be soluble without residue in its weight of water and in 4 times its weight of alcohol at 95% by volume.

7.2.    Sulfur Ash

As explained in the annex, use a precisely-weighed sample of approximately 2 g to determine sulfur ash concentration in the tartaric acid. This sulfuric ash concentration must not be greater than 1 g/kg.

7.3.    Preparing the Solution for Tests

Dissolve 10 g of tartaric acid in a quantity of water sufficient to produce 100 ml of solution.

7.4.    Chlorides

Add 14.5 ml of water, 5 ml of nitric acid diluted to 10 pp 100 (R), and 0.5 ml of 5 pp 100 silver nitrate solution (R) to 0.5 ml of the solution prepared for tests under Paragraph 7.3.  After 15 minutes of sitting in the dark, there should be no clouding; or else, any clouding that does appear should be less intense than that observed in a control prepared as indicated in the annex.  (Chloride content expressed in terms of hydrochloric acid should be less than 1 g/kg).

7.5.    Sulfates

Add 18 ml of water, 1 ml of hydrochloric acid diluted to 10 pp 100 (R), and 2 ml of 10 pp 100 barium chloride solution (R) to 1 ml of the solution prepared for tests under Paragraph 7.3. After 15 minutes of sitting in the dark, there should be no clouding,;or else, any clouding that does appear should be less intense than that observed in a control prepared as indicated in the annex. (Sulfate content expressed in terms of sulfuric acid should be less than 1 g/kg).

7.6.    Citric Acid

Add 5 ml of water and 2 ml of mercury (II) sulfate solution (R) to 5 ml of the solution prepared for tests under paragraph 7.3.  Bring to a boil and add several drops of 2 pp 100 potassium permanganate solution (R).  No white precipitate should form.

7.7.    Oxalic Acid and Barium (test)

Neutralize 5 ml of test solution prepared under Paragraph 7.3 by adding ammonium hydroxide. Add 2 drops of acetic acid (R) and 5 ml of a saturate calcium sulfate solution (R).The solution should remain clear. (Opalescence may appear by virtue of the precipitation of calcium oxalate or barium sulfate.)

7.8.    Oxalic Acid (quantitative analysis)

If the test conducted under 7.7 is positive, perform quantitative analysis of the oxalic acid.

Using the method described in the annex, determine oxalic acid content in the test solution (6.3). (Content expressed for oxalic acid should be less than 100 mg/kg after dessiccation).

7.9.    Iron

Add 1 ml of concentrated hydrochloric acid (R) and 2 ml of 5 pp 100 potassium thiocyanate solution (R) to 10 ml of the solution prepared for tests under Paragraph 7.3.  The resulting red coloration should be less intense than that observed in a control prepared using 1 ml of an iron (III) salt solution having a concentration of 0.010 g of iron per liter, 9 ml of water and the same quantities of the same reagents.  (Iron content should be less than 10 mg/kg).

It is also possible to determine iron content by atomic absorption spectrometry, using the technique detailed in the Compendium.

7.10. Lead

Using the technique in the Appendix, determine the lead content in the test solution (7.3). (Lead content should be less than 5 mg/kg).

7.11. Mercury

Using the technique described in the Annex, determine the proportion of mercury in the test solution (7.3). (Mercury content should be less than 1 mg/kg).

7.12. Arsenic

Using the technique described in the Annex, determine the proportion of arsenic in the test solution (7.3). (Arsenic content should be less than 3 mg/kg).

  1. Quantitative Analysis

 

In 10 ml water, dissolve a precisely-weighed test sample p weighing about 1 g L-tartaric acid. Titrate with a 1 M sodium hydroxide solution (R) in the presence of phenolphthalein (R). Let n be the number of milliliters used.

1 ml 1 M sodium hydroxide solution corresponds to 0.075 g L-tartaric acid.

Content in percent of L-tartaric acid of the product assayed :

  • 7.5 n.

The product used for wine-making must contain at least 99.5 pp 100 L-tartaric acid (dry product).

  1. Storage

L-tartaric acid should be stored in hermetically sealed containers.

Lysozyme

COEI-1-LYSOZY Lysozyme

Muramidase

N°SIN: 1105 (enzyme 3.2.1.17)

  1. Object, origin and field of application

Lysozyme (Chlorhydrate and Lysozyme) is an edible egg white extract from hens. It is used to inhibit bacterial growth and can be used in musts and wine. Doses are limited in level.

Lysozymes contain no substances, micro-organisms or collateral enzyme activities, which are:

  • harmful to the health,
  • harmful for the quality of the products treated,
  • lead to the formation of undesirable products or favour acts of fraud.
  1. Labelling

The concentration of the product must be indicated on the label, in addition to the security conditions, the preservation and the expiration date.

  1. Composition

Lysozyme is a natural polypeptide made up of 129 amino acids, out of which there are 21 aspartic acids, 5 glumatic acids, 12 alanines, 11 arginines, 8 cystines, 3 phenylalanines, 12 glycines, 6 isoleucines, 1 histidine, 8 leucines, 6 lysines, 2 prolines, 2 methionines, 10 serines, 3 tyrosines, 7 threonines, 6 tryptophanes and 6 valines.

The molecular mass of lysozyme is 14,700 Daltons.

The water content must be less than or equal to 6%.

  1. Characteristics

Lysozyme can be in crystal powder form, white, odourless with a mild taste.

  1. Solubility

Lysozyme is soluble in water and insoluble in organic solvents.

  1. Identifying characteristics

A 2% aqueous solution must have a pH between 3.0 and 3.6. An aqueous solution containing 25-mg/100 ml has a maximum absorption of 281 nm and a minimum of 252 nm.

  1. Enzyme activity

Enzyme activity is capable of hydrolysing a link between N-acetylmuramic acid and N-acetylglucosamine of gram positive bacteria cell walls. The minimum concentration for lysozyme is 95%. There is no secondary enzyme activity.

  1. Enzyme origin and means of production

Enzyme is extracted form edible hen egg white by a procedure of separating ion-exchange resin.

The microbiological purity guarantees the security for its usage in food. The egg white used in the preparation of enzymes are compatible with parameters established by inspection agencies and is treated in compliance with hygienic manufacturing procedures.

  1. Substances used as diluents, preservatives and additives

 

There are no substances used as preservatives as the crystalline form guarantees the stability.

  1. Trial tests

10.1.     Sulphuric ashes

As indicated in the appendix, the sulphuric ash content of lysozyme should not exceed 1.5%.

10.2.     Total nitrogen

Evaluated according to the procedure outlined in the appendix, nitrogen content should be between 16.8 and 17.8% on dry matter.

10.3.     Preparation of test trials solution

Dissolve 5 g of lysozyme in 100 ml of water.

10.4.     Heavy Metals

Add 2 ml of pH 3.5 solution (R) and 1.2 ml of reactive thioacetamide (R) to 10 ml of prepared test trial solution (10.3). There should be no precipitate. If a brown colour is produced, it should be less than the sample produced as indicated in the appendix. (Heavy metal content measured in lead should be under 10 mg/kg).

10.5.     Arsenic

Look for arsenic using the procedure in the appendix on 2 ml of test trial solution (10.3). (Arsenic content under 1 mg/kg).

10.6.     Lead

Measure out lead following the procedure in the Compendium on the test trial solution (10.3). (Lead content under 2 mg/kg.)

10.7.     Mercury

Measure out mercury following the procedure in the appendix on the test trial solution (10.3). (Mercury content under 1 mg/kg).

10.8.     Biological Contaminants

Evaluation carried out according to procedure in the appendix.

Total bacteria

under 103 CFU per g of preparation

Coliforms

maximum 10 per g of preparation

Escherichia coli

absence checked on 1 g sample

St. aureus

absence checked on 1 g sample

Salmonella

absence checked on 25 g sample

Yeasts

content limit 102 CFU per g of preparation

Total lactic bacteria

content limit : absence checked on a 10 g sample preparation

Acetic bacteria

content limit 102 CFU per g of preparation

Mould

content limit 102 CFU per g of preparation.

 

  1. Measuring turbidity of lysozyme activity in wine (Turbidimetric measuring)

11.1.     Principle

The analytical procedure was established by FIP (1997) with some modifications made by FORDRAS. The procedure is based on changes in turbidity changes in Micrococcus luteus ATCC 4678 induced by a lytic lysozyme activity.

Under normal test conditions, the above-mentioned changes are in proportion to the quantity of lysozyme.

11.2.     Substrate

Do not use an electromagnetic mixer when suspending between 40 – 60 mg of Micrococcus luteus ATCC 4698 (Boehringer) in powder form in phosphate solution M/15 pH 6.6 ( 0.1), when obtaining a homogeneous suspension and complete it with 100 ml with the same buffer. Use a hand mixer or an ultrasound bath.

The exact quantity of Micrococcus luteus to be taken depends on the spectrophotometer used.

Prepare a control sample with 5 ml of buffer and 5 ml of Micrococcus luteus and measure the absorbency with the aid of a 540 nm spectrophotometers compared to control sample of phosphate buffer. Absorbency should not be under 0.800.

If reading the measurement doesn’t correspond, the content of Micrococcus luteus must be adapted in the suspension and then measure the desired absorbency.

Note: With a sensitive spectrophotometer, the absorbency levels of above-mentioned solutions are 0.800 to 0.900. Equipment that are not as sensitive may give readings for the absorbency for this same suspension of 0.500 to 0.600.

In this case, we should not increase the amount of substrate to obtain initial absorbency rates of 0.800 to 0.900, because reproducing the measurement linearity are not very dependable.

11.3.     Preparation of standard solution

11.3.1.                      Dissolve exactly 50 mg of lysozyme chlorhydrate in water,and fill up to 100 ml in a graduated flask.

11.3.2.                      Dilute 5 ml of solution in 11.3.1 with water up to 50 ml.

11.3.3.                      Dilute 2 ml of this solution with a M/15 phosphate buffer up to 100 ml to obtain a 1 mg/1 of lysozyme (standard solution).

11.4.     A solution to analyse

Dilute the sample of wine with m/15 phosphate buffer to obtain the same concentration of standard solution (1 mg/l) in relation with the concentration of lysozyme.

11.5.     Procedure

Prepare the following solutions in 180 x 80 mm test tubes

Standard solution

Buffer M/15

Lysozyme concentration

to analyse

2.0 ml 

3.0 ml

0.4 mg/l

2.8 ml 

2.2 ml

0.56 mg/l

4.0 ml

1.0 ml 

0.8 mg/l

It is recommended to repeat each dilution 3 times for the standard solution and for the solution to be tested.

Prepare two test tubes with 5 ml of buffer as a suspension control sample for Micrococcus luteus. Use the first control sample in the beginning and the second one at the end of the trial.

After exactly 30 seconds, add 5 ml of Micrococcus luteus suspension. This must be mixed mannually to avoid over spilling. Mix with a Vortex and keep the tubes in 37°C ( 5°C) water for exactly 12 minutes.

The final quantity of lysozyme in the tubes will be 0.2 – 0.28 – 0.4 mg/l.

After incubation, remove the tubes in the same order they were placed in, with an interval of 30 seconds.

Mix and take a reading of the absorbency with the 540 nm spectrophotometer for white wine and 740nm for the red wine against the control buffer.

Under normal circumstances, the test trial is acceptable when the difference between the absorbency rates for the control samples is under 5%.

11.6.     Calculation

Prepare a standard curve indicating the average values of absorbency obtained for each standard solution on the y-axis. On the x-axis put the concentrations of lysozyme on a logarithm scale.

Carry over the results obtained for the dilutions to be analysed.

Draw two straight lines: one between the points obtained from the standard solution and the other between the points of the solution to be analysed. The two lines must be parallel, if not the dose is incorrect.

Then draw a line parallel to the x-axis so that the two right lines are cut about halfway the extreme limit for dosing.

In the two intersection points, which correspond to two concentrations on the x-axis (Cst concentration of the standard curve and Cx concentration of the curve for the solution to be analysed). The activity is calculated as follows:

Where

  • Cst = concentration of the standard solution
  • Cx  = concentration of the solution to be analysed
  • D = dilution factor
  1. Determination of lysozyme in wine

(Determination by HPLC)

The lysozyme residue can be determined by HPLC according to the method described in the Compendium on International Analysis Methods of Wines and Musts.

  1. Preservation

Lysozyme must be stored at room temperature in a closed sealed container, away from humidity.

  1. Bibliography
  • FIP (1997), Pharmaceutical Enzymes, A. Lowers and S. Scharpe ed. 1997, vol.84 pages 375-379.

Yeast mannoproteins

YEAST EXTRACTS CONTAINING MANNOPROTEINS

OENO 26/2004;

OIV-OENO 674-2022

1.     OBJECT, ORIGIN AND FIELD OF APPLICATION

Mannoproteins are extracted from Saccharomyces cerevisiae yeast cell walls by physico-chemical of enzymatic methods.

Mannoproteins are different structures depending on their molecular weight, their degree and type of glycosylation, and their load size. Depending on their extraction mode, they have different tartaric and/or protein stabilisation of wine.

2.     LABELLING

The label must indicate the field of application (tartaric and/or protein stabilisation of wine), security and storage conditions in addition to the date of expiry.

For solution preparations, the concentration of mannoproteins, the content of sulphur dioxide must likewise be indicated.

3.     CHARACTERISATION

            - Mannoproteins are found in powder form, usually microgranulated, white or beige in colour, odorless, or in a colloidal solution , yellow in colour, translucid.

3.2 - Mannoproteins are water soluble and insoluble in ethanol. In solution form, they precipate when 1 volume of ethanol is added.

Their water solubility is determined by comparing the total dry matter (DM) with the insoluble DM that remains after a hot wash, according to the method described in Annex 2. The percentage of insoluble DM should be less than or equal to 1% ± 0.5.

 

TRIALS

 

 

4.1      Loss through desiccation

 

            Powder mannoprotein:

Put 5 g of mannoproteins in a 70 mm diameter silica capsule. Place in 100-105 °C drying chamber for 5 hours. Weight loss must not be more than 15%.

            Mannoproteins in solution:

Put 10 g of mannoproteins in a 70 mm diameter silica capsule. Put over 100 °C water bath for 4 hours in a 100-105 °C drying chamber for  3 heures.

The quantity of dry residue must be at least 10%.

The limits set below are related to dry products.

 

  1.       Ashes

Incinerate dry residue at 550-600 °C. Ash content must not be more than 8%.

  1.                         Preparation of solution for trials

Prepare a 10 g/l mannoprotein solution in water.

In the case of mannoprotein solution, weigh amount corresponding to 5 g of dry residue, evaporate until almost dry and dissolve again to 10 g/l in water.

  1.                         Heavy metals

Determine iron on the solution prepared for trials (4.3) according to the method described in Chapter II of the International Oenological Codex

The content expressed in lead must be less than 30 mg/kg.

  1.                         Lead

Determine lead on the solution prepared for trials (4.3) according to the method described in Chapter II of the International Oenological Codex

The content expressed in lead must be less than 5 mg/kg.

 

  1.                         Mercury

Determine mercury on the solution prepared for trials (4.3) according to the method described in Chapter II of the International Oenological Codex without evaporating the solution.

The content of mercury must be less than 0.15 mg/kg.

 

  1.                         Arsenic

Determine arsenic according to the method described in Chapter II of the International Oenological Codex on a solution for trials (4.3) 

The content of arsenic must be less than 1 mg/kg.

 

  1.                         Cadmium

Determine cadium according to the method described in Chapter II of the International Oenological Codex on a solution for trials (4.3) 

The content of cadium must be less than 0.5 mg/kg.

 

  1.                         Total nitrogen

Introduce 5 g of mannoproteins in a 300 ml mineralisation flask with 15 ml of concentrated sulphuric acid (R) and 2 g of mineralisation catalyser (R). Continue the determination as indicated in Chapter II of the International Oenological Codex.

In the case of mannoprotein solution, weigh an amount corresponding to 5 g of dry residue, evaporate until almost dry then proceed as in the above.

The content of nitrogen must be between 5 and 75 g/kg

  1.                    Microbiological analysis

 

  1.            Total aerobic mesophile flora

Proceed with counting according to method described in Chapter II of the International Oenological Codex.

Not more than 10 000 total aerobic mesophile germs in 1 g.

  1.            Coliforms

Proceed with counting according to method described in Chapter II of the International Oenological Codex.

Not more than 10 CFU/g of preparation.

  1.  Staphylococcus aureus

Proceed with counting according to method described in Chapter II of the International Oenological Codex.

Absence checked for Staphylococcus aureus on a 1 g sample.

  1.            Salmonella

Proceed with counting according to method described in Chapter II of the International Oenological Codex.

Absence checked for salmonella on a 25 g sample

 

  1.            Escherichia coli

Proceed with counting according to method described in Chapter II of the International Oenological Codex.

Absence checked for Escherichia coli on a 25 g sample.

  1.            Lactic bacteria

Proceed with counting according to method described in Chapter II of the International Oenological Codex.

Not more than 104 CFU/g of perparation.

  1.            Mould

Proceed with counting according to method described in Chapter II of the International Oenological Codex.

Not more than 50 CFU/g of preparation.

  1.            Yeasts

Proceed with counting according to method described in Chapter II of the International Oenological Codex.

Not more than 102 CFU/g of preparation.

 

  1.                    Polysaccharides

 

  1.   Principle:

Measure colour intensity using hot phenol solution in a sulfuric medium.

  1.   Products:

4.11.2.1   15 mg/l mannoprotein solution

Dissolve 150 mg of mannoproteins in 100 ml of distilled water, then dilute this solution 1/100 with distilled water.

4.11.2.2   50 g/l phenol solution

Dissolve 5 g of pure phenol in 100 ml of distilled water.

  1.   Protocol:

200 µl of phenol (4.11.2.2) then 1 ml of pure sulphuric acid (R) are added to 200 µl of solution to be determined (4.11.2.1). After immediately mixing, the tubes are heated at 100°C in a bath water for 5 minutes and then cooled to 0 °C.

After reaching room temperature, absorbance is measured at 490 nm. 100 mg/l mannose solution is the reference solution.

(Content of polysaccharides expressed in equivalent of mannose above 600 g/kg)

  1.        Centesimal composition of glucidic monomers

 

4.12.1 Principle:

Enzymatic determination of glucose and mannose after acid hydrolysis.

The determination of mannose is carried out following the determination of fructose and the addition of  phosphomannose isomerase (PMI).

4.12.2 Products:

 4.12.2.1      Mannoprotein solution 5 g/l

 Dissolve 500 mg of mannoproteins in 100 ml of distilled water.

 4.12.2.2 Sulphuric acid solution 5 M

 Place 28 ml of sulphuric acid in 100 ml of distilled water.

 4.12.2.3 Potassium hydroxide solution 10 M

 Dissolve 46 g of potassium hydroxide in 100 ml of distilled water.

 4.12.2.4 Phosphomannose isomerase 616 U/ml.

4.12.3 Protocol:

Place 100 µl of solution to be determined (4.12.2.1) in airtight sealed tubes and add 1 ml of sulphuric acid (4.12.2.2). After mixing, the tubes are heated at 100 °C in a water bath for 30 minutes and then cooled to 0 °C. After room temperature is reached, 1 ml of potassium hydroxide is added to neutralise the medium.

The detrmination of glucose and mannose can be carried out according to the method described in the compendium. Mannoproteins must contain at least 70% of mannose compared to total polysaccharides determined in 4.11.

  1.      Mannoprotein efficency test with regards to tartaric precipitation
    1.   Principle:

Determination of dose of mannoproteins to delay cristallisation of potassium hydrogenotartrate in a hyrdoalcoholic solution.

4.13.2 Produits:

Crysalised tartaric Ac: PM = 150.05

Ethanol at 95% volume

Potassium chloride: PM= 74,5

Potassium hydrogenotartrate: PM= 188

  1.   Protocol:

4.13.3.1 Mannoprotein solution 10 g/l

Dissolve 1 g of mannoproteins in 100 ml of distilled water.

4.13.3.2 Hydro-alcoholic matrix

In a 1 liter volumetric flask half filled with distilled water dissolve:

-         Tartaric acid:      2.1 g

-         Potassium chloride:     1.1 g

-         Ethanol at 95 % volume:    110 ml

Homogenise and fill up with distilled water.

  1.   Test:

Place increasing quantities of mannoprotein solution (4.13.3.1) in a 100ml volumetric flask 0 – 1 – 2 – 3 - 4 ml and the volume is brought up to 100 ml with hydro-alcoholic matrix (4.13.3.2). These quantities correspond to final quantities of  0 – 100 – 200 – 300 - 400 mg/l of mannoproteins.

Add 100 mg potassium hydrogenotartrate in each flask.

Heat at 40 °C in a water bath for 1 hour until the complete solubilization of potassium hydrogenotartrate.

Stack the flasks in a refrigerator at 4 °C.

Observation after 48 hours:

The reference flask containing 0 ml of mannoprotein solution (4.13.3.1)

Presents potssium hydrogenotartrate crystals.

The absence of crystals in flasks containing mannoproteins aids in appraising the effectiveness. In all cases, crystals must be absent in a solution containing 400 mg/l of mannoproteins.

  1.         Mannoprotein efficiency test regarding protein casses
    1.   Principle

Determination of mannoprotein dose needed to improve protein stabilisation of wine.

  1.   Product:

Bovine serum albumen (Fraction V) (BSA)

  1.   Protocol:
  1.         10 g/l bovine serum albumen solution

Dissolve 2 g of bovine serum albumen in 200 ml of distilled water.

4.14.3.2 20 g/l mannoprotein solution

Dissolve 2 g of mannoproteins in 100 ml of distilled water.

4.14.4  Test

Placer 1 ml of BSA solution (4.14.3.1) in two 100 ml volumetric flasks and bring up to 100 ml in each flask with dry white wine which presents no cloudiness with heating (or stabilised if necessary with an adequate dose of bentonite treatment), and homogenize.

Adjust 0 and 1 ml of mannoprotein solution (4.14.3.2) and homogenize. These quantities correspond to 0 and 200 mg/l final doses of mannoproteins.

Filter reference and treated solutions through a membrance with a 0.45 µm pore diameter. Pour the filtered solutions in two 50 ml flasks. 

Place the 2 50 ml flasks and heat at 80 °C in a water bath for 30 minutes. Let cool to room temperature for 45 minutes, measure turbidity of reference and treated solution.

The decrease in turbidity between the reference sample and the treated sample must be at least 50%.

 

  1.                                 Dosage in wine

 

Principle

The dosage of mannoproteins in wine can be carried out after precipitating ethanol (5 volumes), acid hydrolysis from the precipitate and determination of released mannose according to the method listed in the annex.

 

 

5. STORAGE CONDITIONS

Solid mannoproteins must be stored away from humidity in a sealed pack in a temperate room.

Mannoproteins present in colloidal solutions ready to be used must be stored in a hermetically sealed container.

 

Annex 1

 

Determination of mannose using enzymatic method

Principle

 

Mannose is phosphorylated like glucose and fructose:


  Mannose + ATP   M6P + ADP

Following the determination of glucose and fructose, mannose–6-phosphate is transformed due to the action of phosphomannose isomerase (PMI) in fructose-6-phosphate.

           PMI


   M-6-P   F-6-P

Fructose-6-phosphate formed again is transformed as before in glucose-6-phosphate which is dosed.

Protocol

 

Place 5 ml of wine in a centrifuge tube and add 25 ml of 95% ethanol, after mixing the tubes are put in a 4°C refrigerator for 12 hours. The precipate formed is recuperated by a centrifuge, washed 2 times by 10 ml of 95% ethanol. The hydrolysis of the precipitate is carried out as in 4.12.

This determination does not enable the differentiation of mannoproteins added and natural mannoproteins.

Additional reagent regarding the method of the Compendium of International Methods of Analysis of Wines and Musts

 

Solution 6: phosphomannose isomerase (616 U/ml).

the suspension is used without diluting.

Determination

After measuring A3 following the methods of the Compendium of Methods of Analysis of Wines and Musts, add                                                        

Reference  Determination

Solution 6    0.02 ml  0.02 ml

Mix; carry out the determination after 30 min; monitor the end of the reaction after 2 min. (A4)

Determine the absorbances differences:

A4 – A3 corresponding to mannose for the reference and the determination

Subtract the aborbance difference for the reference (AT) and for the determination (AD ) and establish: AM= AD - AT              for mannose.

Results

For mannose: Cg/l = 0.423x AM  is obtained . 

Remark: If the measurements were carried out with wave lengths 334 or 365 nm, we obtain:

For a 334 nm measurement:

For mannose: Cg/l = 0.430x AM

365 nm measurement

For mannose: Cg/l = 0.783x AM

 

Annex 2

 

DETERMINATION OF THE PERCENTAGE OF INSOLUBLE DRY MATTER

1 – PRINCIPLE

The analysis consists of comparing the total dry matter (DM) of the yeast mannoprotein preparation with the insoluble DM that remains after a hot wash.

2 – MATERIAL AND REAGENTS

2-1 4200 rpm (6000g) Centrifuge and accessories
2-2 Scales with 0.1 mg precision
2-3 Oven at 105 °C +/- 1 °C

3 – PROCEDURE

Obtaining the insoluble part of the yeast mannoprotein preparation
- Place approx. 10 g of yeast mannoprotein preparation, previously placed in an oven at 105 °C until constant weight, in a tared centrifuge bucket. Note the exact weight, which will be referred to as M1.
- Suspend in hot water (70-80 °C).
- Stir.
- Centrifuge for 10 min at 4200 rpm (6000g).
- Discard the supernatant, stir again into hot water and centrifuge for 10 min at 4200 rpm.
- Carry out the procedure a third time.
- Place the tared centrifuge bucket containing the centrifugation pellet in an oven at 105 °C until constant weight. Note the weight. M2 is the weight of the residue of yeast mannoproteins preparation that make up the insoluble DM.

4 – CALCULATIONS

Insoluble dry matter percentage (Insoluble DM %) = (M2/M1) x 100

Electrodialysis membranes

COEI-1-MEMELE Electrodialysis membranes

  1. Objective, Origin and Scope of Application

An electrodialysis membrane is a thin, dense, insoluble wall composed of a polymer material that is permeable to ions.  When placed between two solutions, it allows the selective transfer of ions from one solution to the other when acted upon by an electric field.

The membrane pair consists of a cationic membrane and an anionic membrane.

The cationic membrane is a polymer which allows the preferred flow of cations, in particular the K+ and Ca++ cations.

The anionic membrane is a polymer which allows the preferred flow of anions, in particular tartrate anions.

Electrodialysis membranes are used to stabilize wine in the event of tartaric precipitation.

  1. Composition

The cation-exchange membrane that can be used is a styrene-divinylbenzene copolymer which carries sulfonic functional groups.

The anion-exchange membrane that can be used is either:

A styrene-divinylbenzene copolymer which carries quaternary ammonium functional groups, or A quaternary ammonium-divinylbenzene copolymer.

Electrodialysis membranes used for tartaric stabilization in wine should meet the following requirements:

2.1.     They should be manufactured in accordance with the good manufacturing practices for the substances enumerated in :

2.1.1.  Annex 1 pertaining to materials placed in contact with foodstuffs

2.1.2.  Annex 2 and Annex 3 pertaining to ion-exchange resins used in processing foodstuffs

2.2.     They should be prepared to serve their intended function, in accordance with the instructions of the manufacturer or supplier.

2.3.     They should not release any substance in a quantity which poses a human health threat or which alters the taste or odor of foodstuffs.

2.4.     In use, there should be no interaction between the constituents of the membrane and those of the wine that could form new compounds in the product that could produce toxicological consequences.

The stability of new electrodialysis membranes shall be established using a simulator which reproduces the physicochemical properties of wine, in order to study the migration of certain substances given off by the electrodialysis membrane.

The proposed experimental method is as follows:

Composition of the simulator:

This is an hydro-alcoholic solution with the pH and conductivity of wine. It is composed of

the following:

Absolute ethanol

11 liters

Potassium hydrogen tartrate

380 g

Potassium chloride

60 g

Concentrated sulfuric acid

5 ml

Distilled water

quantity sufficient for 100 liters

This solution is used to test migration in a closed circuit on a live electrodialysis stack (1 volt/cell) in a proportion of 50 liters/m2 of anionic and cationic membranes until the solution is 50% demineralized.  The effluent circuit is activated by a 5 g/l potassium chloride solution.

The migrating substances tested for in the simulator and in the electrodialysis effluent.

The organic molecules forming a constituent of membrane and which can migrate into the treated solution will be quantitatively analyzed.

A specific determination for each of these constituents will be carried out an approved laboratory. The content in the simulator must be less than the total, for all compunds analyzed at 50 μg/l.

Generally, the rules governing materials used in contact with foodstuffs shall also apply to these membranes.

  1. Limits on use

The membrane pair used for tartaric wine-stabilizationprocessing using electrodialysis is specified in such a way that:

  • the pH reduction in the wine is no greater than 0.3 pH units;
  • volatile acid reduction is less than 0.12 g/l (2 meq. expressed in acetic acid);
  • electrodialysis-based processing does not affect the non-ionic constituents of the wine, in particular the polyphenols and polysaccharides;
  • the diffusion of small molecules such as ethanol is reduced and does not lead to a reduction of alcohometric content greater than 0.1%.
  1. Conditions of use

These membranes should be stored and cleaned using accepted techniques and substances whose use is authorized for the preparation of foodstuffs.

Annex 1

List of monomers and other starting substances that can be used in the manufacture of plastic materials and devices designed to be placed in contact with foodstuffs, products, and beverages.

List of approved monomers and other starting substances

PM/REF No.

Case No.

Name

Restrictions

(1)

(2)

(3)

(4)

10030

000514-10-3

Abietic acid

 

10060

000075-07-0

Acetaldehyde

 

10090

000064-19-7

Acetic acid

 

10120

000108-05-4

Vinyl acetate

SML = 12 mg/kg

10150

000108-24-7

Acetic anhydride

 

10210

000074-86-2

Acetylene

 

10630

000079-06-1

Acrylamide

SML = ND (DL = 0.01 mg/kg

10660

015214-89-8

2-acrylamido-2-methylpropane-sulfonic  acid

SML = 0/05 mg/kg

10690

000079-10-7

Acrylic acid

 

10750

002495-35-4

Benzyl acrylate

 

10780

000141-32-2

n-butyl acrylate

 

10810

002998-08-5

Sec-butyl acrylate

 

10840

001663-39-4

Tert-butyl acrylate

 

11470

000140-88-5

Ethyl acrylate

 
 

000818-61-1

Hydroxyethyl acryltae

See « Ethylene glycol monoacrylate »

11590

00106-63-8

Isobutyl acrylate

 

11680

00689-12-3

Isopropyl acrylate

 

11710

000096-33-3

Methyl acrylate

 

11830

000818-61-1

Ethylene glycol monoacrylate

 

11890

002499-59-4

n-octyl acrylate

 

11980

000925-60-0

Propyl acrylate

 

PM/REF N°

Case N°

Name

Restrictions

12100

000107-13-1

Acrylonitrile

LMS = ND (LD = 0,020 mg/kg)

(including analylic tolerance)

12310

 

Albumin

 

12340

 

Albumin coagulated by formaldehyde

 

12375

 

Saturate, linear, primary monhydric alcohols (C4-C22)

 

12670

002855-13-2

1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane

SML = 6 mg/kg

12788

002432-99-7

11-aminoundecanoic acid

SML = 5 mg/kg

12789

007664-41-7

Ammonia

 

12820

00123-99-9

Azelaic acid

 

12970

004196-95-6

Azelaic anhydride

 

13000

001477-55-0

1,3-benzene dimethanamine

SML = 0.05 mg/kg

13090

000065-85-0

Benzoic acid

 

13150

000100-51-6

Benzylic acid

 
 

000111-46-6

Bis(2-hydroxyehtyl)ether

See Diethylene glycol

 

000077-99-6

2,2-bis(hydroxymethyl)-1-butanol

See 1,1,1-trimethylolpropane

13390

000105-08-8

1,4-bis(hydroxymethyl) cyclohexane)

 

13480

000080-05-7

2,2-bis(4-hydroxyphenyl) propane

SML = 3 mg/kg

13510

001675-54-3

Bis(2,3-epoxypropylic) ether of 2,2-bis(hydroxyphenyl) propane

MQ = 1 mg/kg PF or SML = non-detectable (DL = 0.020 mg/kg, including analytic tolerance)

 

000110-98-5

Bis(hydroxypropylic) ether

See Dipropylene glycol

 

005124-30-1

Bis(4-isocyananato-cyclohexyl) methane

See 4,4-Diisocyanate dedicyclohexylmethane

13530

038103-06-9

Bis(phthalic anhydride) of 2,2 bis(4-hydroxyphenyl) propane

SML = 0.05 mg/kg

13600

047465-97-4

3,3-bis(3-methyl-4-hydroxyphenyl)-2-indolinone

SML = 1.8 mg/kg

 

000080-05-7

Bisphenol A

See 2,2-bis(4-hydroxyphenyl) propane

 

001675-54-3

Bis(2,3-expoypropylic)ether of bisphenol A

See Bis(2,3-epoxypropylic)ether of 2,2-bis(4-hydroxyphenyl) propane

13614

038103-06-9

Bis (phthalic anyhydride)of bisphenol

See 13530

PM/REF N°

Case N°

Name

Restrictions

13630

000106-99-0

Butadiene

MQ =  1 mg/kg of PF or SML = non-detectable (DL = 0.02 mg/kg, including analytic tolerance)

3690

000107-88-0

1,3-butanediol

 

13840

000071-36-3

1-butanol

 

13870

000106-98-9

1-butene

 

13900

000107-01-7

2-butene

 

14110

000123-72-8

Butyraldehyde

 

14140

000107-92-6

Butyric acid

 

14170

000106-31-0

Butyric anhydride

 

14200

000105-60-2

Caprolactam

SML(T) = 15 mg/kg

14230

002123-24-2

Caprolactam, sodium salt

SML(T) = 15 mg/kg (expressed in terms of caprolactam)

14320

0001207-2

Caprylic acid

 

14350

00630-08-0

Carbon monoxide

 

14380

000075-44-5

Carbonyl chloride

MQ = 1 mg/kg in FP

14411

008001-79-4

Castor oil

 

14500

009004-34-6

Cellulose

 

14530

007782-50-5

Chlorine

 
 

000106-89-8

1-chloro-2,3-epoxy propane

See Epichlorhydrin

14680

000077-92-9

Citric acid

 

14710

000108-39-4

m-cresol

 

14740

000095-48-7

o-cresol

 

14770

00106-44-5

p-cresol

 
 

00105-08-8

1,4-cyclohexanedi-

methanol

See 1,4-bis(hydroxymethyl) cyclohexane

14950

003173-53-3

Cyclohexyl isocyanate

MQ(T) = 1 mg/kg in FP (expressed as NCO)

15070

001647-16-1

1,9-decadiene

SML = 0.05 mg/kg

15095

000334-48-5

Decanoic acid

 

15100

000112-30-1

1-decanol

 

PM/REF N°

Case N°

Name

Restrictions

 

000107-15-3

1,2-diaminoethane

See Ethylenediamine

 

000124-09-4

1,6-diaminohexane

See Hexamethylene- diamine

15250

000110-61-1

1,4-diaminobutane

 

15565

0000106-46-7

1,4-dichlorobenzene

SML == 12 mg/kg

15700

005124-30-1

Icyclohexylmethane-4,4’- diisocyanate

MQ(T) – 1 mg/kg in FP (expressed as NCO)

15760

000111-46-6

Diethylene glycol

SML(T) = 30 mg/kl alone or with ethylene glycol

15790

000111-46-6

Diethylene triamine

SML = 5 mg/kg

15820

000345-92-6

4,4’-difluorobenzo-phenone

SML = 0.05 mg/kg

15880

000120-80-9

1,2-dihydroxybenzene

SML = 6 mg/kg

15910

000108-46-3

1,3-dihydroxybenzene

SML = 2.4 mg/kg

15940

000123-31-9

1,4-dihydroxybenzene

SML = 0.6 mg/kg

15970

000611-99-4

4,4’-dihydroxybenzo-phenone

SML = 6 mg/kg

16000

000092-88-6

4,4’-dihydroxydiphenyl

SML = 6 mg/kg

16150

000108-01-0

Dimethylaminoethanol

SML = 18 mg/kg

16240

000091-97-4

3,3’-dimethylbiphenyl-4,4’-diisocyanate

MQ(T) = 1 mg/kg in FP (expressed as NCO)

16480

000126-58-9

Dipentaerythritol

 

16570

004128-73-8

4,4’-diisocyanate of diphenyl ether

MQ(T) = 1 mg/kg in FP (expressed as NCO)

16600

005873-54-1

Diphenylmethane-2,4’-diisocyanate

MQ(T) = 1 mg/kg in FP (expressed as NCO)

16630

000101-68-8

Diphenylmethane-4,4’-diisocyante

MQ(T) = 1 mg/kg in FP

(expressed as NCO)

16660

000110-98-5

Diproylene glycol

 

16750

000106-89-8

Epichlorhydrin

MQ = 1 mg/kg in FP

16780

000064-17-5

Ethanol

 

16950

000074-85-1

Ethylene

 

16960

000107-15-3

Ethylenediamine

SML = 12 mg/kg

16990

000107-21-1

Ethylenje glycol

SML(T) = 30 mg/kg alone or with diethylene glycol

PM/REF N°

Case N°

Name

Restrictions

17005

000151-56-4

Ethyleneimine

SML = ND (DL = 01 mg/kg)

17020

000075-21-8

Ethylene oxide

MQ = 1 mg/kg in FP

17050

000104-76-7

2-ethyl-1-hexanol

SML = 30 mg/kg

17160

000097-53-0

Eugenol

SML= 0.1 mg/kg

17170

061788-47-4

Coconut fatty acids

 

17200

068308-53-2

Fatty acids of soybean oil

 

17230

061790-12-3

Fatty acids of tall oil

 

17260

000050-00-0

Formaldehyde

SML = 15 mg/kg

17290

000110-17-8

Fumaric acid

 

17530

000050-99-7

Glucose

 

18010

000110-94-1

Glutaric acid

 

18070

000108-55-4

Glutaric anhydride

 

18100

000056-81-5

Glycerol

 

18250

000115-28-6

Hexachloroendo-methyl-Enetetrahy-drophthalic acid

SML = ND (DL = 0.01 mg/kg)

18280

00115-27-5

Hexachloroendome-thyl Enetetrahydro-phthalic anhydride

SML = ND (DL = 0.01 mg/kg)

18310

036653-82-4

1-hexadecanol

 

18430

00116-15-4

Hexafluoropropylene

SML = ND (DL = 0.01 mg/kg)

18460

000124-09-4

Hexamethylenediamine

SML = 2.4 mg/kg

18640

000822-06-0

Hexamethylene diisocyanate

MQ(T) = 1 mg/kg in FP (expressed as NCO)

18670

000100-97-0

Hexamehtylene tetramine

SML(T) = 15 mg/kg (expressed as formaldehyde)

 

00123-31-9

Hydroquinone

See 1,4-dihydroxybenzene

18880

000099-96-7

p-hydroxybenzoic acid

 

19000

000115-11-7

Isobutene

 

19210

001459-93-4

Dimethyl isophthalate

SML = 0.05 mg/kg

19270

000097-65-4

Itaconic acid

 

19460

000050-21-5

Lactic acid

 

PM/REF N°

Case N°

Name

Restrictions

19470

000143-07-7

Lauric acid

 

19480

002146-71-6

Vinyl laurate

 

19510

011132-73-3

Lignocellulose

 

19540

000110-16-7

Maleic acid

SML(T) 30 mg/kg

19960

00108-31-6

Maleic anhydride

SML(T) = 30 mg/kg (expressed as maleic acid)

 

000108-31-6

Melamine

See 2,4,6-triamino-1,3,5-triazine

20020

000079-41-4

Methacrylic acid

 

20080

002495-37-6

Benzyl methacrylate

 

20110

000097-88-1

Butyl methacrylate

 

20140

002998-18-7

sec-butyl methacrylate

 

20890

000097-63-2

Ethyl methacrylate

 

21010

000097-86-9

Isobutyl methacrylate

 

21100

004655-34-9

Isopropyl methacrylate

 

21130

000080-62-6

Methyl methacrylate

 

21190

000868-77-9

Ethylene glycol monomethacrylate

 

21280

002177-70-0

Phenyl methacrylate

 

21340

000760-93-0

Propyl methacrylate

 

21460

000760-93-0

Methacrylic anhydride

 

21490

000126-98-7

Methacrylonitrile

SML = not detectable (DL = 0.020 mg/kg, including analytic tolerance)

21550

000067-56-1

Methanol

 

21940

000924-42-5

N-methylolacrylamide

SML = ND (DL = 0.0 mg/kg)

22150

000691-37-2

4-methyl-pentene

SML = 0.02 mg/kg

22350

000544-63-8

Myristic acid

 

22390

000840-65-3

2,6-dimethyl naphthalene-dicarboxylate

SML = 0.05 mg/kg

22420

003173-72-6

1,5-naphthalene diisocyanate

MQ(T) 1 mg/kg in FP (expressed as NCO)

PM/REF N°

Case N°

Name

Restrictions

22450

009004-70-0

Nitrocellulose

 

22480

000143-08-8

1-nonanol

 

22570

000112-96-9

Octadecyl isocyanate

MQ(T) = 1 mg/kg in FP (expressed as NCO)

22600

000111-87-5

1-octanol

 

22660

000111-66-0

1-octene

SML = 15 mg/kg

22763

000112-80-1

Oleic acid

 

22780

000057-10-3

Palmitic acid

 

22840

000115-77-5

Pentaerythritol

 

22870

000071-41-0

1-pentanol

 

22960

000108-95-2

Phenol

 

23050

000108-45-2

1,3-phenylenediamine

MQ = 1 mg/kg in FP

 

000075-44-5

Phosgene

See Carbonyl chloride

23170

007664-38-2

Phosphoric acid

 
   

Phthalic acid

See Terephthalic acid

23200

000088-99-3

o-phthalic acid

 

23230

000131-17-9

Diallyl phthalate

SML = ND (DL = 0.01 mg/kg)

23380

000085-44-9

Phthalic anhydride

 

23470

000080-56-8

alpha-pinene

 

23500

000127-91-3

beta-pinene

 

23590

025322-68-3

Polyethylene glycol

 

23651

025322-69-4

Polypropylene glycol

 

23740

000057-55-6

1,2-propanediol

 

23800

000071-23-8

1-propanol

 

23830

000067-63-0

2-propanol

 

23860

000123-38-6

Propionaldehyde

 

23890

000079-09-4

Propionic acid

 

PM/REF N°

Case N°

Name

Restrictions

23950

000123-62-6

Propionic anhydride

 

23980

000115-07-1

Propylene

 

24010

000075-56-9

Propylene oxide

MQ = 1 mg/kg in FP

 

000120-80-9

Pyrocatechol

See 1,2-dihydroxybenzene

24057

000089-32-7

Pyromellitic anhydride

SML = 0.05 mg/kg (expressed as pyromellitic acid)

24070

073138-82-6

Resin acids

 
 

000108-46-3

Resorcinol

See 1,2-dihydroxybenzene

24100

008050-09-7

Rosin

 

24130

008050-09-7

Rosin gum

See Rosin

24160

008052-10-6

Tall oil resin

 

24190

009014-63-5

Wood resin

 

24250

009006-04-6

Natural rubber

 

24270

000069-72-7

Salicylic acid

 

24280

000111-20-6

Sebacic acid

 

24430

002561-88-8

Sebacic anhydride

 

24475

001313-82-2

Sodium sulfide

 

24490

000050-70-4

Sorbitol

 

24520

008001-22-7

Soybean oil

 

24540

009005-25-8

Food starch

 

24550

000057-11-4

Stearic acid

 

24610

000100-42-5

Styrene

 

24820

000110-15-6

Succinic acid

 

24850

000108-30-5

Succinic anhydride

 

24880

000057-50-1

Saccharose

 

24887

006362-79-4

5-sulfoisophthalic acid, monosodium salt

SML = 5 mg/kg

PM/REF N°

Case N°

Name

Restrictions

24888

003965-55-7

 5-dimethylsulfo- isophthalate, monosodium salt

SML = 0.05 mg/kg

24910

000100-21-0

Terephthalic acid

SML = 7.5 mg/kg

24940

000100-20-9

Terephthalic acid dichloride

SML(T) = 7.5 mg/kg (expressed as terephathalic acid)

24970

000120-61-6

Dimethyl terephthalatae

 

25090

000112-60-7

Tetraethylene glycol

 

25120

000116-14-3

Tetrafluoroethylene

SML = 0.05 mg/kg

25150

000109-99-9

Tetrahydrofuran

SML = 0.6 mg/kg

25180

000102-60-3

N,N,N’,N’-tetrakis(2-hydroxypropyl)-ethylene-diamine

 

25210

000584-84-9

Toluene-2,4-diisocyanate

MQ(T) = 1 mg/kg in FP (expressed as nCO)

25240

000091-08-7

Toluene-2,6-diisocyanate

MQ(T) = 1 mg/kg in FP (expressed as nCO)

25270

026747-90-0

Toluene-2,4-diisocyanate, dimer

MQ(T) = 1 mg/kg in FP (expressed as nCO)

25360

 

2,3-epoxy trialkyl(C5-C15) acetate

SML = 6 mg/kg

25420

000108-78-1

2,4,6-triamino-1,3,5-triazine

SML = 30 mg/kg

25510

000112-27-6

Triethylene glycol

 

25600

000077-99-6

1,1,1-trimethylolpropane

SML = 6 mg/kg

25910

024800-44-0

Tripropylene glycol

 

25960

000057-13-6

Urea

 

26050

000075-01-4

Vinyl chloride

See Council Directive 78/142/EEC

26110

000075-35-4

Vinylidene chloride

MQ = 5 mg/kg in FP or SML = ND (DL = 0.05 mg/kg)

26140

000075-38-7

Vinylidene fluoride

SML = 5 mg/kg

A number of abbreviations or notations are given in Column 4. Their meaning is listed below:

  • DL =Detection limit of the analytical method.
  • FP = Finished material or product
  • NCO = isocyanate group
  • ND = not detectable.

For the purposes of the present directive, the expression «not detectable» means that the substance will not be detected by the approved analytical method, which is sensitive enough to detect it at the specified detection limit. If, however, a method of this kind does not currently exist, an analytical technique possessing performance characteristics suited to the specified limit may be used, while awaiting the development of an approved method.

  • MQ = maximum permitted quantity of the «residual» substance in the material or article.
  • MQ(T) = maximum permitted quantity of residual substance in the material or article, expressed as the total group or of the indicated substances(s).

For the purposes of this directive, «MQ(T)» means that the maximum permitted quantity of the «residual» substance in the material or article should be determined using an analytical method approved for the specified limit. If, however, a method of this kind does not currently exist, an analytical technique possessing performance characteristics suitable for determining the specified limit may be used, while awaiting the development of an approved method.

  • SML = specific migration limit in the food product or the simulated food, unless otherwise specified.

For the purposes of this directive, «SML» means that the specific migration of the substance should be determined using an analytical method approved for the specified limit. If, however, a method of this kind does not currently exist, an analytical technique possessing performance characteristics suitable for determining the specified limit may be used, while awaiting the development of an approved method.

  • SML(T) = specific migration limit in the food product or simulated food, expressed as the total

of the group or of the indicated substance(s).

For the purposes of this directive, «SML(T)» means that the specific migration of the substance should be determined using an analytical method approved for the specified limit. If, however, a method of this kind does not currently exist, an analytical technique possessing performance characteristics suitable for determining the specified limit may be used, while awaiting the development of an approved method.

Annex 2: List of substances used in the manufacture of adsorbant ion-exchange resins used to condition foodstuffs. (Resolution AP (97)1 EC)

List 1: Substances assessed by an international organization

Name

PM/REF

Case

Restrictions

Monomers and other

Starting substances

n-butyl acrylate

10780

00141-32-2

-

Ethyl acrylate

11470

00140-88-5

-

Methyl acrylate

11710

00096-33-3

-

Acrylonitrile

12100

00107-13-1

SML = ND

(DL = 0.02 mg/kg)

SML = 15 mg/kg

Formaldehyde

17260

00050-00-0

 

Methyl methacrylate

21130

00080-62-6

-

Methanol

21550

00067-56-1

-

Styrene

24610

00100-42-5

-

Chemical Modifiers

Carbonic acid, salts

42500

-

-

Hydrochloric acid

72640

07664-38-2

-

Silicic acid, salts 

85980

-

-

Sulfuric acid

91920

07664-93-9

-

Acetic anhydride

10150

00108-24-7

-

tert-butyl-4-hydroxyanisole (BHA)

40720

25013-16-5

SML=30 mg/kg

Diethylene triamine

15790

00111-40-0

SML= 5 mg/kg

Dimethylamine

49225

00124-40-3

SML=0.06 mg/kg

2-(dimethylamino)ethanol

49235

00108-01-0

SML=18 mg/kg

Formaldehyde

54880

00050-00-0

SML=15 mg/kg

Hexamethylenediamine

18460

00124-09-4

SML=2.4 mg/kg

Potassium hydroxide

81600

01310-58-3

-

Sodium hydroxide

86720

01310-73-2

-

Sodium nitrite

86920

07632-00-0

SML=0.6 mg/kg

Ethylene oxide

17020

00075-21-8

MQ=1 mg/kg in FP

2-propanol

81882

00067-63-0

-

Polymerization Additives

Akylsulfonic acids (C8-C22)

34230

-

SML=6 mg/kg

Linear, primary alkylsulfuric

34281

-

-

acids (C8-C22) having an even number

 of carbon atoms

Formic acid

55040

00064-18-6

-

Carboxymethylcellulose

42640

09000-11-7

-

Stannic chloride(IV)

93420

07646-78-8

-

Methylene chloride

66620

00075-09-2

SML=0.05 mg/kg

1,4-dihydroxybenzene

48620

00123-31-9

SML=0.6 mg/kg

Gelatin

55440

09000-70-8

-

Ammonium hydroxide

35600

01336-21-6

-

Magnesium hydroxide

64640

01309-42-8

-

Hydroxyethylcellulose

60560

09004-62-0

-

Hydroxethylmethylcellulose

60880

09032-42-4

-

Methanol

65960

00067-56-1

-

Methylcarboxymethylcellulose

66200

37206-01-2

-

Methyl isobutyl ketone

66725

00108-10-1

SML=5 mg/kg

Toluene

93540

00108-88-3

SML=1.2 mg/kg

Annex 3 Substances that may be used provisionally to manufacture ion-exchange resins.

List 2 Substances not fully evaluated by an international organization

Name

PM/REF

Case

Restrictions

Monomers and other starting substances

Ethylene glycol dimethacrylate

20440

00097-90-5

-

Divinylbenzene

16690

01321-74-0

-

Diallyl ether of 1,1,1-tri- methylolpropane

25645

00682-09-7

-

2,3-epoxypropyl methacrylate

20590

00106-91-2

-

2-methyl-1,3-butadiene

21640

00078-79-5

-

1,7-octadiene

22585

03710-30-3

-

1,1,1-trimethylolpropane trimethacrylate

25840

03290-92-4

-

Chemical Modifiers

N,N-dimethyl-1,3-diamino- propane

49380

00109-55-7

-

Triethylamine

95270

00121-44-8

-

Triethylene tetramine

25520

00112-24-3

-

Polymerization Additives

Polyvinyl alcohols

81280

09002-89-5

-

4-tert-butylcatechol

40640

00098-29-3

-

Diisobutyl ketone

49050

00108-83-8

-

Sodium hypochlorite

62110

07681-52-9

-

Isobutanol

62270

00078-83-1

-

4-methoxyphenol 

66030

00150-76-5

-

Methylene bis(sodium naphtha- lenesulfonate)

66600

26545-58-4

-

2-methyl-2-pentanol

66860

00108-11-2

-

Dibenzoylperoxide

46440

00094-36-0

-

Partially hydrolyzed vinyl polyacetate

81260

-

-

Substances not evaluated by an international organization

Name

PM/REF

Case

Restrictions

Monomers and other starting substances

Dimethoxymethane

-

00109-87-5

-

Diethylene glycol divinyl ether

-

00764-99-8

-

Ethyl vinyl benzene

-

28106-30-1

-

1,2,4-trivinyl cyclohexane

-

02855-27-8

-

Chemical Modifiers

Chlorosulfonic acid

-

07790-94-5

-

Monochloroacetic acid

-

00079-11-8

-

Phosphoric acid

-

13598-36-2

-

Bromine

-

07726-95-6

-

2-chloroethanol

-

00107-07-3

-

Methyl chloride

-

00074-87-3

-

1,2-dichloroethane

-

00107-07-3

-

1,2-dichloropropane

-

00078-87-5

-

3-(dimethylamino)propane

-

03179-63-3

-

Name

PM/REF

Case

Restrictions

Monomers and other starting substances

Methylic chloromethyl ether

-

00107-30-2

-

Nitrobenzene

-

00098-95-3

-

Potassium nitrite

-

07758-09-0

-

Phthalimide

-

0085-41-6

-

Sulfur trioxide

-

07446-11-9

-

Trimethylamine

-

00075-50-3

-

Polymerization additives

 

Lignosulfonic acid

63940

08062-15-5

-

Peracetic acid

-

00079-21-0

-

Polyacrylic acid

76460

09003-01-4

-

Poly(styrenesulfonic) acid

-

09080-79-9

-

Acrylamide/acrylic acid copolymer

-

09003-06-9

-

Ethoxylated, propoxylated tert-alkylamines (C12-C14)

-

68603-58-7

-

Maleic anhydride-styrene copolymer, ammonium salt

-

26022-09-3

-

Attapulgite

-

12174-11-7

-

Azobisisobutyronitrile

-

00078-67-1

-

1,1-bis(tert-butylperoxy)-3,3,5- trimethylcyclohexane

-

06731-36-8

-

n-Dodecyl mercaptan

-

25103-58-6

-

Poly(ethylene/propylene)glycol monobutyl ester

-

09038-95-3

-

Polyethylene glycol octylphenyl ether

78560

09002-93-1

 

Poly(ethylene-propylene/glycol ether with 1,1,1-tromethylol-propane

-

52624-57-4

-

tert-hexadecyl mercaptan

-

25360-09-2

-

Cumyl hydroperoxide

-

00080-15-9

-

Isododecane

62405

31807-55-3

-

Isooctane

-

26635-64-3

-

Mono- and dialkyl (C10-C18) Sulfonamides

-

-

-

Silver nitrate

-

07761-88-8

-

n-Octane

-

00111-65-9

-

tert-Butyl peracetate

-

00107-71-1

-

tert-Butyl perbenzoate

-

00614-45-9

-

bis(4-tert-butylcyclohexyte) percarbonate tert-

-

15520-11-3

-

Butyl per(2-ethyl-hexanoate)

-

03006-82-6

-

tert-Butyl peroctanoate

-

13467-82-8

-

Dilauroyl peroxide

-

00105-74-8

-

Poly(diallyldimethylammonium chloride

-

26062-79-3

-

Polyvinylpyrrolidone

81500

09003-39-8

-

Reverse osmosis membranes

COEI-1-MEMOSM Reverse osmosis membranes

  1. Objective, origin and scope of application

A reverse osmosis membrane is a membrane belonging to the group of semi-permeable thin-layer composites (known as TFC, or Thin Film Composites).

Reverse osmosis is a must-enrichment treatment. It entails the use of a membrane to remove pure water, thus increasing the concentration of sugars and other constituents in solution in grape musts.

  1. Principle underlying the procedure

This is a physical process for removing a portion of the water in a must using a semi-permeable membrane acted upon by a pressure gradient at ambient temperature and without changing or degrading its condition.

The equipment used consists essentially of a so-called « booster » pump which feeds a high-pressure pump (under 100 bars, for example) which allows osmotic pressure to be overcome, a membrane block and control apparatuses such as a flow meter, pressure indicator, pressure regulator, etc.

  1. Composition

All equipment used in this Prescriptions must be in compliance with the regulations concerning fittings which come into contact with foodstuffs (pipes, pumps, control apparatuses, joints, etc.) and in particular, the reverse osmosis membrane.

The substances which make up the membrane must be in compliance with the regulations in force.

These membranes ares prepared by in situ polymerization of a polymer on the surface of a porous substrate.  The substrate is typically an polysulfone ultrafilter. The thin layer serves as a discriminating membrane, while the porous substrate provides physical support.

As an example, the structural formula of the polyamide base is as follows:

  1. Implementation

During the manufacturing process, the membrane passes through a number of extraction baths containing hot water in order to eliminate traces of solvent and residual monomers.

In particular, under normal or unforeseen circumstances it cannot give off any constituents which could pose a threat to human health (with respect to the component most easily measured, i.e., sodium chloride, in particular, it should  exhibit a substance-retention rate greater than 99%). It must not cause an undesirable change of the composition of the grape must (or of a solution containing 170 g/l of sugar and 5 g/l of tartaric acid neutralized to a pH of 3.5 by potassium hydroxide), nor can it alter the organoleptic properties of the must.

  1. Membrane Regeneration

As regenerating agent, the operator can use inorganic products permitted under the regulations, provided that the operation ends by washing with water so as to completely remove the regenerating agent before adding the must.

  1. Limits

All equipment/materials in contact with food products must be in compliance with the standards in force.

There should be no perceptible change of the organoleptic properties of the processed must.

Any release of product or derivative constituting a constituent of the membrane must be less than 50 μg/l in its entirey, which is the recommended value, and it must comply with the regulatory limits governing the specific migration of the various materials constituents.

  1. Special restrictions

Membranes may be supplied only by approved suppliers or distributors.

Use of the membrane must be monitored and restricted by :

  • installing a time meter and a volumeter which are sealed at the permeate outlet,
  • the physical impossibility inhering in the process of increasing the concentration of the must beyond the established threshold.

Bipolar electrodialysis membranes

COEI-1-MEMBIP Bipolar electrodialysis membranes

  1. Object, origin and scope of application

A bipolar membrane is a thin, dense, insoluble wall composed of a polymer material functionalized by ionic groups. A bipolar membrane has an anionic face and a cationic face; it is equivalent to combining a cationic membrane and an anionic membrane into a single membrane. Cationic and anionic membranes are defined in the International Oenological Codex (Electrodialysis membranes, OENO 29/2000)

The membrane pair used in the bipolar electrodialysis acidification technique consists of a bipolar membrane and a cationic membrane. This arrangement, in the stack of an electrodialyser, only permits the extraction of cations.

The cationic membrane allows the preferred flow of cations, in particular potassium.

The function of the bipolar membrane is to maintain the acido-basic ionic balance of the system, following the extraction of a percentage of the potassium from the must or wine.

  1. Composition of the membranes

2.1.    Composition of the cation membrane

Cation membranes used in the acidification technique by bipolar membrane electrodialysis must comply with the prescriptions stated in the monograph concerning electrodialysis membranes (Resolution OENO 29/2000) in the International Oenological Codex.

2.2.    Composition of the bipolar membrane

The bipolar membrane suitable for use is a styrene-divinylbenzene copolymer, whose cationic face and anionic face comply with the composition of cationic and anionic membranes described in the International Oenological Codex (Electrodialysis membranes, OENO 29/2000)

2.3.    They should be manufactured in accordance with the good manufacturing practices for the substances listed in:

2.3.1.  Annex 1 of the monograph on electrodialysis membranes (Resolution OENO 29/2000) pertaining to materials placed in contact with foodstuffs.

2.3.2.  Annexes 2 and 3 of the monograph on electrodialysis membranes (Resolution OENO 29/2000) pertaining to ion-exchange resins used in processing foodstuffs.

2.4.    They should be prepared to serve their intended function, in accordance with the instructions provided by the manufacturer or supplier.

2.5.    They should not release any substance in a quantity which endangers human health or which degrades the taste or odour of foodstuffs.

2.6.    In use, there should be no interaction between the constituents of the membrane and those of the must or wine likely to form new compounds in the treated product that could have toxicological consequences.

  1. Limits on use

The diffusion of small molecules such as ethanol should be limited and should not result in a reduction in the alcoholic strength greater than 0.1% by volume.

  1. Conditions of use

The membranes shall be stored and cleaned using accepted techniques and substances whose use is authorised for the preparation of foodstuffs.

Ultrafiltration membranes

COEI-1-MEMULT Ultrafiltration membranes

  1. Object, origin and scope of application

 

Membranes belonging to the family of porous membranes, these can be organic or inorganic, and are generally anisotropic (asymmetric) or composite membranes; they may have a spiralled or "spiral-wound", flat sheet or "frame and plate", tubular or hollow fibre configuration.

Ultrafiltration is a physical separation process which is applied to the separation of particles ranging from 0.001 to 0.1 μm with retention of macromolecules and colloidal aggregates.

Ultrafiltration membranes are characterised by the retention of standard macromolecules with known molar masses.  The cut-off threshold (or MWCO for molecular weight cut-off) is defined as the molar mass of a macromolecule from the standard range that would be retained at 90 or 95%.

The active layer of the ultrafiltration membranes consists of organic or inorganic material that has a microporous structure with pore diameters of about one nanometre.

  1. Procedure principle

This is a physical filtration method allowing the particles and macromolecules in the must or wine to be retained using a semi-permeable membrane driven by a pressure gradient at ambient temperature.

The process is carried out as a tangential flow. The apparatus mainly consists of what is called a "booster" pump feeding a circulation pump between 2 and 10 bars, a membrane block and monitoring equipment, such as a flowmeter, pressure indicator and controller, etc.

  1. Composition

All the equipment used in the procedure conforms with regulations relating to equipment in contact with food (pipes, pumps, monitoring equipment, joints, etc.).

These membranes are usually prepared through in situ polymerisation of a polymer on the surface of a porous substrate. The thin layer serves as the discriminating membrane, while the porous substrate acts as the physical support.

Examples of the main organic polymers used may include cellulose acetate, polyacrylonitrile, polyamide, polysulfone, polyimide, etc.

Mineral membranes are usually the composite materials, since the support is different from the active layer. They only exist as flat or tubular membranes. For the supports, ceramics make up the majority of membranes, but porous carbon and metal oxides may also be used. Active layers are often comprised of aluminium oxide, zirconium dioxide or titanium dioxide (in the case of ceramics).

  1. Labelling

The main characteristics should be indicated on the label, particularly the batch number.

  1. Manufacture

Through a number of procedures, it is possible to obtain a whole range of pore sizes (from MFT to the dense membrane of RO).

The final characteristics (thickness, porosity, pore size, internal structure) of the membrane depend on a great number of parameters (choice of ternary solvent/polymer/non-solvent, composition of collodion, addition of porogenes, operating conditions - temperature, casting speed, diameter/thickness of the collodion, etc.)

For mineral membranes, the active layer is generally obtained by the sol-gel method, then laid on the solid support.  The final step is sintering (between 400 and 1200 °C) which is used to adjust the average diameter of the pores of the membrane from the grain size of the initial powder.

  1. Membrane cleaning

The user may use inorganic products authorised according to regulations, provided that the operation ends by rinsing with water so as to completely remove the cleaning product before adding the must or wine.

  1. Limits
  • All the equipment in contact with food products must comply with the standards in force.
  • There should be no noticeable change in the organoleptic characteristics of the must.

Any potential release of the product or derivative comprising the membrane must comply with the current specific migration standards for the various constituents of the equipment.

  1. Special restrictions

The membrane must meet the regulatory requirements for equipment in contact with food.

Nanofiltration membranes

COEI-1-NANMEM Nanofiltration membranes

  1. Object, origin and scope of application

Membranes belonging to the family of semi-permeable membranes, these can be homogenous or composite membranes and are generally organic; they may have a spiralled or "spiral-wound", flat sheet or "frame and plate", tubular or hollow fibre configuration.

Nanofiltration is a membrane technique under pressure that covers a separation scope between reverse osmosis and ultrafiltration, enabling the separation of molecules in solution at less than approximately 2 nm. Most of the membrane materials used in nanofiltration have surface charges that play a part in the separation of ionic species, thus the selective retention of multivalent ions compared with monovalent ions can be obtained.

Generally, the MWCO (Molecular Weight Cut Off) of separation for organic compounds varies from 150 to 500 g·mol-1 (150 to 500 daltons) to a maximum of 2000 g·mol-1 (2000 daltons).

The transfer selectivity of the solutes through the membrane is generally expressed by their retention rate (= [1- (final conc. / initial conc.)] x 100).

  1. Procedure principle

This is a physical method of removing a portion of the solvents (water and alcohol) and very low molecular weight compounds from the must or wine (close to the cut off) using a semi-permeable membrane driven by a pressure gradient at ambient temperature and without changing or altering its state.

The process is carried out as a tangential flow.

The apparatus may consist, for example, of a high pressure pump (e.g. from 2 to 8·104 Pa or 20 to 80 bars) used to overcome the osmotic pressure, a membrane block and monitoring equipment, such as a flowmeter, pressure indicator and controller, etc.

  1. Composition

All the equipment used in the procedure conforms with regulations relating to equipment in contact with food (pipes, pumps, monitoring equipment, joints, etc.).

These membranes are usually prepared through in situ polymerisation of a polymer on the surface of a porous substrate. The thin layer serves as the discriminating membrane, while the porous substrate acts as the physical support.

For example, the main organic polymers used may include cellulose acetate and polyamide, etc.

As an example, the structural formula of the polyamide base is as follows:

  1. Labelling

The main characteristics should be indicated on the label, particularly the batch number.

  1. Manufacture

Through a number of procedures, it is possible to obtain a whole range of pore sizes, from tangential microfiltration to the dense membrane of reverse osmosis.

The final characteristics (thickness, porosity, pore size, internal structure) of the membrane depend on a great number of parameters (choice of ternary solvent/polymer/non-solvent, composition of collodion, addition of porogenes, operating conditions - temperature, casting speed, diameter/thickness of the collodion, etc.)

  1. Membrane cleaning

The user may use inorganic products authorised according to regulations, provided that the operation ends by rinsing with water so as to completely remove the cleaning product before adding the must or wine.

  1. Limits

All the equipment in contact with food products must comply with the standards in force.

There should be no noticeable change in the organoleptic characteristics of the processed must or wine.

Any potential release of the product or derivative comprising the membrane must comply with the current specific migration standards for the various constituents of the equipment.

  1. Special restrictions

The membrane must meet the regulatory requirements for equipment in contact with food.

Metatartaric acid

COEI-1-METACI Metatartric acid

Ditartaric acid

Acidum ditartaricum

SIN N°. 353

  1. Objective, origin and scope of application

 

The name metatartaric acid applies to the product obtained by dehydrating L-tartaric acid at a temperature of 150-170 °C under atmospheric pressure or under a reduced pressure.

This product can retard tartaric precipitation in the bottle.

Its effectiveness in preventing tartaric precipitation is directly related to the rate of esterification

The quantity in which it is used in wines is restricted.

The primary constituents of the product are the ditartaric monoester and diester in variable proportions based on the combination of two molecules of tartaric acid with water loss, mixed with variable quantities of non-esterified tartaric acid, pyruvic acid and small quantities of poorly known polyester acids.

This product exists in crystalline masses or in powder form with a white or greater or lesser yellowish color. It has a faint odor of toast or caramel and is very deliquescent.

It is highly soluble in water and alcohol and rapidly hydrolyzed in aqueous solution at 100 °C, but much more slowly at cold temperatures.

  1. Labelling

The label should indicate the esterification rate and safety and storage conditions, as well as the optimal expiration date.

  1. Determination

3.1.    Place a sample of 1-10 mg of this substance in a test tube with 2 ml of concentrated sulfuric acid (R) and 2 drops of sulforesorcinic reagent (R).  When heated to 150 °C, an intense violet coloration appears.

3.2.    Place 2.50 ml of 10 pp 100 (m/v) tartaric acid in 20 alcohol by volume in a 100 ml cylindrical flask. Add 10 mg of metatartaric acid (0.5 ml of 2% solution), 40 ml of water and 1 ml of 25 pp 100 calcium acetate solution (R).  Stir.  A weak, amorphous precipitate remaining in suspension will appear for certain samples having a high ester number when they contain a small quantity of poorly known polyesters.  No crystallized precipitate should form within 24 hours, whereas a mixture of the same reagents without metatartaric acid yields a crystallized precipitate within several minutes.

  1. Tests

4.1.    Appearance

A 10 pp 100 aqueous solution of metatartaric acid should be clear and almost colorless or slightly amber in color.

4.2.    Preparation of the Test Solution

Prepare a metatartaric acid solution in a concentration of 20 g/l in water.

4.3.    Quantitative Analysis

Place 50 ml of very recently prepared 2 pp 100 solution (1 g of metatartaric acid) in a 250 ml conical flask.  Add 3 drops of bromothymol blue solution (R) in a concentration of 4 g/l and 1 M sodium hydroxide solution until the indicator turns bluish-green.  Let n be the number of ml used.

Add 20 ml of 1M sodium hydroxide.  Insert the stopper and let sit for 2 hours at ambient temperature.  Titrate the excess alkaline solution using 0.5M sulfuric acid.  Let n' be the number of millimeters used: 1 ml of 1M sodium hydroxide corresponds to 0.075 g of tartaric acid.

Content (pp 100 of total free and esterified acid) of the tested product:

Ester content pp 100 of total acid functions:

The wine-making product must contain at least 105 pp 100 total tartaric acid after hydrolysis and 32 pp 100 esterified acid.

4.4.    Heavy Metals

Using the thioacetamide technique described in the annex, determine heavy metals content in the test solution prepared in accordance with Par. 4.2 (when expressed for lead, the heavy metals content must be lower then 10 mg/kg).

4.5.    Lead

Using the technique described in the Compendium, quantify the proportion of lead in the test solution (Par. 4.2). (Lead content should be less than 5 mg/kg).

4.6.    Mercury

Using the technique described in the annex, determine the proportion of mercury in the test solution prepared in accordance with Par. 4.2 (content must be lower then 1 mg/kg).

4.7.    Arsenic

Using the technique described in the annex, determine arsenic content in the test solution prepared in accordance with Par. 4.2 (content must be lower then 3 mg/kg).

  1. Storage

Metatartaric acid should be stored in hermetically sealed containers away from air and moisture.

Egg (albumin of)

COEI-1-OEUALB Egg (Albumin of)

Ovalbumin

Albumen ovi

  1. Objective, origin and scope of application

The albumin of an egg is obtained by desiccating fresh egg whites.  It is found in the form of a fine, white, very light powder which is not completely soluble in water, but is soluble in certain alkaline solutions.

Fining agent for clarifying wines.

Egg albumin is sold in powder or spray form, or it may be used directly in the form of albumin from fresh or sterilized eggs.

Egg albumin is precipitated by tannin.  Typically, 2 g of pure tannin are required to precipitate 1 g of egg albumin.

  1. Labelling

The label should indicate the storage, hygienic, and safety conditions, as well as the optimal use-by date.

 

  1. Determination of identifying properties

 

3.1.    Preparation of a 10g/l Solution and Properties

3.1.1.  Prepare an egg albumin slution by weakening the power with a very small quantity of water, so as to give a homogenous paste. Next, weaken gradually in order to obtain a solution having a concentration of 10g/l. This solution must have no unpleasant taste or odor.

This solution will have a pH of between 6.5 and 7. It will foam abundantly when shaken and will coagulate when heated in the presence of neutral salts.

Ovalbumin precipitate from its solutions by ammonium sulfate dissolved at saturation, by nitric acid and by alcohol

3.1.2.  The pH of albumin from fresh eggs ranges between 8.5 and 9.5.

3.2.    Disclosure of the Presence of Gum, Dextrin, and Gelatin

To 10 ml of a solution (concentration: 10 g/l) (Par. 3.1), add 0.5 ml concentrated nitric acid (R). Heat to 50-60o. A precipitate will form. Allow to cool, then filter. The filtrate should be colorless and clear, and should not become colored when an iodo-iodized solution (R) is added. No opalescent ring should form when 5 ml filtrate and 5 ml alcohol at 95% by volume are placed one on top of the other without mixing.

 

3.3.    Desiccation Loss

In a 70 mm diameter silica dish with cover, place 2 g egg albumin. Dry in an oven at 100-105o for 6 hours. Allow to cool in the uncovered dish in a drying apparatus. Weigh. Let p be the quantity of dry residue. Weight loss should not exceed 10 pp 100.

When albumin from fresh egg is used, the real dry extract must be greater than 10.5%.

All of the limiting values given above are for dry product.

3.4.    Ash

Incinerate the dry residue obtained from the test (Par. 3.4) by gradually heating to 600o C in a muffle furnace, after dusting the egg albumin with 0.2 to 0.3 g paraffin without ash, in order to prevent the material mass from overflowing.

The proportion of ash must not exceed 6.5 pp 100.

3.5.    Total Nitrogen

Total nitrogen is determined using the technique described in the annex. The total nitrogen content must exceed 12 pp 100.

 

  1. Tests

 

4.1.    Preparation of the Test Solution

After weighing, dissolve the ash in 2 ml concentrated hydrochloric acid (R) and 10 ml water. Heat to trigger dissolution and added distilled water to obtain a volume equal to 25 times the weight of the dry egg albumin.

l of this solution contains the mineral substances from 0.04 g dry egg albumin.

 

4.2.    Heavy metals

To 10 ml of the test solution prepared according to Par. 4.1, add 2 ml of a buffer solution (pH: 3.5 (R)) and 1.2 ml thioacetaminde reagent (R). No precipitate should form. If the mixture becomes colored, the coloration should be less intense that that of the control prepared as indicated in the annex. (heavy metals content, expressed with respect to lead, should be less than 10 mg/kg.)

4.3.    Arsenic

Using the technique described in the annex, determine arsenic content in the test solution (Par. 4.1). Content l should be less than 3 mg/kg.

4.4.    Lead

Using the technique described in the Compendium, determine lead content in the test solution (Par. 4.1). Content l should be less than 5 mg/kg.

4.5.    Mercury

Using the technique described in the annex, determine mercury content in the test solution (Par. 4.1). Content l should be less than 1 mg/kg.

  1. Storage

Egg albumin should be stored in packages which ensure effective protection from moisture and external contamination in places in which temperatures are moderate.

Oxygen

COEI-1-OXYGEN Oxygen

N°SIN :948

N°CAS= 7727-44-7

  1. Object, origin and field of application

 

Gas used for operations of hyperoxygenation of must or oxygenation of wine. It is also used pure or mixed with nitrogen (reconstituted air) during alcoholic fermentation (pumping).

  1. Labelling

The label must mention the nature of the gas and refer to its composition and purity. The safety conditions should also be indicated on the package.

  1. Characteristics

Colourless, odourless gas without flavour. Non flammable, it supports combustion.

The weight in grams of a litre of oxygen under normal conditions under the pressure of 760 mm of mercury and at 20°C is 1.429 g.

A volume of water dissolves 0.0325 volume of oxygen (44 mg/l). This solubility is 0.049 ml at 0°C (70 mg/l) and a volume of alcohol dissolves 0.1428 volume of oxygen.

It is therefore possible to dissolve 44 ml of oxygen at 20°C in a litre of wine with an alcoholic strength of 12% vol.

In association with nitrogen (air) the maximum solubility of oxygen is 10.27 ml/l in water at 20°C that is about 13.9 ml in a litre of wine whose alcoholic strength is 12% vol.

  1. Test trials

The global purity of the oxygen used in oenology should be above or equal 99% in volume.

Before any measurement, it is advisable to allow the gas to escape for a few minutes in order to purge the piping.

4.1.    Chromatographic dosage

Search and determination of gases: nitrogen, carbon monoxide (less than 10 µl/l), argon, carbon dioxide (less than 300 μl/l), etc. are quickly obtained by chromatography in gaseous phase.

4.2.    Oxygen dosage

Place a sufficient quantity of ammonium hydroxide and ammonium chloride solution prepared by mixing equal volumes of water and ammonium hydroxide and by saturating with ammonium chloride at room temperature in an apparatus made up of:

  • 100 ml burette calibrated with a bi-directional stopcock,
  • pipette for gas absorption and
  • level vase with an appropriate capacity and all the connections for linking the whole set.

Fill the pipette for gas absorption with copper turnings, wire or metallic lattice or any other appropriate system.

Eliminate all the gas bubbles from the liquid in the testing apparatus. Use the test trial solution two or three times without performing any measurements.

Fill the calibrated burette, all the connections, the two stopcock openings, and the liquid uptake tube.

Entrain 100.0 ml of oxygen in the burette while lowering the level vase.

Open the stopcock facing the absorption pipette and force the oxygen to penetrate in the absorption pipette by lifting the level vase. Shake the pipette in order to favour the close contact of the liquid, gas and copper.

Continue shaking until no other decrease in volume occurs.

Entrain the residual gas again in the calibrated burette and measure its volume:

A volume of gas more than 1.0 ml should not remain.

In solution, oxygen can be determined by polarography.

  1. Packaging

Oxygen is supplied in highly resistant steel cylinders painted white, with needle valves. The resistance of these cylinders must be periodically checked.

Perlite

COEI-1-PERLIT Perlite

CAS no.93763-70-3

Expanded perlite

  1. Object, origin and field of application

Perlite is a vitreous rock of volcanic origin, belonging to the rhyolite group. Like glass, perlite is made of aluminium silicate and has a chemically bound water content of 1% to 2%.

To be used for oenological purposes, perlite must be dried at 150°C, grinded and then subjected to “expansion” by pre-heating between 200°C to 400°C followed exposing perlite in a flame at 800°C to 1100°C, which provokes swelling and causes a 60-fold increase in size.

Perlite is in white powder form and the final grain size is obtained after being grinded following expansion.

It is a filtration additive for wine.

  1. Labelling

The purity and the storage conditions must be written on the label.

  1. Limits and test trials

3.1.    Odour and taste

Perlite must not give any foreign odour or taste to the wine. Place 2.5 g of perlite in 1 litre of wine. Shake. Allow to stand 24 hours. Taste and compare to wine without an addition of perlite.

3.2.    Loss through desiccation

Place approximately 5 g of perlite in a capsule. Put in an incubator to 103 2 °C. After two hours weight loss must not be over 1%.

3.3.    Loss through calcination

Heat the dry residue obtained in point 3.2 in an oven at 550 °C. Weight loss must not be over 3%.

3.4.    pH measurement

In a 250 ml recipient, place approximately 10 g of perlite. Pour in slowly, while shaking by hand 100 ml of water to wet the product and obtain a homogenous suspension. Shake by hand from time to time or by using a magnetic stirrer. After 10 minutes, allow the suspension to stand and measure the pH level. Expanded perlite has a pH between 7.5 and 10.

3.5.    Soluble products in diluted acids

Bring 10 g of dried perlite with 20 ml of concentrated hydrochloric acid (R) and 100 ml of water to a boil. Gather the perlite on an ashless filter and wash the residue with 100 ml of distilled water. After desiccation at 100°C to 105°C and incineration, and being separated from the insoluble residue filter, it should weigh at least 9.8 g that is 98% of the dry product.

3.6.    Preparation of test trial solution

Place 200 ml of citric acid at 5 g per litre brought to pH 3 (R) and 10 g of perlite in a 500 ml flask that can be hermetically sealed. Place on a stirrer and shake 1 hour at a temperature of 20° plus or minus 2°C. Allow to stand, then filter by eliminating the first 50 ml of filtrate. Collect at least 100 ml of clear liquid.

3.7.    Iron

Carry out the determination of iron according to the procedure described in Chapter II of the International Oenological Codex using the test trial solutions prepared according to point 3.6.

Iron content must be less than 300 mg/kg.

3.8.    Lead

Carry out the determination of lead according to the procedure described in Chapter II of the International Oenological Codex using the test trial solution prepared according to point 3.6.

Lead content must be less than 5 mg/kg.

3.9.    Mercury

Carry out the determination of mercury according to the procedure described in Chapter II of the International Oenological Codex using the test trial solution prepared according to point 3.6.

Mercury content must be less than 1 mg/kg.

3.10. Arsenic

Carry out the determination of arsenic according to the procedure described in Chapter II of the International Oenological Codex using 4 ml of the test trial solution prepared according to point 3.6.

Arsenic content must be less than 5 mg/kg.

3.11. Cadmium

Carry out the determination of cadmium according to the procedure described in Chapter II of the International Oenological Codex using the test trial solution prepared according to point 3.6.

Cadmium content must be less than 1 mg/kg.

  1. Storage

Perlite must be kept in a well-ventilated dry place in watertight containers under temperate conditions.

Filter sheet

COEI-1-PLAQFI Depth filter sheets

  1. Objective, origin and scope of application

Depth filter sheets, belonging to the family of porous filter materials, are composed of organic and/or inorganic materials, and are generally used for clarification and/or microbiological stabilisation of liquids; their geometrical shapes are specific to the filtration systems defined by the manufacturers.

  1. Principle

Filtration with depth filter sheets is a physical separation process that is applied to particles ranging from 0.1 to 40 μm, allowing for the retention of bacteria, yeasts, other microorganisms and particles. The retention of the particles is based on a process of interception and adsorption within the depth filter sheets (trap deep within the sheet), and to a lesser extent a sieve effect at the outer surface, while the fluid passes through the sheets under the action of a pressure gradient. Depth filter sheets are characterised by their permeability and retention rate, which allow for different types of filtration: coarse, clarifying, or sterilising.

The treatment of musts and wines by filtration is described in the OIV International Code of Oenological Practices.

Filtration with depth filter sheets is carried out with filter apparatus and/or lenticular module housings and a feeding pump. Normally the filtration process is ended when a differential pressure of 300 kPa (3 bar) is reached. For filtration performance reasons, a differential pressure of 150 kPa (1.5 bar) should not be exceeded in applications for separating microorganisms, which should be conducted under constant flow conditions.

  1. Composition

Depth filter sheets are manufactured using raw materials specially selected for purpose, such as purified, bleached and finely fibrillated cellulose fibres from deciduous and coniferous trees, as well as different quantities of organic and inorganic filter aids like diatomaceous earth, perlite, zeolites, silicates, PVPP, synthetic wood pulp, activated carbon and/or other OIV-reviewed compounds. Polyamidoamine polymers are used as wet strength agents to improve the tensile properties in both wet and dry states, by crosslinking the cellulose fibres with covalent bonds that do not break upon wetting. The wet strength agent content should not exceed 4% of the dry fibres in the finished product. The main components and their monographs are listed in the OIV International Oenological Codex. Wet strength agents are approved for usage in hot- and cold-water filter papers[1].

  1. Labelling

The main product characteristics such as filter grade, size and batch number should be indicated on the label.

  1. Manufacture

A slurry of the above-mentioned compounds is dewatered on a wire belt with vacuum, and afterwards dried in an oven.

Through a number of procedures (refining/grinding/fibrillating) performed on the cellulose and the use of different inorganic filter aids, it is possible to obtain a whole range of permeabilities and retention rates (from 0.1 to 40 μm).

The depth filter sheets’ final characteristics (thickness, porosity, pore size, flow rate, microorganism reduction, adsorption) depend on a great number of parameters (choice of cellulose fibres from deciduous and/or coniferous trees, amount and type of inorganic material, dewatering, temperature, etc.).

Depth filter sheets can be produced in any geometrical shape using die cutting or water jet cutting and used as flat sheets, or in lenticular filter modules, capsules or other products.

  1. Depth filter sheet rinsing and sterilisation

Depth filter sheets should be flushed with water before the first filtration, according to the manufacturer’s instructions. After rinsing, the rinse water should be disposed of according to the local regulations in force. Depth filter sheets can be sterilised with hot water (85 °C) or inline steam (125 °C to max. 134 °C). In both cases, rinsing should be carried out for at least 20 minutes.

  1. Regeneration/Backwashing

When the maximum differential pressure is reached, a regeneration of the filter sheets can be performed. Depending on the nature of the blocking particles, it may be possible to extend the life of the filter with this procedure.

To regenerate the filter sheets, rinse them with cold water (15-20 °C) in the direction of filtration flow for approx. 5 minutes, then rinse with hot water (60-80°C) in the opposite direction of filtration flow for approx. 10 minutes. It is not recommended to perform more than 5 regeneration cycles per filter sheet. It is however recommended, for bacteriological safety reasons, to replace filter sheets no more than 4 weeks after their first use.

  1. Disposal

Local waste-sorting guidelines should be complied with when disposing of depth filter sheets. In principle, used filter sheets are biodegradable[2]. Ensuring the local regulations in force are followed, these can be disposed of as normal domestic waste for landfill or destroyed by thermal processes. This is provided that the depth filter sheets have not come into contact with any toxic substances during the filtration process. This statement is also applicable for depth filter sheets used in lenticular filter modules or other systems.

  1. Tests

All of the equipment (depth filter sheets, lenticular filter modules, or other parts and products of the filter system) in contact with food products must comply with the following limits.

There should be no noticeable change in the sensory (organoleptic) characteristics of the musts and wines if the depth filter sheets are used and handled according to the recommendations of the manufacturer.

The limits are determined according to values observed from use of depth filter sheets made in accordance with good manufacturing practices.

9.1.    Dry matter content in an aqueous extract

The products can be used as hot- and cold-water filter papers and filter layers for foodstuffs.

Determine the dry matter, after pre-flushing the depth filter sheet with a volume of 50 L/m2 before extraction, according to the following standards:

  • the total quantity of extractables (hot water)[3] [4] should be less than 10 mg/g,
  • the total quantity of extractables (cold water)[5] should be less than 5 mg/g,
  • the total quantity of all organic extractables should be less than 2 mg/g.

9.2.    Chloropropanol content

The 1,3-dichloro-propan-2-ol (DCP) and 3-monochloropropane-1,2-diol (MCPD) content is determined in the cold/hot water extract after pre-flushing the depth filter sheet with a volume of 50 L/m2 2 4.

The quantification of DCP and MCPD[6] is performed after the separation of the analytes in the water extract using a solid-phase extraction column. The DCP and MCPD are derivatised using heptafluorobutyrylimidazole (HFBI) and determined by GC-ECD chromatography.

9.2.1.  1,3-Dichloro-propan-2-ol (DCP) content

Proceed with determination as in point 9.2,

the 1,3-dichloro-propan-2-ol (DCP) content must be lower than 2 µg/L in a cold/hot water extract.

9.2.2.  3-Monochloropropane-1,2-diol (MCPD) content

Proceed with determination as in point 9.2,

the 3-monochloropropane-1-2,-diol (MCPD) content must be lower than 12 µg/L in a cold/hot water extract.

9.3.    Soluble metal and heavy metal content

The soluble metal content, as for that of heavy metals, is always determined in the extract after pre-flushing the depth filter sheet with a volume of 50 L/m2. For extraction, acetic acid is used at 5% (p.a.).

Extraction procedure:

  • place the filter holder horizontally, and for better ventilation, position the filter bottom-up,
  • volumetric flow rate:
  • initial volume: 25 L m-2,
  • continuously pump the initial volume in a closed system, until a volume of 100 L m-2 has been passed through the depth filter sheet (since V = 500 L m-2h-1, the duration of filtration is exactly 12 minutes),
  • in case of dripping, collect the drips and add them back into the overall volume after filtration,

once the filtration time has elapsed, stop the elution; do not drain the filter under pressure.

9.3.1.  Heavy metals

The determination of heavy metals (mg metal per kg depth filter sheet) is carried out in the extract using atomic absorption spectrometry (flame/graphite furnace):

proceed with  extraction as described in point 9.3,

the extractible heavy metal content[7] should be less than 50 ppm.

9.3.2.  Iron

proceed with  extraction of the iron as described in point 9.3,

determine the corresponding concentration of cations in the filtrate,

the iron content is determined according to the method described in Chapter II of the International Oenological Codex,

the iron content should be less than 300 mg/kg.

9.3.3.  Lead

proceed with  extraction of the lead as described in point 9.3,

determine the corresponding concentration of cations in the filtrate,

the lead content is determined according to the method described in Chapter II of the International Oenological Codex,

the lead content should be less than 5 mg/kg.

9.3.4.  Mercury

proceed with  extraction of the mercury as described in point 9.3,

determine the corresponding concentration of cations in the filtrate,

the mercury content is determined according to the method described in Chapter II of the International Oenological Codex,

the mercury content should be less than 1 mg/kg.

9.3.5.  Arsenic

proceed with  extraction of the arsenic as described in point 9.3,

determine the corresponding concentration of cations in the filtrate,

the arsenic is determined according to the method described in Chapter II of the International Oenological Codex,

the arsenic content should be less than 3 mg/kg.

9.3.6.  Cadmium

proceed with  extraction of the cadmium as described in point 9.3,

determine the corresponding concentration of cations in the filtrate,

the cadmium is determined according to the method described in Chapter II of the International Oenological Codex,

the cadmium content should be less than 1 mg/kg.

  1. Special restrictions

Depth filter sheets, lenticular filter modules and all other components and products must meet the regulatory requirements for equipment in contact with food.

  1. Storage conditions

Depth filter sheets consist of highly adsorbent materials. This product must be handled carefully during shipping and storage. Store the depth filter sheets in their original packaging in a dry, odour-free, and well-ventilated area. Do not expose the depth filter sheets to direct sunlight. When stored correctly, filter sheets do not degrade. According to the manufacturers, it is recommended to use filter sheets within 5 years after purchase.


[1] According to the respective recommendations and standards of the BfR (Germany) and FDA (United States), the GB 9685 standard, and other codes relating to foodstuffs, common consumption products and animal feed.

[2] According to standard EN 13432:2000 (composting and biodegradation).

[3] According to standard EN 647:1993 (hot water extract).

[4] According to standard EN 920:2000 (determination of dry matter content in an aqueous extract).

[5] According to standard EN 645:1993 (cold water extract).

[6] According to paragraph 35 of the LMBG (German law on foodstuffs and common consumption products), method 80.56-2.

[7] According to recommendation XXXVI/1 of the German Federal Institute for Risk Assessment (BfR).

Potassium polyaspartate

COEI-1-POTPOL Potassium polyaspartate

Chemical name

Homopolymer of potassium L-aspartate or potassium polyaspartate

Chemical formula

[C4H5NO3K]n

Topological formula

where n30

CAS No.: 64723-18 -8

 

  1. Object, origin and scop of application

 

Oenological potassium polyaspartate is prepared exclusively from L-aspartic acid. The L-aspartic acid monomer used in the process is produced by fermentation. A thermal process converts the L-aspartic acid monomer into polysuccinimide, an insoluble compound. Polysuccinimide is then treated with potassium hydroxide under controlled conditions to obtain potassium polyaspartate. The potassium polyaspartate inhibits tartaric precipitation thanks to a 'colloid protector' effect. Potassium polyaspartate is effective for the tartaric stabilisation of wines.

  1. Synonyms

 

Potassium polyaspartate, A-5D K/SD; A-5D K SD; A-5DK/SD; A-5DK; KPA.

 

  1. Labelling

 

The following indications should appear on the packaging labelling:

  • the name and sales denomination,
  • the statement ‘Product for oenological use, limited use’,
  • any additives,
  • instructions for use,
  • the batch number and potassium polyaspartate content (purity) as well as the expiry date and storage conditions (temperature, humidity and aeration),
  • the name or company name and address of the manufacturer, packager or supplier,
  • the net quantity,
  • the indication that the aspartic acid is sourced from genetically-modified organisms and the modified characteristic where relevant.

 

  1. Characterisation

 

4.1.    Description

Light-brown, odourless powder containing 90% dry matter. It is entirely soluble in water (> 1000 g/L) yet insoluble in organic solvents (< 5 g/L), with a shelf life of 4 years at room temperature.

 

4.2.    Chemical formula

Potassium polyaspartate is a polymer composed of aspartic acid units, with the following general formula: [C4H5NO3K]n, where n corresponds to the average degree of polymerisation (n30).

 

4.3.    Degree of substitution

The degree of substitution of the potassium salt is at least 91.5% (in terms of anhydrous matter), in order to guarantee optimal solubility.

Assess the degree of substitution using the method described in Annex 1.

4.4.    Molecular mass

Its average molecular mass, determined by gel permeation chromatography, is 5000 g/mol, which corresponds to the optimum efficiency of the product.

4.5.    Composition

The purity of the product is verified by assaying the aspartic acid after total hydrolysis of the polymer and by comparing this value with the theoretical content of the monomer in the potassium polyaspartate according to its molecular formula. Refer to Annex 2 for the method description.

The content of anhydrous potassium polyaspartate matter should be at least 98%.

  1. Trials

 

5.1.    Free aspartic acid content in potassium polyaspartate

The free aspartic acid content should be 2.0%.

Carry out the determination according to the method described in Annex 3.

 

5.2.    Humidity – Loss due to dehydration

Determine the loss in mass of a gram of dry product kept in an oven for 12-24 hours at 1052 °C. The mass should be constant and the loss in mass should be less than 10%.

 

5.3.    Metal content

Before determining the metals, mineralise the sample by means of acid digestion (HNO3, H2O2 and HCl). Conduct the mineralisation in a microwave oven. The sample should not be crushed or dehydrated before mineralisation.

The reagents used for mineralisation are as follows: HNO3 (65%) (Suprapur or similar), HCl (37%) (Suprapur or similar) and H2O2 (35%).

Introduce the polyaspartate sample (between 0.5 and 2 g) into a 100-mL calibrated flask before adding 25 mL HNO3, 2 mL HCl and 3 mL H2O2. At this stage, subject the mixture to digestion in a microwave oven with a maximum power of 1200 W: 60% power for 1 min, 30% for 10 min, 15% for 3 min and 40% for 15 min. Subsequently, make the calibrated flask up to volume with double-distilled water. The determination of the metals is practised on the solution thus obtained.

 

5.3.1.  Iron

Determine the iron according to the method described in Chapter II of the International Oenological Codex. The iron content should be below 10mg/kg.

5.3.2.  Arsenic

Determine the arsenic according to the method described in Chapter II of the International Oenological Codex. The arsenic content should be below 3 mg/kg.

5.3.3.  Lead

Determine the lead according to the method described in Chapter II of the International Oenological Codex. The lead content should be below 2 mg/kg.

 

5.3.4.  Mercury

Determine the mercury according to the method described in Chapter II of the International Oenological Codex. The mercury content should be below 1 mg/kg.

 

5.3.5.  Cadmium

Determine the cadmium according to the method described in Chapter II of the International Oenological Codex. The cadmium content should be below 1 mg/kg.

 

Annex 1: Determination of the degree of substitution

 

  1. Principle

The degree of substitution of commercial potassium polyaspartate is determined by the analysis of the potassium content using the ICP-OES method.

The determination of potassium is conducted using a calibration curve obtained by injecting five different concentrations of a reference standard solution.

To calculate the degree of substitution, the potassium concentration measured is compared to the theoretical content at 100% substitution.

 

  1. Equipment
  • 100-mL Volumetric flasks (class A)
  • Cyclonic atomisation chamber, standard quartz torch
  • Ultrasonic bath
  • Membrane filtration system with 0.45 m porosity

 

  1. Reagents
  • 65% Nitric acid (HNO3)
  • 10 000 mg/L Potassium (K) standard solution (potassium ICP/DCP standard solution with 10 000 μg/mL 5% HNO3)
  • Double-distilled water with superior resistivity of 10 MΩ.cm
  • Aqueous solution acidified with 0.5% HNO3 (calibration blank), to be used as a diluent for the preparation of the calibration solutions

Calibration solutions prepared by dilution of the stock solution (point 1.3.2); the reference values are indicated below:

 

 

STD 1

STD 2

STD 3

STD 4

STD 5

Potassium (mg/L)

200

400

600

1000

2000

 

  1. Procedure

The preparation to be analysed (KPA) is dissolved in double-distilled water.

5000 mg/L KPA solution (a): weigh around 500 g (note the exact weight) directly into a 100-mL calibrated flask, make up to volume with double-distilled water (1.3.3) and stir in an ultrasonic bath (1.2.3) for at least 10 minutes. Filter using membranes with 0.45 μm porosity.

Prepare the five-point calibration curve with the standard solutions as indicated in point 1.3.5.

The results should be calculated from the average of three measurements.

If the concentration lies outside the calibration curve, the sample should be diluted so that its concentration falls within the calibration curve.

To calculate the degree of substitution, compare the potassium concentration measured to the theoretical content established at 100% substitution (see point 1.5).

  1. Calculations

The potassium content is calculated by the processor of the acquisition software. The calculation to be conducted is as follows:

(a)

where:

  • A: concentration of sample in mg/L
  • A': concentration of diluted sample in mg/L
  • n: dilution factor

The percentage of potassium in the KPA sample, expressed in dry weight, is calculated using formula (b):

(b)

where:

  • A: result of equation (a)
  • w: potassium polyaspartate in mg/L
  • h%: humidity of the sample, as a percentage

The degree of substitution (DS) is calculated using equation (c):

(c)

where:

  • MAK: atomic mass of potassium
  • MMKPAmonomer: calculated molecular mass of the polyaspartate monomer

Annex 2: Determination of the purity of potassium polyaspartate

 

  1. Principle

Analysis by HPLC-FLD of the free aspartic acid content after acid hydrolysis.

The principle consists of determining the free aspartic acid by HPLC after acid hydrolysis of the KPA. This acid hydrolysis takes place under conditions allowing for the complete depolymerisation of the KPA:

Potassium polyaspartate

Aspartic acid

  1. Equipment/ Apparatus
    1.     Hot plate for acid hydrolysis
    2.     4-mL Tinted-glass vials with screw cap
    3.     0.1 mg Precision weighing balance
    4.     Calibrated flasks
    5.     HPLC system including a quarternary pump, an automatic sampler, a thermostat and a fluorometric detector (FLD)
    6.     C18 column (e.g. Syncronis aQ C18, 4.6 x 250 mm; 5 μm [Thermo])
    7.     Filtration system with membranes of 0.2 µm porosity
  1. Reagents and sample preparation
    1.     For acid hydrolysis
      1.   Potassium metabisulphite solution (Na2S2O2) (CAS No. 16731-55-8) at a concentration of 10 g/L
      2.   6 M Hydrochloric acid (HCl)
      3.   5 M Sodium hydroxide (NaOH)
      4.   Double-distilled water with superior resistivity of 10 m.cm
      5.   Potassium polyaspartate

3.2.    For sample preparation

3.2.1.  Aminocaproic acid (C6H13NO2, CAS No.: 60-32-2)

 

  1. Procedure

The procedure comprises three steps:

  • hot acid hydrolysis of the potassium polyaspartate sample,
  • preparation of the samples for analysis by HPLC-FLD of the standard solutions that will determine the aspartic acid concentration,
  • analysis of the free aspartic acid after hydrolysis by HPLC (see Annex 3).

4.1.    Phase 1: acid hydrolysis

4.1.1.  Transfer into a 4-mL vial (2.2.2):

  • 0.2 mL 10 g/L sodium metabisulphite solution (2.3.1),
  • 0.5 g potassium polyaspartate weighed to the nearest mg,
  • 2mL 6N HCl (2.3.2).
    1.   Heat to 108 2°C for 72 hours (2.2.1).
    2.   Transfer to a 10-mL calibrated flask, add 2.4 mL 5 M NaOH (2.3.3) and make up to volume with double-distilled water (2.3.4).
  1.     Phase 2: preparation of the sample for HPLC analysis
    1.   Microfilter 5 mL of medium (2.4.1.3) at 0.20 μm (2.2.7) in a 20-mL calibrated flask.
    2.   Add 0.2 mL internal standard (aminocaproic acid) (2.3.6).
    3.   Make up to volume with double-distilled water.
  2.     Phase 3: Analysis of samples by HPLC (see Annex 3)
  1. Calculations

The polyaspartate concentration (KPA) is calculated as follows:

  • KPA (mg/L) = (hydrolysed aspartic acid – free aspartic acid before hydrolysis) x fKPA
  • where fKPA = 1.15, which is the conversion factor of KPA into aspartic acid, calculated based on the ratio between the molecular mass of the KPA monomer (average MM of KPA A5DK SD monomers=154) and the molecular mass of aspartic acid (133.1), as per the equation:

where the free aspartic acid is determined according to Annex 3.

 

Annex 3: Determination of free aspartic acid

  1. Principle

The determination of aspartic acid in potassium polyaspartate as it was produced is carried out by HPLC coupled with fluorometric detection (FLD), after derivation of aspartic acid with ortho-phthalaldehyde (OPA). Potassium is determined using a calibration curve obtained by injecting the reference standard solutions.

  1. Equipment/ Apparatus
  • Calibrated flasks
  • HPLC system including a quarternary pump, an automatic sampler, a thermostat and a fluorometric detector (FLD)
  • C18 column, e.g. Syncronis aQ C18, 4.6 x 250 mm; 5 μm
  1. Reagents
    1.     Aspartic acid (D,L-aspartic acid, C4H7NO4 ≥ 99%, CAS No.: 617-45-8)
    2.     Solution 1: 8000 mg/L aspartic acid in double-distilled water
    3.     Solution 2: 200 mg/L aspartic acid in double-distilled water
    4.     Aminocaproic acid (C6H13NO2, CAS No.: 60-32-2)

1000-mg/L aminocaproic acid stock solution in double-distilled water

Calibration solutions prepared by dilution of solution 1 (point 3.3.2) and solution 2 (3.3.3), whose reference values are indicated below:

 

STD 1

STD 2

STD 3

STD 4

STD 5

STD 6

mL H2O

18.8

19.0

15.0

19.750

19.375

18.750

mL Solution 1

-

-

-

0.250

0.625

1.250

mL Solution 2

0.2

1.0

5.0

-

-

-

Aspartic acid (mg/L)

2

10

50

100

250

500

3.5.    Methanol for HPLC

3.6.    Tetrahydrofuran for HPLC

3.7.    Anhydrous sodium acetate (CAS No. 127-09-3)

3.8.    Acetonitrile (CH3CN) for HPLC

3.9.    Sodium tetraborate decahydrate (Na2B4O7·10H2O, CAS No. 1303-96-4)

O-phthalaldehyde (OPA): (C8H6O2 ≥ 99%, CAS No.: 643-79-8)

3.10. Mercaptoethanol: (C8H6OS ≥ 99%, CAS No.: 60-24-2)

3.11. Double-distilled water with superior resistivity of 10 MΩ.cm

3.12. Derivation solution: in a 10-mL calibrated flask, introduce 100 mg OPA, 200 mL mercaptoethanol and 1 mL methanol, then make up to volume with a pH 10.5 buffer solution of 0.1 M sodium tetraborate decahydrate.

3.13. The solution should be prepared just before use since it degrades over the day following its preparation.

  1. Mobile phases

 

[Channel A]: ultra-pure water

[Channel B]: 0.05 M sodium acetate buffer/tetrahydrofuran (96:4; v/v)

[Channel C]: methanol

Channel D]: acetonitrile

  1. Procedure

The method consists of a reaction constituting the derivation of aspartic acid with the O-phtalaldehyde (OPA); the recovery rate for this process is 100%.

The instrumental parameters are as follows:

  • temperature of the column: 40 °C,
  • wavelength (λ): FLD Ex 340 nm, Em 450 nm,
  • the separation is carried out in gradient mode (see point 3.4, Mobile phases):

Time (min)

% B

% C

% D

Flow (mL/min)

0.00

100.0

0.0

0.0

1.1

3.00

100.0

0.0

0.0

1.1

15.00

50.0

25.0

25.0

1.1

17.00

84.0

8.0

8.0

1.1

18.00

100.0

0.0

0.0

1.1

Run time: 21 min + 2 min downtime

Prepare the calibration solutions by mixing 5.0 mL of the standard solution (3.3.6) and 0.2 mL of the internal standard solution (3.3.5) in a 20-mL calibrated flask, then make up to volume with double-distilled water and stir.

Dilute 5.0 μL of the sample (Annex 2, point 2.4.2) with 20 μL methanol, then derive with 0.5 μL OPA. Mix 10.0 μL of the thus-obtained solution 10 times in the injector, then inject after 0.5 min.

If the results exceed the upper limit of the calibration curve, dilute the sample and repeat the analytical procedure.

  1. Calculations

The concentration of aspartic acid in the sample, expressed in mg/L, is obtained by applying the following formula:

where:

  • Y: concentration of aspartic acid in the sample, in mg/L
  • A: peak area of the chromatogram
  • f: response factor of the chromatogram peak
  • d: dilution factor

Annex 4: Method of determination of the mean molecular mass of
potassium polyaspartate

  1. Introduction

The effectiveness of potassium polyaspartate used in tartaric stabilisation depends on the parameter of mean molecular mass, therefore it is necessary to have a method to determine the latter.

  1. Objective

Parameter to be determined: mean molecular mass, expressed in g/mol.

  1. Definitions

GPC/SEC: gel permeation chromatography.

  1. Principle

The determination of the mean molecular mass requires the use of gel permeation chromatography (GPC/SEC). This is a type of molecular exclusion chromatography used to separate molecules according to their size.

  1. Reagents and equipment

 

5.1.    Double-distilled water with resistivity of > 10 MΩ.cm at 25°C

5.2.    Anhydrous sodium sulphate (Na2SO4) with a purity of ≥ 99% (CAS No. 7757-82-6)

5.3.    Anhydrous monobasic potassium phosphate (KH2PO4) with a purity of ≥ 99% (CAS No. 7787-77-0)

5.4.    Sodium azide with a purity of 99% (CAS No. 26628-22-8). In using sodium azide, preventative measures should be taken to mitigate the risks of toxicity and instability (explosion)

5.5.    Sodium polyacrylate salts with molecular masses of between 1000 and 1250 g/mol (CAS No. 9003-04-7)

5.6.    L-aspartic acid with a purity of 98% (CAS No. 56-84-8)

5.7.    Potassium polyaspartate with a purity of ≥ 98% (CAS No. 64723-18-8)

 

  1. Apparatus

6.1.    Filtration system with porosity of 0.22 μm

6.2.    GPC column adapted to molecular mass intervals of between 500 and 10,000 g/mol

6.3.    UV detector

  1. Preparation of the sample

 

Prepare a volume of around 15 mL of 0.1% potassium polyaspartate solution (5.7) in the mobile phase (8.1) and filter it on a 0.22 μm filter (6.1). The polyaspartate solution in the buffer becomes unstable after 3 hours. Fresh solutions should therefore be prepared before each injection.

7.1.    Calibration

Prepare 0.1% solutions for each standard (5.5 and 5.6) in the mobile phase (8.1).

Inject the standards to be used in order of decreasing molecular mass.

The calibration curve is obtained by representing the retention time (variable x) on a graph as a function of the logarithm of the mean molecular mass of the standards (5.5) (variable y) (r2≥ 0.99).

  1. Procedure

 

8.1.    Preparation of the mobile phase

The mobile phase is a buffer solution composed of 0.1 M Na2SO4 (14.2 g/L) (5.2), 0.01 M KH2PO4 (1.36 g/L)(5.3) and 20 mg/L sodium azide (5.4) in double-distilled water (5.1) filtered using a 0.22-µm filter. The buffer solution should be used within 4 days of preparation.

8.2.    Chromatography conditions

Flow rate: 0.7 mL/min

Column: UltrahydrogelTM Linear or similar, dimensions: 7.8 x 300 mm, filled with particles of an average diameter of 6 μm

Column temperature: 50°C

Run time: 40 min

Injection volume: 200 μL

UV detector: wavelength of 220 nm

  1. Calculations

Compare the chromatographic profile corresponding to the sample with that of the standards (5.5). Calculate the molecular mass of polyaspartate, expressed in g/mol, according to the retention time of the sample and the calibration curve.

Potassium alginate

COEI-1-POTALG Potassium alginate

Kalii Alginas

  1. Objective, Origin and Scope of Application

This is a potassium salt of alginic acid extracted from various types of pheophyceae algae, in particular laminaria, by means of alkaline digestion and purification.

It is a clarifying agent used during the second fermentation in the bottle for sparkling wines.

  1. Labelling

The label should indicate the product's purity and safety and storage conditions.

  1. Properties

Potassium alginate is a white or yellowish powder which is nearly odorless and itasteless and which is composed of fiber fragments, when seen under a microscope.

With water, it produces a viscous solution.  The pH of this solution is typically between 6 and 8.  It is soluble in strong alcohol and in most organic solvents.

A gelatinous calcium alginate precipitate forms if a 0.50 ml of 20 pp 100 calcium chloride solution (R) is added to 5 ml of an aqueous 1 pp 100 potassium alginate (m/v) solution.

A gelatinous alginic acid precipitate form if 1 ml of sulfuric acid diluted to 10 pp 100 (R) is added to 10 ml of an aqueous 1 pp 100 potassium alginate (m/v) solution.

  1. Tests

4.1.    Starch

Add 5 ml of iodinated water (R) to 5 ml of aqueous 1 pp 100 potassium alginate (m/v) solution. No blue coloration should develop.

4.2.    Gelatin

Add 1 ml of 2 pp 100 hot tannin (R) to 10 ml of aqueous 1 pp 100 potassium alginate (m/v) solution. No precipitate should form.

4.3.    Desiccation loss

Desiccation loss determined up to constant weight of a precisely-weighed  sample  of approximately 1 g. The weight loss of the potassium alginate at 100-105 °C should not be greater than 15 pp 100.

All limits indicated below are for dry product

4.4.    Sulfur Ash

The sulfur ash content using the method indicated in the Annex is determined by analyzing the residue from the previous test (4.3). The concentration of sulfur ash in the potassium alginate sulfuric ashes should not exceed 40 pp 100.

4.5.    Preparing the Solution for Tests

In a silica dish, calcine a sample whose weight corresponds to 2.5 g of dry product, without exceeding 550 °C.  Take up the residue with 10 ml of water and 2 ml of concentrated nitric acid (R).  Decant in a 50 ml volumetric flask.  Add 2 ml of concentrated ammonium hydroxide (R).  Top off to 50 ml with distilled water. Filter.

4.6.    Sulfates

To 2 ml of the solution prepared for tests under paragraph 4.5, add 2 ml of dilute hydrochloric acid (R) and top off to 20 ml. Add 2 ml of 10 pp 100 barium chloride solution (R).  The mixture should be clear; or else, the opalescence observed after 15 minutes should be less intense than that observed in a control prepared as indicated in the Annex. (Sulfate content expressed in terms of sulfuric acid should be less than 1 g/kg).

4.7.    Chlorides

Add 5 ml of dilute 10 pp 100 nitric acid (R), 14 ml of distilled water and 0.5 ml of 5 pp 100 silver nitrate (R) to 1 ml of the test solution (Par. 4.5). Any opalescence that appears should be less intense than that of a control prepared as indicated in the Annex. (Chloride content, expressed in terms of hydrochloric acid, should be less than 1 g/kg).

4.8.    Iron

Add 8 ml of water, 1 ml of concentrated hydrochloric acid (R), 1 drop of 1 pp 100 potassium permanganate solution (R) and 2 ml of 5 pp 100 potassium thiocyanate solution (R) to 2 ml of the test solution prepared under paragraph 4.5.

Any red coloration that appears should be less intense than that of a control prepared with 3 ml of iron (III) solution in a concentration of  0.010 g iron per liter (R), 7 ml of water and the same quantities of concentrated hydrochloric acid (R) and 5 pp 100 potassium thiocyanate solution (R).  (Iron content should be less than 300 mg/kg).

Iron contant can also be determined by atomic absorption spectometry, by implementing the technique described in the compendium.

4.9.    Cadmium

Using the technique described in the annex, determine cadmium content in the test solution (Par. 4.5). Content should be less than 1 mg/kg.

4.10. Lead

Using the technique described in the Compendium, determine lead content in the test solution (Par. 4.5). Content should be less than 5 mg/kg.

4.11. Mercury

Using the technique described in the annex, determine mercury content in the test solution (Par. 4.5). Content should be less than 1 mg/kg.

4.12. Arsenic

Using the technique described in the annex, determine arsenic content in the test solution (Par. 4.5). Content should be less than 3 mg/kg.

4.13. Sodium

Using flame photometry, determine sodium content in the test solution (Par. 4.5). Sodium content should be less than 1 pp 100.

  1. Storage

Potassium alginate should be stored in hermetically sealed packages.

Calcium (Alignate)

SIN N°: 402

  1. Object, origin and scope of application

Calcium alginate is obtained from a 1 % aqueous solution of potassium alginate or alginic acid placed in contact with a 20 % aqueous solution of calcium chloride. Beads of calcium alginate can be produced by dropping droplets of potassium alginate solution into a calcium chloride solution.

Beads of calcium alginate, dry or wet, can contain yeasts or lactic bacteria, dry or wet. They are used for foam forming purposes in the bottle for sparkling wine or to restart alcoholic fermentation in still wines or to start the malolactic fermentation.

These beads can be coated with a double layer of potassium or calcium alginate or with colloidal silica to prevent the precipitation of the yeasts or bacteria incorporated into the beads.

  1. Labelling

The label should indicate the product’s purity and the safety and storage conditions for calcium alginate, the yeasts or bacteria incorporated into the beads, the expiration date and the lot number.

  1. Characteristics

Calcium alginate is a translucent gel, which is insoluble in water and wine. It only dissolves in a sodium metaphosphate solution.

An alginic acid precipitate is also produced if 1 ml of sulfuric acid diluted to 10 % (R) is added to 10 ml of an aqueous 1 % (m/v) suspension of calcium alginate.

Potassium anhydrous sulfite

COEI-1-POTANH Potassium anhydrous sulfite

Potassium pyrosulfite

Potassium disulfite

Potassium metabisulfite

Kalii metabisulfis

= 222.3

SIN No. 224

  1. Objective, Origin and Scope of Application

Potassium anhydrous sulfite, commonly called potassium metabisulfite, is used because of the sulfur dioxide it makes available. Potassium metabisulfite, which is sold in powdered form, contains 52-55% by weight SO2.

There are regulatory limits restricting the sulfur dioxide content of wines.

  1. Labelling

The label should indicate the product's purity as well as its safety and storage conditions.

  1. Centesimal Composition

Sulfur dioxide

57.63

Potassium

35.17

  1. Solubility

Water at 20 °C

454.5 g/l

Alcohol, 95% by vol.

insoluble

  1. Identifying Properties

5.1.    5 ml of aqueous 10 pp 100 (m/v) solution treated with 5 ml of 1/10 diluted sulfuric acid (R) releases sulfur dioxide and reduces iodine and potassium permanganate.

5.2.    The 10 pp 100 (m/v) aqueous solution is acidic as indicated by methyl red (R) of (pHapproximately 5).

5.3.    The 1 pp 100 (m/v) aqueous solution produces potassium-based reactions.

  1. Tests

6.1.    Preparing the Test Solution in a Concentration of 10 pp 100

Prepare a solution in a concentration of 10 pp 1000 (m/v).

6.2.    Preparing a Test Solution in a Concentration of 1 pp 100

Prepare a 1 pp 100 (m/v) solution by diluting the previous solution (6.1) to 1/10.

6.3.    Lead

Using the technique described in the Compendium, determine the lead content in the 10 pp 100 test solution (6.1). (Lead content should be less than 5 mg/kg.)

6.4.    Mercury

Using the technique described in the annex, determine the mercury content in the 10 pp 100 test solution (6.1). (Content should be less than 1 mg/kg.)

6.5.    Arsenic

Using the technique described in the annex, determine the arsenic content in the 10 pp 100 test solution (6.1). (Content should be less than 3 mg/kg.)

6.6.    Selenium

Weigh 2.60 g potassium anhydrous sulfite, a quantity which contains 1.5 g sulfur dioxide.  Dissolve it under heat in 7 ml of distilled water and 2 ml of concentrated hydrochloric acid (R). Let cool, then add 3 ml of formaldehyde solution (R). Let sit for 10 minutes.  Place the tube in a 100 °C water bath and add 50 mg of pulverized potassium anhydrous sulfite which is free of selenium (R). Leave the tube in the 100 °C water bath for 15 minutes.  If a pink coloration develops, it should be less intense than that of a control prepared in the same way using 2.60 g of selenium-free potassium anhydrous sulfite (R) to which was added 0.45 ml of a selenium dioxide solution in a concentration of 100 mg of selenium per liter (R). (Selenium content, with respect to the sulfur dioxide, should be less than 10 mg/kg).

6.7.    Sodium

Prepare 10 ml of a 1 pp 100 (m/v) solution as indicated in paragraph 6.2 with 2 ml of acetic acid (R).  Evaporate the solution in a 100 °C water bath until it is reduced to 1/2.

Pour into a 100 ml volumetric flask.  Fill with water to the gauge line. Quantitatively analyze the sodium using flame photometry. (Sodium content should be less than 2 pp 100).

6.8.    Chlorides

Place 0.5 ml (concentration: 10 pp 100) of solution as prepared under paragraph 6.1 in a dish with 10 ml of water and 3 ml of 10 pp 100 sulfuric acid solution (R).  Evaporate in a 100 °C water bath to reduce the volume to 5 ml.  Decant in a test tube. Bring the volume up to 15 ml, then add 5 ml of 10 pp 100 nitric acid (R) and 0.5 ml of 5 pp 100 silver nitrate solution (R).  The liquid should remain clear; or else, any clouding which occurs should be less intense than that in a control prepared as indicated in the Annex. (Chloride content, expressed in terms of hydrochloric acid, should be less than 1 g/kg).

6.9.    Iron

Using the technique described in the Compendium, determine lthe iron content in the 10 pp 100 (m/v) test solution (6.1) using atomic absorption spectrophotometry. (Iron content should be less than 50 mg/kg SO2.)

  1. Quantitative Analysis

 

Sulfur dioxide - Place 50 ml of a disodium ethylene diamine tetra-acetate solution (120 mg per liter) in a 200 ml conical flask. Add 10 ml of the freshly prepared 1 pp 100 potassium anhydrous sulfite solution and titrate with 0.05M iodine. Let  n be the volume in ml ; 1 ml of 0.05M iodine corresponds to 3.2 mg of sulfur dioxide.

Sulfur dioxide content per 100 g: 3.2n

Potassium anhydrous sulfite should contain at least 51.8 pp 100 sulfur dioxide.

  1. Storage

This product reacts with air and should be kept in hermetically sealed containers.

Potassium hydrogen carbonate

COEI-1-POTBIC Potassium hydrogen carbonate

Potassium bicarbonate

KHC

  1. Objective, origin and scope of the application

This product is used to deacidify musts and wines. The transport of potassium ions causes salification of free tartaric acid and the formation of potassium hydrogen tartrate.

The use of this product is subject to regulation.

  1. Labelling

The label should indicate the product's purity and storage and storage conditions.

  1. Centesimal composition

Carbon dioxide

43.97

Potassium

39.06

  1. Properties

 

Potassium hydrogen carbonate is found in the form of a white, odorless powder which is slightly hygroscopic.  It leads to carbonate-based reactions.

  1. Solubility

Water at 20 °C

600 g/l

Insoluble in alcohol, 95% by vol.

Soluble with effervescence in dilute acid solutions (acetic, hydrochloric, etc.).

 

  1. Tests

 

6.1. Desiccation Loss

After 4 hours of desiccation in an oven at 105 °C, weight loss should be no more than 2 pp 100.

6.2. Preparing the Solution for Tests

Place 10 g of potassium hydrogen carbonate in a 100 ml volumetric flask and  fill with water.

 

6.3. Substances Insoluble in Water

Filter the solution prepared for testing under Paragraph 6.2. The residue, when dried at 105 °C then calcined at 550 °C, should not be greater than 0.1 g (or 1 pp 100).

6.4. Iron

Using the atomic absorption spectometry technique detailed in the Compendium, analyze the iron content in the test solution (6.2).

6.5. Lead

Using the technique set forth in the Annex, analyze lead content in the test solution (6.2). (Lead content should be less than 5 mg/kg).

6.6. Mercury

Using the technique described in the Annex, determine the mercury content in the test solution (6.2). (Content should be less than 1 mg/kg.)

6.7. Arsenic

Using the technique described in the Annex, determine the arsenic content in the test solution (6.2). (Content should be less than 3 mg/kg.)

6.8. Sodium

Analyze the sodium content in the test solution (6.2) using flame photometry.  (Sodium content should be less than 1 pp 100).

6.9. Potassium Hydrogen Carbonate Content

Dissolve approximately 2 g of a test sample, weighed precisely, in 50 ml of 1M hydrochloric acid solution. Titrate the excess hydrochloric acid using a 1M sodium hydroxide solution in the presence of methyl red.

The product intended for wine-making should contain a minimum of 98 pp 100 potassium hydrogen carbonate.

  1. Storage

 

Potassium hydrogen carbonate should be stored in airtight containers away from moisture.

Potassium hydrogen sulfite

COEI-1-POTBIS Potassium hydrogen sulfite

Potassium bisulfite

Potassium acid sulfite

= 120.2

SIN No. 228

  1. Objective, origin and scope of application

 

Potassium hydrogen sulfite is used in oenology because of the proportion of sulfur dioxide it contains.

  1. Labelling

The label should indicate the weight per liter or per kilogram of sulfur dioxide and the storage and safety conditions.

There are regulatory limits restricting the sulfur dioxide content in wines.

  1. Centesimal Composition

SO2

53.30

K

32.53

  1. Properties

Potassium hydrogen sulfite is found in the form of a colorless or slightly yellow solution obtained by passing a current sulfur dioxide through an aqueous potassium hydroxide solution.

Hydrogen sulfite solutions are unstable and should not contain less than 70 g/l or more than 200 g/l SO2.

  1. Identifying characteristics

Potassium hydrogen sulfite solutions yield reactions of potassium and sulfur dioxide and are slightly acidic (pH of approximately 5).

  1. Tests

The tests are identical to those detailed in the monograph on potassium anhydrous sulfite, as are the limiting content levels for lead, mercury, iron, arsenic, selenium and chlorides.

Quantitative Analysis

Place 50 ml of cold water in a 200 ml conical flask, then add 5 ml of potassium hydrogen sulfite solution. Dilute so that the solution has a concentration of approximately 1 pp 100 SO2 and titrate with 0.1M iodine in the presence of starch. Let n be the volume of iodine used.

The sulfur dioxide (SO2) content of the solution, expressed in pp 100 (m/v), is 0.64 x n (concentration cannot be less than 70 g/L).

  1. Storage

Potassium hydrogen sulfite solutions containing more than 15 pp 100 (m/v) of sulfur dioxide must not be stored at low temperatures, in order to avoid the risk of crystallization.

Potassium hydrogen tartrate

COEI-1-POTBIT Potassium hydrogen tartrate

Potassium L-2,3-dihydroxy hydrogen butanedioate

Monopotassic tartrate

Potassium bitartrate

COOH-CHOH-CHOH-COOK = 188.17

SIN No. 336 i

  1. Objective, origin and scope of application

This addition of potassium hydrogen tartrate, commonly called potassium bitartrate, promotes the crystallization of tartaric acid salts when cold-treating wines.

  1. Labelling

 

The label should indicate the product's purity, size grading, and safety and storage conditions.

  1. Properties

This is an anhydrous monopotassic salt of L(+) tartaric acid C4H5O6K.

It is found in the form of white crystals or white granulated powder having a slightly acidic taste.

  1. Solubility

 

Water at 20 °C

5.2 g/l

Water at 100 °C

61 g/l

Insoluble in alcohol

 

  1. Tests

5.1.    Desiccation Loss (Volatile Substances)

After 4 hours of drying in an oven at 105 °C, weight loss should be no more than 1 pp 100.

5.2.    Preparing the Solution for Tests

Place 10 g potassium hydrogen tartrate, 50 ml water and 1 ml concentrated hydrochloric acid in a 100 ml volumetric flask.  Stir and fill to the top with water.

Perform the same tests on this solution as those indicated in the monograph on L(+) tartaric acid (with the exception of chlorides), and observe the same limits.

5.3.    Sodium

Using the flame photometry technique described in the Compendium, analyze sodium conent in the test solution (5.2). (Sodium content should be less than 1 pp 100,).

5.4.    Iron

Add 1 ml concentrated hydrochloric acid (R) and 2 ml potassium thiocyanate solution having a concentration of 5 pp 100 (R) to 10 ml test solution (5.2). The red color produced should not be more intense than that of a control prepared using 1 ml of an iron (III) salt solution in a concentration of 0.010 g iron per liter (R), 9 ml water, and the same quantities of the same reagents (content should be less than 10 mg/kg).

Iron can also be analyzed quantitatively by atomic absorption spectometry, in accordance with the technique described in the Compendium.

5.5.    Lead

Using the technique described in the Compendium, determine lead content in the test solution (5.2). (Lead content should be less than 5 mg/kg.)

5.6.    Mercury

Using the technique described in the annex determine the mercury content in the test solution (5.2). (Mercury content should be less than 1 mg/kg.)

5.7.    Arsenic

Using the technique described in the annex, determine the arsenic content in the test solution (5.2). (Arsenic content should be less than 3 mg/kg.)

 

5.8.    Oxalate

Using the technique described in the annex, determine oxalate content in the test solution (5.2). (Oxalate content, expressed in the form of axalic acid, should be less than 100 mg/kg.)

  1. Storage

Potassium hydrogen tartrate should be stored in hermetically sealed containers.

Potassium caseinate

COEI-1-POTCAS Potassium caseinate

  1. Objective, origin and scope of application

Potassium caseinate is obtained from fresh or pasteurized skimmed milk by acid coagulation of the casein (see monograph), neutralization using potassium hydroxide and drying with a spray dryer. It is used for the fining of wines.

  1. Labelling

 

The label should indicate the product's purity and safety and storage conditions.

  1. Properties

Potassium caseinate is a white powder with a slightly yellowish tint, whose characteristic odor is typical of that of milk proteins.  It exhibits no unusual odor or taste.  It yields a colloidal solution in water.

  1. Tests

4.1.    pH

In a water solution with 5 g of potassium caseinate per 100 ml of water, the pH should be between 6.0 and 8.0 0.5

4.2.    Desiccation loss

As determined upon constant weight for a sample of approximately 2 g, weight loss at 100-105 °C should not be greater than 10%.

All of the following limiting values are for dry product.

4.3.    Ash

Without exceeding 550 °C, burn the residue from the desiccation loss test. The weight of the ash should not be greater than 7%.

4.4.    Preparing the Test Solution

After weighing, dissolve the ash in 2 ml of concentrated hydrochloric acid (R) and 10 ml of water.  Heat to trigger dissolution and fill to 50 ml with water.

4.5.    Potassium

Determine the potassium content using flame photometry on the test solution prepared under Paragraph 4.4. (Potassium content should be less than 2 pp 100).

4.6.    Iron

Determine the iron content using atomic absorption spectrophotometry on the test solution prepared under paragraph 4.4. (Iron content should be less than 200 mg/kg).

4.7.    Lead

Using the technique described in the Compendium, determine the lead content in the test solution (4.4). (Lead content should be less than 5 mg/kg.)

4.8.    Mercury

Using the technique described in the annex, determine the mercury content in the test solution (4.4). (Mercury content should be less than 1 mg/kg.)

4.9.    Arsenic

Using the technique described in the annex, determine lead the arsenic content  in the (4.4. (Arsenic content should be less than 3 mg/kg.)

4.10. Total Nitrogen

Place about 0.20 g of precisely-weighed potassium caseinate in a mineralization cucurbit with 15 ml of concentrated sulfuric acid (R), 2 g of mineralization catalyst (R) and proceed as indicated in the method described in the Annex. Total nitrogen content should not be less than 13 pp 100.

 

4.11. Fats

The fat content measured as per the method described in the Annex should not exceed 2 pp 100 by weight.

  1. Storage

 

Potassium caseinate should be stored in airtight containers, for example, in paper bags lined with polyethylene, at a temperature of between 5 and 20 °C at a relative humidity of less than 65%. The shelf life of potassium caseinate is 24 months.

Potassium hexacyanoferrate (II)

COEI-1-POTFER Potassium hexacyanoferrate (II)

Potassium ferrocyanide

Cianuretum ferroso - Kalium

[Fe], 3 = 422.40

SIN NO. 536

  1. Objective, origin and scope of application

Potassium hexacyanoferrate (II) is found in the form of yellow, monoclinic crystals having no odor and with a bitter, salty flavor. Density is 1.935 at 20 °C.

This salt is slightly efflorescent and begins to lose its water of crystallization at approximately 60 °C. In an oven at 100 °C, it dehydrates completely, becoming white and hygroscopic.

Freshly prepared aqueous solutions are yellow and decay slowly in light with the release of alkalinity.  They take on a greenish color by forming a small quantity of Prussian blue.

Potassium hexacyanoferrate (II) is used to remove iron (III) and iron (II) ions in wines, which could cause iron breakdown. It is also used to avoid copper breakdown. It is used, more generally, to reduce the heavy metal content.

It uses must be strictly controlled by mandatory monitoring.

  1. Labelling

The label should indicate the product's purity as well as its safety and storage conditions.

  1. Identifying properties

The aqueous solution at 1 pp 100 (m/v) yields hexacyanoferrate (II) ion and potassium reactions, particularly with the iron (III) cation, resulting in a dark blue iron (III) hexacyanoferrate (II) (Prussian blue) precipitate which is insoluble in dilute mineral acids.  With the copper cation, it forms a purple copper (II) hexacyanoferrate (II) precipitate that is insoluble in dilute mineral acids.

  1. Solubility

Water at 20 °C

265 g/l

Water at 100 °C

740 g/l

  1. Tests

5.1.    Desiccation Loss

Place 1 g of powdered potassium hexacyanoferrate (II) in a calibrated dish and dry in an oven at 100 °C until it has a constant weight. Weight loss should be between 12 and 13 pp 100.

5.2.    Insoluble Products

Dissolve 10 g of potassium hexacyanoferrate (II) in 100 ml of water. The solution should be clear.

5.3.    Preparing the Test Solution

Calcine 1 g of potassium hexacyanoferrate (II) in a silica dish, but without exceeding 550 °C.  Take up the residue with 10 ml of water and 2 ml of concentrated nitric acid (R).  Decant in a 50 ml volumetric flask.  Add 5 ml concentrated ammonium hydroxide (R). Fill to 50 ml with distilled water. Filter.

5.4.    Chlorides

To 2.5 ml of this test solution (5.3), add 5 ml nitric acid diluted to 10 pp 100 (R), 12.5 ml of distilled water and 0.5 ml of 5 pp 100 silver nitrate (R). If any opalescence develops, it should be less intense than that observed in a control prepared as indicated in the Annex.

(Chloride content, expressed in terms of hydrochloric acid content, should be less than 1 g/kg).

5.5.    Sulfates

Add 2 ml hydrochloric acid diluted to 10 pp 100 (R) to a 5 ml test solution (5.3), increase to 20 ml with distilled water and add 2 ml of a barium chloride solution (R). The mixture should be clear; or else, any opalescence observed after 15 minutes should be less intense than that of the control prepared as indicated in the annex. (Sulfates conent, as expressed for sulfuric acid, should be lower than 1 g/kg.)

5.6.    Sulfides

In the 100 ml flask of a distilling apparatus equipped with a small rectifying column or other anti-priming device (designed to prevent the direct flow of liquid fractions in the flask into the distillate), dissolve 1 g of potassium hexacyanoferrate (II) in 10 ml of  hydrochloric acid diluted to 10 pp 100 (R) and 10 ml of distilled water. Distill and collect 5 ml of distillate in 5 ml of 1M sodium hydroxide.

Take 0.5 ml of this distillate and add 18.0 ml of distilled water and 1 ml of a lead nitrate solution in a concentration of 1 g per liter (R). The resulting brown coloration should be less intense than that of a control prepared by adding 0.5 ml of hydrogen sulfide solution in a concentration of 1 g of sulfur per liter (R), 18 ml of distilled water and 1 ml of lead nitrate in a concentration of 1 g per liter (R). (Sulfide content, expressed in terms of sulfur, should be less than 100 mg/kg).

5.7.    Cyanides

In a 40 ml volumetric flask containing 25 ml of distilled water and 2.5 ml of pH 7.5 buffer solution (R), place 40 mg of potassium hexacyanoferrate (II).  After dissolving, add immediately 0.3 ml of 0.1 pp 100 T chloramine solution (R). Wait 90 seconds, then add 6 ml of pyridine-pyrazolone reagent (R).

Fill to 40 ml with distilled water and mix. The resulting coloration should not be more intense than that obtained by treating in the same way 4 ml of freshly prepared potassium cyanide solution assayed at 1 mg of hydrogen cyanide per liter (R).

(Free cyanide content, expressed in terms of hydrogen cyanide, should be less than 100 mg/kg).

5.8.    Lead

Using the technique described in the Compendium, determine the lead content in the solution (5.3). (Lead content should be less than 5 mg/kg.)

5.9.    Mercury

Using the technique described in the annex, determine the mercury content in the test solution (5.3). (Mercury content should be less than 1 mg/kg.)

5.10. Arsenic

Using the technique described in the annex, determine the arsenic content in the test solution (5.3). (Arsenic content should be less than 3 mg/kg.)

5.11. Ammonia

Place 2 g of potassium hexacyanoferrate (II), 25 ml of distilled water and 5 ml of 30 pp 100 sodium hydroxide (R) in the flask of a distilling apparatus. Distill and collect 20 ml of distillate in 40 ml of 4 pp 100 boric acid (R) in the presence of methyl red. 1.2 ml of 0.1M hydrochloric acid should be sufficient to turn the indicator.

(Total ammonia content should be less than 100 mg/kg).

  1. Storage

Potassium hexacyanoferrate (II) should be stored in airtight bags away from moisture.

Potassium D,L-tartrate

COEI-1-POTRAC Potassium D,L-Tartrate

Potassium D,L-2,3-dihydroxybutanedioate

Potassium racemate

COOK-CHOH-CHOH-COOK = 226.3

  1. Objective, origin and scope of application

Potassium D,L-tartrate is a salt used to deacidify musts and wines and to remove excess calcium.

Its use is subject to certain regulations.

  1. Labelling

The label should indicate product purity as well as its safety and storage conditions. It should also clearly state that this is a racemic mixture of the two isomers D and L of tartaric acid, thereby avoiding the supposition that it is the natural L-tartaric acid found in grapes.

  1. Properties

This product is the dipotassic salt of D,L-tartaric acid or racemic tartaric acid K2C4H4O6.

It is found in the form of white crystals or granulated white powder and is highly soluble in water.

  1. Tests

4.1.    Desiccation Loss (volatile substances)

After 4 hours of desiccation in a 105 °C oven, weight loss should not exceed 1 pp 100.

4.2.    Preparing the Solution for Tests

Place 10 g of potassium racemate in a 100 ml volumetric flask and fill to the gauge line with water.

Perform the same tests on this solution as indicated in the monograph on neutral potassium tartaric, including sodium, and observe the same limits.

4.3.    Distinguishing Potassium D,L-Tartrate from Neutral Potassium Tartrate

Proceed as indicated in the monograph on neutral potassium tartrate. No white, crystalline precipitate should form instantaneously.

4.4.    Lead

Using the technique described in the Annex, determine the lead content. Content to be less than 5 mg/kg.

4.5.    Mercury

Using the technique described in the Annex, determine the mercury content.  Content to be less than 1 mg/kg.)

4.6.    Arsenic

Using the technique described in the Annex, determine the arsenic content. Content to be less than 3 mg/kg.

4.7.    Oxalate

Using the technique described in the Annex, determine the mercury content in the test solution (4.2) (The content, expressed as oxalic acid, should be less than 100 mg/kg.)

  1. Storage

Potassium tartrate should be stored in hermetically sealed containers.

Potassium sorbate

COEI-1-POTSOR Potassium sorbate

Potassium-2,4-hexadienoate

Kalii sorbas

CH3-CH=CH-CH=CH-COOK

= 150.2

SIN No. 202

  1. Objective, origin and scope of application

This product is used as a preservative. Potassium sorbate releases 74% sorbic acid, whose anti-fungal properties inhibit the spread of yeast. Its use is limited to 200 mg/l, expressed in the form of sorbic acid.

Sorbic acid is not a bactericide. It is metabolized by certain bacteria and has a characteristic "geranium" taste.

For this reason, its presence in wine does not make it possible to remove SO2.

  1. Labelling

The label should indicate the purity of the product, its sorbic acid content and its safety and storage conditions.

  1. Centesemal composition

Sorbic acid

74.64

Potassium

26.03

  1. Solubility

Water at 20 °C

highly soluble

Alcohol, 95% by vol.

moderately soluble (14 g/l

Ethyl ether

insoluble

  1. Identifying properties

5.1.    White, water soluble powder or granules; the solution thereof is neutral when phenolphthalein (R) is added, and alkaline when adding methyl red (R).

5.2.    Stir 20 mg potassium sorbate with 1 ml brominated water (R) and 1 drop of acetic acid (R). The color should disappear.

5.3.    A solution containing 5 mg potassium sorbate per liter of water has an absorption band of 256 nm.

5.4.    A aqueous solution (concentration: 10 pp 100) precipitates using acids and exhibits the characteristics of potassium.

  1. Tests

6.1.    Solubility

Verify complete solubility in water and in alcohol.

6.2.    Desiccation Loss

1 g potassium sorbate in an oven set at 105 °C should not lose more than 1/100 of its weight in 3 hours.

6.3.    Preparing the Solution for Tests

Dissolve 1 g of potassium sorbate in 40 ml of water in a 50 ml volumetric flask. Add 0.5 ml concentrated nitric acid (R).  Fill to the gauge line with water and filter.

6.4.    Chlorides

Add 0.5 ml of nitric acid diluted to 10 pp 100 (R), 17 ml of water and 0.5 ml of 5 pp 100 silver nitrate (R) to 2.5 ml of the test solution as prepared under Paragraph 4. The resulting opalescence should be less than that of a control prepared as indicated in the Annex. (Chloride content, expressed in terms of hydrochloric acid, should be less than 1 g/kg).

6.5.    Sulfates

Add 1 ml of diluted hydrochloric acid diluted to 10 pp 100 (R), 14 ml of water and 2 ml of barium chloride solution (R) to 5 ml of the test solution as prepared under paragraph 6.4.  The mixture should be clear; or else, the opalescence observed after 15 minutes should be less than that of a control prepared as indicated in the Annex.  (Sulfate content, expressed in terms of sulfuric acid, should be less than 1 g/kg).

6.6.    Heavy Metals

Dissolve 1 g of potassium sorbate in 15 ml of water. Add 2 ml of pH 3.5 buffer solution (R) and 1.2 ml of thioacetamide reagent (R).  The mixture should remain colorless, or less intensely colored than a solution containing 1 g of the same potassium sorbate in 15 ml of water. If there is an increase in color, it should be equal to that of the control containing 20 µg of lead.  For this comparison, use the same system described for sorbic acid.  (Heavy metal content, expressed in terms of lead, should be less than 10 mg/kg).

6.7.    Lead

Using the technique described in the Compendium, determine lead content in the test solution (6.3). (Lead content should be less than 5 mg/kg).

6.8.    Mercury

Implementing the technique detailed in the Annex, determine mercury content in the test solution (6.3). Content should be less than 1 mg/kg.

6.9.    Arsenic

Implementing the technique detailed in the Annex, determine the arsenic content in the test solution (6.3). Content should be less than 3 mg/kg.

6.10. Aldehyde Determination

Add 05 ml nitric acid diluted to 10 pp 100 (R) and 14 ml water to 2.5 ml of the test solution (6.3). Add 0.5 ml fuchsin solution bleached using sulfuric acid (R) to 1 ml of this solution and, after 15 minutes, compare to a control tube obtained using 0.5 ml of the same reagent and 1 ml formaldehyde in solution in a concentration of 20 μg per milliliter. The color should be less intense than that of the control. (Aldehyde content, expressed in the form of formaldehyde, should be less than 1 g/kg.).

6.11. Quantitative Analysis

This analysis should be performed using product to be analyzed that has been previously dried in a desiccator with sulfuric acid for 24 hours.

Add a weight, p (in g) of dried product of about 0.2 g to the wash bottle of a steam distillation device, along with 1 g of tartaric acid and 10 ml of water. Distill at least 250 ml (until the steam does not entrain any more acid).  Titrate the distilled acidity with 0.1M sodium hydroxide solution; Let n be the number of ml used. 1 ml 0.1M sodium hydroxide corresponds to 0.01502 g potassium sorbate.

Potassium sorbate content in percent of the product tested:

Titration of the potassium sorbate analyzed should give at least 98 pp 100 for the dried product.

  1. Storage

Potassium sorbate should be stored in an airtight container away from light to retard oxidation.

Potassium-L(+)-tartrate

COEI-1-POTTAR Potassium-L(+)-Tartrate

Potassium-L-2,3-dihydroxybutanedioate

Dipotassium tartrate

Neutral potassium tartrate

COOK-CHOH-COOK, = 235.3

SIN No. 336 ii

  1. Objective, origin and scope of application

Dipotassium L-tartrate is used to deacidify musts and wines.  Its use is subject to the regulatory restrictions in force in certain countries.

  1. Labelling

The label should indicate product purity (greater than or equal to 98% in the product by dry weight), its safety and storage conditions, and the fact that deacidification of wine is subject to certain requirements.

  1. Properties

This is the dipotassium salt of L-tartaric acid (positive rotatory power, sometimes written as L(+) tartaric), which crystallizes with a half-molecule of water:

It is made in the form of white crystals or granulated white powder.

It is highly soluble in water.

  1. Tests

4.1.    Desiccation Loss (Volatile Substances)

After 4 hours of desiccation in a 105 °C oven, weight loss should not exceed 4 pp 100.

4.2.    Preparing the Solution for Tests

Place 10 g of neutral potassium tartrate in a 100 ml volumetric flask and fill to the gauge line with water.

Perform the same tests on this solution as indicated in the monograph on L(+) tartaric acid and observe the same limits.

4.3.    Sodium

Implementing the flame photometry technique detailed in the Compendium, determine sodium content in the test solution (4.2). (Sodium content should be less than 1 pp 100.)

4.4.    Iron

Add 1 ml concentrated hydrochloric acid (R) and 2 ml potassium thiocyanate solution (concentration: 5 pp 100) (R) to 10 ml of the test solution (4.2). The red color should not be more intense than that of the control prepared using 1 ml of an iron (III) salt solution (concentration: 0.010 g iron per liter) (R), 9 ml water, and the same quantities of the same reagents. (Content should be less than 10 mg/kg.)

The iron content may also be analyzed using the atomic absorption spectometry technique described in the Compendium.

4.5.    Lead

Applying the method set forth in the Compendium, analyze the lead content in the test solution (4.2). Lead content should be less than 5 mg/kg.)

4.6.    Mercury

Using the technique described in the Annex, determine the mercury content in the test solution (4.2). (Content to be less than 1 mg/kg.)

4.7.    Arsenic

Using the technique described in the Annex, determine the arsenic content in the test solution (4.2). (Content to be less than 3 mg/kg.)

4.8.    Distinguishing Between Potassium Tartrate and Potassium Racemate

Place 10 ml of water in a test tube with 1 ml of the test solution prepared under paragraph 4.2, 1 ml crystallizable acetic acid (R) and 2 ml of 25% calcium acetate solution (R). No white, crystalline precipitate should form instantaneously.

4.9.    Oxalate

Using the technique described in the Annex, determine the oxalate content in the test solution (4.2). (The oxalate content, expressed in terms of oxalic acid, should be less than 100 mg/kg after drying.)

  1. Storage

Potassium tartrate should be stored in hermetically sealed containers.

Protein plant origin

COEI-1-PROVEG Protein plant origin from wheat, peas and potatoes

  1. Object, origin and field of application

The plant protein matter described in this monograph is extracted from wheat (Triticum vulgaris), peas (Pisum sativum), or potatoes (Solanum tuberosum). It is mainly made up of proteins and may contain, as minority constituents, carbohydrates (fibres, starch, sugars), fats and minerals. It is intended for human consumption.

The plant protein matter is used for the fining of musts and wines.

It comes in the form of a whitish, beige or yellowish powder. It is totally or partially soluble in water depending on the pH. It can also be in liquid form with content more than or equal to 50 g/l. The solutions are stabilised with sulphur dioxide.

  1. Labelling

The following indications must appear on the label of the package: plant origin of the protein, minimal protein content, safety and storage conditions and expiry date. Without prejudice to the provisions in force in the countries where these products are marketed to be used, GMO origin of the raw material is indicated on the package label.

  1. Test trials

3.1.    Loss from desiccation

In a silica capsule with a 70 mm diameter with a lid, place 2 g of proteins. Dry in incubator at 105°C for 6 hours. Allow to cool in open capsule and desiccator. Weigh.

Weight loss must not be more than 12% of the powder preparation.

All limits set below concern dry weight.

3.2.    Determination of total nitrogen

On a 0.2 g test sample proceed as indicated in chapter II of the Oenological Codex.

The total nitrogen must be more than 10% of the powder weight (corresponding to about 65% in protein).

3.3.    Ashes

Incinerate the residue left from the determination of the loss from desiccation (3.1) by progressively heating at 600°C in a muffle oven until a white residue is obtained and after having sprinkled it with 0.2 to 0.3 g of ashes paraffin in order to avoid mass overflow.

Total ashes must be less than 8%.

3.4.    Preparation of the test trial solution

After weighing, dissolve the ashes in 2 ml of concentrated hydrochloric acid (R) and 10 ml of water. Heat in order to activate the dissolving and add distilled water until a volume equal to 25 times the weight of dry protein is obtained. 1 ml of this solution contains mineral substance of 0.04 g of dry protein.

3.5.    Iron

1 ml of concentrated hydrochloric acid (R), a drop of potassium permanganate at 1% (R) and 2 ml of potassium thiocyanate at 5% (R) were added to 10 ml of the test solution prepared according to 3.4.

If a red colouration appears, it must be lighter than the control prepared with 6 ml of iron solution (III) at 0.010 g per litre (R), 4 ml of water and the same quantities of concentrated hydrochloric acid (R) and potassium thiocyanate at 5% (R).

The iron content must be less than 150 mg/kg, with the exception of proteins from peas and potatoes, whose content should be less than 300 mg/kg.

It is also possible to proceed with the determination of iron by spectrophotometric atomic absorption according to the method described in chapter II of the International Oenological Codex.

3.6.    Chromium

In a 50 ml conical flask, place 10 ml of solution prepared according to 3.4, 1 ml of 15% (R) ammonium persulphate solution at, 0.5 ml of a 1% (R) silver nitrate solution at. Heat and add drop by drop until a persistent pink colouration appears of the 3% (R) potassium permanganate solution at. Put a few drops in excess and maintain a gentle boil for 10 minutes. If during boiling, the solution becomes discoloured, add potassium permanganate. After 10 minutes, introduce drop by drop diluted hydrochloric acid at 1/10 (R) until the solution is once again colourless.

After cooling, transfer to a 20 ml graduated flask and add 2 ml of 0.05% diphenylcarbazide in solution at in freshly prepared alcohol (R). Bring to 20 ml.

If a red purplish colouration appears, it must be lighter than that obtained by treating 4 ml of 0.001 g of chromium per litre (R) potassium dichromate solution at by 2 ml sulphuric acid at 5% (R), 5 ml of distilled water, by adding after mixing 2 ml of diphenylcarbazide solution at 0.05% in alcohol (R) and by bringing to 20 ml.

Chromium content must be less than 10 mg/kg.

It is also possible to proceed with the determination of chromium by atomic absorption according to the method described in chapter II of the International Oenological Codex.

3.7.    Copper

2.5 ml of the test trial solution prepared according to 3.4, are placed in a test tube with 7.5 ml of water, 0.5 ml of hydrochloric citric solution (R), 1 ml of ammonium hydroxide 5 M (R), 0.5 ml of sodium diethyldithiocarbamate reagent (R). If a yellow colouration appears, it must not be darker than that obtained by adding the same quantities of the same reagents to 4.7 ml of a copper solution at 1 mg per litre (R) brought to 10 ml.

Copper content must be less than 35 mg/kg.

It is also possible to proceed with the determination of copper by atomic absorption according to the method described in chapter II of the International Oenological Codex.

3.8.    Zinc

To 1.25 ml of the test solution prepared according 3.4, add 3.75 ml of distilled water, 5 ml of acetate buffer solution (R), 1 ml of sodium thiosulphate solution at 25% (m/v) (R), 5 ml of dithizone solution at 25 mg per litre in chloroform or dichloromethane (R). Shake for 2 minutes. Separate the organic phase; its colouration must be lighter than that obtained by treating 2 ml of zinc solution at 1 mg per litre (R) with the same quantities of the same reagents.

Zinc content must The zinc content must be less than 50 mg/kg, with the exception of proteins from peas, whose content should be less than or equal to 150 mg/kg.

It is also possible to proceed with the determination of zinc by atomic absorption according to the method described in chapter II of the International Oenological Codex

3.9.    Lead

Using the test trial solution (3.4), perform the determination using the method described in chapter II of the International Oenological Codex.

Lead content should be less than 5 mg/kg.

3.10. Mercury

Perform the determination of mercury using the method described in chapter II of the International oenological Codex.

Mercury content should be less than 1 mg/kg

3.11. Arsenic

Perform the determination of arsenic using the method described in chapter II of the International oenological Codex.

Arsenic content should be less than 3 mg/kg.

 

3.12. Cadmium

Perform the determination of cadmium using the method described in chapter II of the International Oenological Codex.

Cadmium content should be less than 1 mg/kg.

 

  1. Microbiological control

4.1.    Total viable micro-organisms

Proceed as described in Chapter II of the International Oenological Codex.

Content less than 5.104 CFU/g.

4.2.    Escherichia coli

Proceed with counting as described in Chapter II of the International Oenological Codex.

Absence checked on a 1 g sample.

4.3.    Salmonella

Proceed with counting as described in Chapter II of the International Oenological Codex.

Absence checked on a 25 g sample.

4.4.    Coliforms

Process with counting as described in Chapter II of the International Oenological Codex.

Content less than 102 CFU/g.

4.5.    Yeasts

Proceed with counting as described in Chapter II of the International Oenological Codex.

Content less than 103 CFU/g.

4.6.    Moulds

Proceed with counting as described in Chapter II of the International Oenological Codex.

Content less than 103 CFU/g.

  1. Search for mycotoxins and pesticide residues

5.1.    Aflatoxins B1

Proceed with analysis according to ISO method 16050

Content less than 4 μg/kg.

5.2.    Aflatoxin B1, B2, G1, G2

Proceed with analysis according to ISO method 16050

Content less than 4 μg/kg in total.

5.3.    Organophosphorous pesticide residues [1]

Content less than 10 mg/kg.

5.4.    Organochlorine pesticide residues[2]

Content less than 0.1 mg/kg.

5.5.    Ochratoxine A

Using an aqueous solution of 5 g/l of plant protein, perform the determination using the method described in the Compendium of methods of analysis of musts and wines.

Content less than 5 μg/kg.

  1. Reasearch specific for solanum teberosum

6.1.    Glycoalkaloids (- solanine & - chaconine)

Proceed with analysis according to AOAC method 997.13

Maximum content less than 300 mg/kg of potatoes protein

  1. Storage

The plant proteins should be stored in closed containers or in watertight bags impervious to humidity under temperate conditions.


[1] Method to be determined at a later date

[2] Method to be determined at a later date

Polyvinylimidazole/Polyvinylpyrrolidone

COEI-1-PVIPVP Adsorbent copolymers of polyvinylimidazole/ Polyvinylpyrrolidone (PVI/PVP)

N° CAS: 87865-40-5

  1. Object, origin and scope of application

Adsorbent copolymers of PVI/PVP are insoluble and slightly-hygroscopic powders. They are manufactured by "popcorn" polymerization of N-vinylimidazole (CAS no. 1072-63-5,) and N-vinyl-2-pyrrolidone (CAS no. 88-12-0,), with a ratio of 9:1.  N,N´-divinylimidazolidin-2-one (CAS no. 13811-50,) is used as crosslinking agent at a level of less than 2% by weight of the total amount of the monomers.

Adsorbent copolymers of PVI/PVP are added to must or wine in accordance with the files described in the Code of Oenological Practices of the OIV in amounts of less than 500 mg/l.

Adsorbent copolymers of PVI/PVP can be added to must or wine in order to prevent the defects caused by excessive metal contents or to reduce undesirably-high metal concentrations.

The must or wine must be filtered through a filter media with pores whose diameter is no greater than 3 microns and with a filtration pressure no greater than 0.8 bars.

  1. Synonyms

Terpolymer of 1-vinylimidazole, 1-vinylpyrrolidone, and 1,3-divinylimidazolidinone.

Cross-linked copolymer of vinylimidazole/vinylpyrrolidone.

  1. Labelling

The labelling must indicate that the PVI/PVP adsorbing copolymer is for oenological use. The storage and safety conditions must also be indicated.

The label must mention a 3-year use-by date.

  1. Characters

 

Powder with a white to yellowish colour.

PVI/PVP adsorbing copolymers are insoluble in practically all current solvents. It is therefore impossible to measure the molecular weight.

  1. Tests

5.1.    Loss on desiccation

Tare a metal capsule 50 mm in diameter. Place in the recipient between 0.8 and 1.4 g of PVI/PVP adsorbent copolymer, homogenised beforehand and weighed preciselyin a closed balance. Dry in a drying oven at 140°C ± 5°C for 1 hour. Allow to cool in a desiccator. Weigh again.

The loss on desiccation must be less than 5 %.

5.2.    Ash

Heat a porcelain crucible until it is dark red; allow to cool in a desiccator and weigh. Place 1.5 g of PVI/PVP adsorbent copolymer in the crucible and incinerate at a constant weight in a muffle furnace at 800°C ± 25°C, allowing the crucible to cool in a desiccator after each incineration, the duration of the first incineration being 6 hours. If necessary, pre-incinerate the sample.

The weight of the ash must be less than 0.02 %.

5.3.    Preparation of the solution for tests:

After weighing the ash, dissolve it in 1 ml of concentrated hydrochloric acid (R) and 10 ml of distilled water. Heat to activate dissolution. Make up to 20 ml with distilled water. 1 ml of this solution contains the mineral matter of 0.075 g of PVI/PVP adsorbent copolymer.

5.4.    Zinc

Using the solution for tests prepared as in point 5.3, measure zinc according to the method described in Chapter II.

The zinc content must be less than 1 mg/kg.

5.5.    Iron

Using the solution for tests prepared as in point 5.3, measure iron according to the method described in Chapter II.

The iron content must be less than 5 mg/kg.

5.6.    Copper

Using the solution for tests prepared as in point 5.3, measure copper according to the method described in Chapter II.

The copper content must be less than 1 mg/kg.

5.7.    Lead

Using the solution for tests prepared as in point 5.3, measure lead according to the method described in Chapter II.

The lead content must be less than 2 mg/kg.

5.8.    Cadmium

Using the solution for tests prepared as in point 5.3, measure cadmium according to the method described in Chapter II.

The cadmium content must be less than 1 mg/kg.

5.9.    Arsenic

Do not use the solution for tests prepared as in point 5.3.

Determine the arsenic according to the method described in Chapter II.

The arsenic content must be less than 2 mg/kg.

5.10. Mercury

Do not use the solution for tests prepared as in point 5.3.

Determine the mercury according to the method described in Chapter II.

The mercury content must be less than 1 mg/kg.

5.11. Organic impurities

Determine the organic impurities according to the method described in Appendix 1.

The limits of organic impurities must be as follows:

  • The vinylpyrrolidone content must be less than 5 mg/kg
  • The vinylimidazole content must be less than 10 mg/kg
  • The divinylimidazolidinone content must be less than 2 mg/kg
  • The pyrrolidone content must be less than 50 mg/kg
  • The imidazole content must be less than 50 mg/kg

5.12. Measurement of total nitrogen

Place approximately 450 mg of PVI/PVP adsorbing copolymer (test portion m mg) in a mineralisation flask, add 10 g of Missouri Catalyst[1], and 3 glass beads. Wash all the particles that adhere to the neck of the flask with a small quantity of sulphuric acid (R). Add in total 20 ml of sulphuric acid (R), running it along the walls of the flask, and mix the contents by rotation. Continue the analysis according to the method described in Chapter II.

The total nitrogen content must lie between 26.0 and 29.0% with respect to the dry weight.

5.13. Solubility in an aqueous medium

Place 10 g of PVI/PVP adsorbent copolymer in a graduated 200-ml flask containing 100 ml of water. Shake the bottle and allow the contents to rest for 24 hours. Filter on a filter membrane with 2.5 μm diameter pores, and then on a filter membrane with 0.8 μm diameter pores. The dry residue remaining after evaporation of the filtrate on a water bath must be less than 0.5%.

5.14. Solubility in acid and alcohol

Introduce 1 g of PVI/PVP adsorbent copolymer into a bottle containing 500 ml of the following mixture:

Acetic acid

3 g

Ethanol

10 ml

Water

100 ml

Allow to rest for 24 hours. Filter on a filter membrane with 2.5 μm diameter pores, then on a filter membrane with 0.8 μm diameter pores. Concentrate the filtrate on a water bath. Finish the evaporation on a water bath in a calibrated silica capsule 70mm in diameter. The dry residue remaining after evaporation must be less than 1%, taking into account all the residue of the evaporation of the 500 ml of the mixture of acetic acid, ethanol and water.

5.15. Determination and content of monomers in musts and wines

5.15.1.     Analytical method

Proceed with the determination according to the analytical method in Appendix 2

5.15.2.     Limits of monomers in musts and wines[2]

  • The vinylpyrrolidone content must be less than 10 μg/l
  • The vinylimidazole content must be less than 10 μg/l
  • The pyrrolidone content must be less than 25 μg/l
  • The imidazole content must be less than 150 μg/l
  1. Storage

The PVI/PVP adsorbing copolymer must be kept in a cool place. The recipients must be dry and hermetically sealed.

Appendix 1 Determination by gas chromatography of the constitutive monomers

and/or impurities liable to be found in  copolymers of vinylpyrrolidone-vinylimidazole (vinylimidazole, vinylpyrrolidone, pyrrolidone, divinylethyleneurea and imidazole)

  1. Principle

Detection and determination of the constitutive monomers and/or impurities liable to be found in copolymers of vinylpyrrolidone-vinylimidazole (vinylimidazole, vinylpyrrolidone, pyrrolidone, divinylethyleneurea and imidazole).

The analysis is carried out by capillary gas chromatography using a nitrogen specific detector (NSD). The substances to be analysed are extracted beforehand from the polymer by acetone.

  1. Range of contents to be determined

Vinylimidazole

2-55 μg/g

Vinylpyrrolidone

2-50 μg/g

Pyrrolidone

2-70 μg/g

Divinylethyleneurea

2-33 μg/g

Imidazole

2-50 μg/g

  1. Reagents and reference material

 

3.1.    Vinylpyrrolidone-vinylimidazole copolymers;

3.2.    Vinylimidazole, M(C5H6N2) = 94.12 g/mol

purity > 99% (GC), e.g. Fluka, item no. 95005

(R: 22-34, S: 26-36/37/39-45)

3.3.    Vinylpyrrolidone (1-vinyl-2-pyrrolidone), M(C6H9NO) = 111.14 g/mol

purity = 99.8% (GC), e.g. Fluka, item no. 95060

(R: 20/21/22-36/37/38-40, S: 26-36/37/39)

3.4.    Pyrrolidone, (2-pyrrolidone), M(C4H7NO) = 85.11 g/mol

purity > 99% (GC), e.g. Fluka, item no. 83300

(R: 36/37/38, S: 26-36)

3.5.    Divinylethyleneurea (N,N-divinylimidazolidone), M(C7H10N2O) = 138.17 g/mol

purity ≥ 99% (GC), BASF reference material

(R: 36/38-40, S: 26-36/37)

3.6.    Imidazole, (C3H4N2) = 68.08 g/mol

purity > 99.5% (GC), e.g. Fluka, item no. 56748

(R: 22-34, S: 26-36/37/39-45)

3.7.    Benzonitrile,

purity > 99% (G), e.g. Merck-Schuchardt, item no. 801800

(R: 10-35, S: 23-26-45)

3.8.    Acetone,

purity ≥ 99% (GC), e.g. Fluka, item no. 00585

(R: 11, S: 9-16-23-33)
 

  1. Apparatus

 

4.1.    Capillary gas chromatograph with an automatic sampler, split injector, nitrogen specific detector (NSD).

4.2.    Fused silica capillary column, with a polyethylene glycol film, (e.g. DB-Wax, J&W Scientific)

  • Length: 30 m
  • Internal diameter: 0.25 mm
  • Film thickness: 0.5 μm
    1.     Data acquisition and processing system
    2.     Analytical balance accurate to 0.1 mg
    3.     Laboratory glassware and standard apparatus
    4.     Rotary mixer capable of housing small-capacity flasks, e.g. 50 ml.
  1. Solutions

5.1.    Internal standard solution

Benzonitrile, 250 µg/ml in acetone (3.8)

5.2.    Stock calibration solution

Prepare a stock calibration solution of different concentrations in acetone (3.8) containing vinylimidazole, vinylpyrrolidone, pyrrolidone, divinylethyleneurea and imidazole with amounts ranging from 250 mg/l to 1000 mg/l.

5.3.    Calibration solutions

Prepare at least two calibration solutions with different concentrations in acetone (3.8). Each solution must contain a suitable quantity of the internal standard as well as vinylimidazole, vinylpyrrolidone, pyrrolidone, divinylethyleneurea and imidazole so that the calibration points include the values currently being measured.

Example: 4 µl-200 μl of stock solution (5.2) + 24 ml of acetone (3.8) + 1 ml of internal standard solution (5.1).

  1. Example of chromatographic conditions

 

Temperatures:

Injector: 220°C

Oven: 160°C

  • then programmed at a rate of 5°C/min up to 210°C

Final isothermal period: 210°C, 7 min

Detector (NSD): 250°C

Carrier gas

helium

Column head pressure

140 kPa (1.4 bar)

Split flow

10 ml/min

Septum purge

5 ml/min

Volume injected

1.0 μl

  1. Preliminary check of the analytical system

7.1.    Resolution

Prepare a solution of benzonitrile and vinylimidazole (10 and 2 μg/ml in acetone).

Inject this solution into the chromatograph under the conditions described in 6.

The analysis is considered satisfactory when the resolution of the two chromatographic peaks is at least 1.5 (R > 1.5), with a return to the baseline between the two peaks.

7.2.    Sensitivity

To check the sensitivity:

1) Carry out a preliminary analysis of a sample (8.1) under the conditions described in section 6.

2) Add to the sample 2 μg/g divinylethyleneurea then repeat the analysis under the conditions described in section 6.

If the sample does not contain divinylethyleneurea the system is suitable when the peak of added divinylethyleneurea presents a signal-to-noise ratio of at least 10.

If the sample contained divinylethyleneurea a clear increase in the signal should be observed.

  1. Procedure

8.1.    Preparation of the samples

Weigh about 2g of sample, accurate to 0.1 mg, then mix it with 1 ml of internal standard solution (5.1) and 24 ml of acetone (3.8). Extract the sample for 4 h on the rotary mixer (4.6) then analyse the supernatant solution under the conditions described in point 6.

For routine determinations, analyse each sample twice.

8.2.    Chromatograms

Extracted by acetone from a copolymer (fig. 1)

Extracted by acetone from a copolymer supplemented with analytes (fig. 2)

  1. Calculation

9.1.    Calibration factor

Chromatographic calibration factor f(i):

where:

  • A(i)0 = peak area of analyte  i in the chromatogram for the calibration solution (mVs)
  • m(i)0 = initial weight of reference product i in the calibration solution [mg]
  • A(I.S.) 0 = peak area of the internal standard in the chromatogram of the calibration solution (mVs)
  • m(I.S.) 0 = initial weight of the internal standard in the calibration solution [mg]

The weight ratio w(i) of analyte i is calculated in the following way:

where:

  • w(i) = weight ratio of the analyte i [µg/g]
  • A(i)= peak area of the analyte I in the chromatogram of the sample solution (mVs)
  • A(I.S.)= peak area of the internal standard in the chromatogram of the sample solution (mVs)
  • m(I.S.)= initial weight of the internal standard added to the sample [µg]
  • m(s) = initial weight of sample [g]
  • f’(i) = average chromatographic calibration factor

For routine determinations, the result is expressed as a whole number.

  1. Characteristics of the method

10.1. Specificity, selectivity

In the chromatogram, the peaks are identified according to their retention time in comparison with the retention time of the solutions of pure analytes (3.2 to 3.6) injected under the same conditions.

Check that the components of the sample have a retention time different from that of the internal standard and that the resolution between peaks is always greater than 1.5.

10.2. Linearity

During calibration, the calibration factors were determined at 6 levels of concentration for each analyte. The calibration curves are straight lines (cf. fig. 3-7) with the following coefficients of determination:

Vinylimidazole

R² = 0.9987

Vinylpyrrolidone

R² = 0.9999

Pyrrolidone

R² = 0.9956

Divinylethyleneurea

R² = 0.9937

Imidazole

R² = 0.9982

10.3. Limit of quantification

The calibration measurements were used to determine the following limits of quantification:

Vinylimidazole

2 μg/g

Vinylpyrrolidone

2 μg/g

Pyrrolidone

2 μg/g

Divinylethyleneurea

2 μg/g

Imidazole

2 μg/g

10.4. Precision

To determine the precision under repeatability conditions, a copolymer sample was analysed 6 times: (Table 1)

Table 1

 

   

Vinylimidazole

Vinylpyrroli

done

Pyrrolidone

Divinylethyleneurea

Imidazole

1. Determination

[μg/g]

nq*

nd**

4.1

nd

10.7

2. Determination

[μg/g]

nq

nd

4.3

nd

10.8

3. Determination

[μg/g]

nq

nd

4.2

nd

11.5

4. Determination

[μg/g]

nq

nd

4.3

nd

11.8

5. Determination

[μg/g]

nq

nd

3.9

nd

10.2

6. Determination

[μg/g]

nq

nd

3.9

nd

10.8

Average

[μg/g]

nq

nd

4.1

nd

11.0

Standard deviation

[μg/g]

   

0.2

 

0.6

Coeff. of variation

%

   

4.8

 

5.1

Measurement uncertainty

[μg/g]

   

0.6

 

1.7

Relative measurement uncertainty

%

   

14

 

15

*nq = not quantifiable

**nd= not detectable

In the sample, the vinylpyrrolidone and divinylethyleneurea could not be detected and the vinylimidazole could not be quantified.

10.4.1.     Repeatability

The copolymer sample was supplemented with all the analytes then analysed 6 times. The accuracy under repeatability conditions can be deduced from the repeatability for vinylpyrrolidone, divinylethyleneurea and vinylimidazole. (Table 2)

Table 2

   

Vinylimidazole

Vinylpyrrolidone

Pyrrolidone

Divinylethyleneurea

Imidazole

1. Determination

[%]

102.3

112.4

97.0

103.3

90.7

2. Determination

[%]

98.5

101.9

89.6

102.1

91.7

3. Determination

[%]

111.8*

111.5

105.7

111.1

112.6*

4. Determination

[%]

102.7

103.3

91.9

104.8

94.5

5. Determination

[%]

104.2

101.0

89.3

102.7

97.0

6. Determination

[%]

100.4

104.9

90.4

110.3

95.4

Average

[%]

101.6

105.8

94.0

105.7

93.9

             

Standard deviation

[%]

2.2

4.9

6.4

3.9

2.6

Coeff. of variation

[%]

2.2

4.7

6.8

3.7

2.8

Measurement uncertainty

[%]

6.6

14.8

19.2

11.8

7.8

Relative measurement uncertainty

[%]

7

14

20

11

8

*= outlier value according to the Dixon test

10.5. Addition recovery

The recovery can be calculated from table 2.

Vinylimidazole

101.6 %

Vinylpyrrolidone

105.8 %

Pyrrolidone

94.0 %

Divinylethyleneurea

105.7 %

Imidazole

93.9 %

Note

Applicability to other copolymers of vinylpyrrolidone-vinylimidazole

The method was validated for Divergan HM. In principle, we can consider the determination is also valid for other copolymers of vinylpyrrolidone-vinylimidazole.

Fig. 1: Chromatogram of the copolymer extract (with internal standard)

 

Une image contenant texte

Description générée automatiquement

   

Fig. 2 Chromatogram of the copolymer extract (with internal standard),

supplemented by 2.1 µg/g of vinylimidazole, 2.1 μg/g of vinylpyrrolidone, 3.9 μg/g of pyrrolidone, 2.1 µg/g of divinylethyleneurea, and 12.7 µg/g of imidazole.

Fig. 3: calibration line for vinylimidazole

Analyte peak area*test sample (int. std.)

Peak area (int. std.) [mg]

Analyte test sample related to standard test sample [µg/g]

Fig. 4: calibration line for vinylpyrrolidone

Analyte peak area*test sample (int. std.)

Peak area (int. std.) [mg]

Analyte test sample related to standard test sample [µg/g]

Fig. 5: calibration line for pyrrolidone

Analyte peak area*test sample (int. std.)

Peak area (int. std.) [mg]

Analyte test sample related to standard test sample [µg/g]

 

Fig. 6: calibration line for divinylethyleneurea

Analyte peak area*test sample (int. std.)

Peak area (int. std.) [mg]

Analyte test sample related to standard test sample [µg/g]

Fig. 7: calibration line for imidazole

Analyte peak area*test sample (int. std.)

Peak area (int. std.) [mg]

Analyte test sample related to standard test sample [µg/g]

Appendix 2:Analytical method for the detection of Imidazole, Pyrrolidone and residual monomers (Vinylpyrrolidone, Vinylimidazole, Divinylimidazolidinone) in wines and musts

 

  1. Scope

The method described here is suitable for the determination of Imidazole, Pyrrolidone, Vinylimidazole and Vinylpyrrolidone in white, red, sweet and dry wines, and must.

Divinylimidazolidinone has a half-life of 3.75 min at pH-value of 3.7. Thus determination is not appropriate in wine and must.

The study described covers the concentration ranges of 5 to 125 μg/l for Imidazole, 25 to 250 μg/l for Pyrrolidone, 2 to 25 μg/l for Vinylimidazole and 2 to 12.5 μg/l for Vinylpyrrolidone.

  1. Definitions

HPLC:High performance liquid chromatography

LC-MC:Liquid Chromatography – Mass spectrometry

MRM:multiple-reaction monitoring

  1. Principle

Samples are analyzed directly by LC-MS on a reversed-phase column (C18). Detection is then carried out in multiple-reaction monitoring mode.

  1. Reagents and Materials

4.1.    Chemicals

4.1.1.  Methanol (LiChrosolov) (CAS: 67-56-1) quality for CL-SM

4.1.2.  Bidistilled water

4.1.3.  Heptafluorobutyric acid, puriss., ≥99,5% (CAS: 375-22-4)

4.2.    Preparation of eluentS

4.2.1.  Solvent A:

  • Pipette 0.6 ml of heptafluorobutyric acid (4.1.3) into 1000 ml bidistilled water (4.1.2), shake and degas.
    1.   Solvent B:
  • Add 300 ml of bidistilled water (4.1.2) to 700 ml of methanol (4.1.1) and shake. Pipette 0.6 ml of heptafluorobutyric acid (4.1.3) into this solution, shake and degas.
    1.     Standards
      1.   Imidazole, ≥99,5 % (CAS: 288-32-4)
      2.   Pyrrolidone, ≥99 % (CAS: 616-45-5)
      3.   Vinylimidazole, ≥99 % (CAS: 1072-63-5)
      4.   Vinylpyrrolidone, =99,8 % (CAS: 88-12-0)
    2.     Preparation of standard solutions
      1.   Preparation of the stock standard solutions (1,00 g/l):

Weigh exactly 100 mg of standards (4.3.1-4.3.4), transfer them without loss into a 100 ml volumetric flask, fill with bidistilled water (4.1.2) to about 90 ml, shake and adjust to 100 ml.

4.4.2.  Preparation of the mixed standard solution (Imidazole: 62.5 mg/l; Pyrrolidone: 62.5 mg/l; Vinylimidazole: 12.5 mg/l; Vinylpyrrolidone: 6.25 mg/l):

Pipette 6.25 ml of the Imidazole stock solution (4.4.1), 6.25 ml of the Pyrrolidone stock solution (4.4.1), 1.25 ml of the Vinylimidazole stock solution (4.4.1) and 0.625 ml of the Vinylpyrrolidone stock solution (4.4.1) to a 100 ml volumetric flask, fill with bidistilled water (4.1.2) to about 90 ml, shake and adjust to 100 ml.

4.4.3.  Preparation of the working standard solution:

Pipette 40 µl mixed standard solution (4.4.2) to a 25-ml volumetric flask, fill with bidistilled water to 25 ml and shake.

4.5.    Preparation of the matrix calibration curve

Matrix-matched calibration solutions are prepared in an uncontaminated wine or must. Dilute the mixed standard solution (4.4.2) appropriately with the sample to give five working standards.

Calibration standards must be prepared just before measurement!

end volume

mixed standard

Imidazole

Pyrrolidone

Vinylimidazole

Vinylpyrrolidone

25 ml

0 μl

0 μg/l

0 μg/l

0 μg/l

0 μg/l

25 ml

10 μl

25 μg/l

25 μg/l

5 μg/l

2.5 μg/l

25 ml

20 μl

50 μg/l

50 μg/l

10 μg/l

5 μg/l

25 ml

30 μl

75 μg/l

75 μg/l

15 μg/l

7.5 μg/l

25 ml

40 μl

100 μg/l

100 μg/l

20 μg/l

10 μg/l

25 ml

50 μl

125 μg/l

125 μg/l

25 μg/l

12.5 μg/l

  1. Apparatus
    1.     Analytical balance accurate to 0.1mg
    2.     Assorted precision pipettes and volumetric flasks
    3.     HPLC vials (4 ml)
    4.     High-performance liquid chromatograph with mass spectrometric detector (Applied Biosystems API 4000 or equivalent)
    5.     Knauer Eurospher 100-5 C18 column with an integrated pre-column or equivalent
    6.     Internal diameter: 4.6 mm
    7.     Length: 250 mm
    8.     Stationary Phase: C18, pore size: 100 Å, particle size: 5 μm, end-capped
  1. Sample preparation

6.1.    Model wine Solution

The model wine solution is prepared according to Martínez-Rodríguez and Polo, 2000 (Characterization of the Nitrogen Compounds Released during Yeast Autolysis in a Model Wine System).

Four grams of tartaric acid, 0.1 g of acetic acid, and 120 mL of ethanol are dissolved in 800 mL of water (bidistilled). After adjustment of the pH value to 3.2 with 2N sodium hydroxide, the solution is made up to 1000 mL. The model wine solution is brought to temperature at 20°C.

 

6.2.    Sample preparation for migration analysis

The amount of 0.5 grams Divergan HM are added to 1 litre of model wine solution and stirred at 20°C for 48 hours (at approximately 150 rpm).

Prior to analysis the sample is centrifuged (approximately 3 min, 4500 rpm) and filtered through a 0.45 μm membrane filter.

 

6.3.    Other samples (e.g. musts and wines)

Clear samples are filled directly into sample vials and ready for chromatography without any sample preparation. Cloudy wine samples are filtered through a 0.45 μm membrane filter before injection, and the first fractions of filtrate are discarded.

  1. LC-MS Analysis
    1.     Operating conditions for HPLC:

Injection volume: 10 μl

Flow rate: 1 ml/min

Gradient:

Column heater: 25 °C

Run time: 45 min

7.2.    MS conditions:

 

Mass spectrometer

Applied Biosystems API 4000 or equivalent

Scan Type

MRM

Polarity

Positive

Ion Source

Turbo Spray

Duration

20,005 min; 1364 Cycles

Curtain Gas

40 psi

Ionspray Voltage

2500 V

Temperature

550°C

Ion Source Gas 1

60 psi

Ion Source Gas 2:

60 psi

Collision Gas

Medium

Entrance Potential

10 V

Collar 2

0

compound

Q1 Mass (amu)

Q3 mass (amu)

Dwell (msec)

Parameter

Start

Stop

Imidazole

69.08

42.20

75.00

DP

81.00

81.00

CE

31.00

31.00

CXP

2.00

2.00

Pyrrolidone

86.10

44.10

75.00

DP

66.00

66.00

CE

31.00

31.00

CXP

6.00

6.00

86.10

69.00

75.00

DP

66.00

66.00

CE

23.00

23.00

CXP

4.00

4.00

Vinylimidazole

95.09

41.10

75.00

DP

71.00

71.00

CE

33.00

33.00

CXP

0.00

0.00

95.09

69.20

75.00

DP

71.00

71.00

CE

29.00

29.00

CXP

12.00

12.00

Vinylpyrrolidone

112.08

69.20

75.00

DP

51.00

51.00

CE

21.00

21.00

CXP

4.00

4.00

112.08

84.00

75.00

DP

51.00

51.00

CE

17.00

17.00

CXP

14.00

14.00

DP

Declustering Potential (in volts)

CE

Collision Energy (in volts)

CXP

Collision Cell Exit Potential (in volts)

  1. Evaluation
    1.     Identification:

Inject 10 μl of working standard solution (4.4.3) to ascertain the retention times. Approximate retention times are:

compound

retention time

Imidazole

7.45 min

Pyrrolidone

8.37 min

Vinylimidazole

14.43 min

Vinylpyrrolidone

17.64 min

8.2.    Quantification:

Mass transfers for quantification:

 

compound

mass transfer

Imidazole

69.1 → 42.2

Pyrrolidone

86.1 → 44.1

Vinylimidazole

95.1 → 69.2

Vinylpyrrolidone

112.1 → 69.2  

Use the standard addition method for quantification.

8.3.    Expression of results

Results should be expressed in μg/l for Imidazole, Pyrrolidone, Vinylimidazole and Vinylpyrrolidone with no decimals (e.g. 3 μg/l).

8.4.    Limit of detection and limit of quantification

The limit of detection (LOD) and the limit of quantification (LOQ) depend on the individual measurement conditions of the chemical analysis and are to be determined by the user of the method.

The limit of detection (LOD) and the limit of quantification were estimated using the instrumentation and conditions mentioned as an example above (section 7) following the instructions in the resolution OENO 7-2000 (E-AS1-10-LIMDET) “Estimation of the Detection and Quantification Limits of a Method of Analysis“. Following the "Logic Diagram for Decision-Making" in point 3 the "graph" approach should be applied following paragraph 4.2.1. For this purpose a window is drawn on the multiple reaction monitoring chromatogram, enclosing the range of a tenfold peak width at mid-height (w½) either side at the retention time of an analyte peak in the relevant part of the chromatogram. Two parallel lines are then drawn which just enclose the maximum amplitude of the signal window. The separation between these two lines gives hmax, expressed in abundance units, which is multiplied by 3 for LOD, by 10 for LOQ, and finally converted into concentration units by implementing the individual response factor.

compound

limit of detection (LOD)

limit of quantification (LOQ)

Imidazole

5 μg/l

12 μg/l

Pyrrolidone

25 μg/l

83 μg/l

Vinylimidazole

2 μg/l

6 μg/l

Vinylpyrrolidone

2 μg/l

6 μg/l

     
  1. Precision and trueness

 

As matrices three different wines (dry white wine, dry red wine and sweet red wine) and grape juice were used. Within-laboratory reproducibility, repeatability and recovery were calculated based on matrix calibration and three spikes (Imidazole: 40/60/80 μg/l; 2-Pyrrolidone: 40/60/80 μg/l; Vinylimidazole: 8/12/16 μg/l; Vinylpyrrolidone: 4/6/8 μg/l).

9.1.    Imidazole

 

fortification

mean of series

standard deviation

corresponding CV

Horwitz RSD %

within-laboratory reproducibility (SDwlR):

40 μg/l

41

 

2

5

%

26

60 μg/l

61

 

3

5

%

24

80 μg/l

80

 

5

6

%

23

repeatability (SDr):

40 μg/l

41

 

1

2

%

 

60 μg/l

61

 

2

3

%

 

80 μg/l

80

 

4

5

%

 

recovery (WDF):

40 μg/l

102

%

       

60 μg/l

101

%

       

80 μg/l

101

%

       

0

101

%

       

Pyrrolidone

 

fortification

mean of series

standard deviation

corresponding CV

Horwitz RSD %

within-laboratory reproducibility (SDwlR):

40 μg/l

42

 

9

22

%

26

60 μg/l

60

 

9

15

%

24

80 μg/l

81

 

9

11

%

23

repeatability (SDr):

40 μg/l

42

 

5

12

%

 

60 μg/l

60

 

4

7

%

 

80 μg/l

81

 

8

9

%

 

recovery (WDF):

40 μg/l

105

%

       

60 μg/l

100

%

       

80 μg/l

101

%

       

0

102

%

       

9.2.    Vinylimidazole

 

fortification

mean of series

standard deviation

corresponding CV

Horwitz RSD %

within-laboratory reproducibility (SDwlR):

8 μg/l

8

 

0

4

%

33

12 μg/l

12

 

1

5

%

31

16 μg/l

16

 

1

4

%

30

repeatability (SDr):

8 μg/l

8

 

0

4

%

 

12 μg/l

12

 

0

3

%

 

16 μg/l

16

 

0

3

%

 

recovery (WDF):

8 μg/l

101

%

       

12 μg/l

102

%

       

16 μg/l

102

%

       

0

102

%

       

9.3.    Vinylpyrrolidone

 

fortification

mean of series

standard deviation

corresponding CV

Horwitz RSD %

within-laboratory reproducibility (SDwlR):

4 μg/l

3

 

1

31

%

37

6 μg/l

4

 

1

26

%

35

8 μg/l

5

 

2

29

%

33

repeatability (SDr):

4 μg/l

3

 

1

25

%

 

6 μg/l

4

 

1

22

%

 

8 μg/l

5

 

1

26

%

 

recovery (WDF):

4 μg/l

66

%

       

6 μg/l

63

%

       

8 μg/l

66

%

       

0

65

%

       

[1]
  Missouri Catalyst (= 49.9% K2SO4 + 49.8% Na2SO4 + 0.3% CuSO4), Merck, Darmstadt or the equivalent

[2]  The calculation of the upper limits was based on the results obtained from the migration tests with the recommended dosage of 0,5 g/l, the maximum application time of 48 hours, and a treatment temperature of 20 °C, multiplied by a factor of 2.

  Under acidic conditions (at lower pH-values) divinylimidazolidinone (divinylethylene-urea) is not stable and hence degrades to imidazolidinone and vinyl alcohol. Furthermore imidazolidinone degrades to urea and ethylene glycol. Vinyl alcohol is in chemical equilibrium with acetaldehyde.

  Imidazolidinone was included in the toxicological assessment as well as acetaldehyde, urea and ethylene glycol.

Polyvinylpolypyrrolidone

COEI-1-PVPP Polyvinylpolypyrrolidone

Povidone

(PVPP)

(

INS N° :1202

  1. Objet, origin and field of application

Insoluble polyvinylpolypyrrolidone is a polymer poly[1-(2-oxo-1-pyrrolidinylethylene] reticulated to render it insoluble. It is made by polymerisation of N-vinyl-2-pyrrolidone in the presence of different catalysers (for example sodium hydroxide) or in the presence of N'N-divinylimidazolidone.

PVPP fixes the polyphenols in wines; this adsorption depends on the rate of polymerisation. Its application rate is limited.

  1. Synonyms
  • poly(1-ethenylpyrrolidin-2-one)
  • Crospovidone (nomenclature of pharmacope)
  • Reticulated polyvidone
  • Reticulated homopolymer of 1-ethenyl-2-pyrrolidone
  • Reticulated insoluble polymer of N-vinyl-2-pyrrolidone
  • P.V.P. insoluble
  • Polyvinylpolypyrrolidone (PVPP).
  1. Labelling

The label must indicate that PVPP is for oenological usage, minimum guaranteed efficiency vis-à-vis safety test and storage conditions.

  1. Characteristics

Light powder, white and creamy white.

Insoluble in water and in organic solvents.

Insoluble in strong acid minerals and in alkaly.

  1. Test trials

5.1.    Loss through drying

Place 2 g of PVPP in a 70 mm diameter silica capsule; dry in an incubator at 100-105° C for 6 hours. Let cool in the desiccators. Weigh. Weight loss must be less than 5%.

It is also possible to carry this out more quickly by titration with the Karl-Fischer procedure (see annex).

Note: All limits set above refer to the dried product.

5.2.    Ashes

Incinerate the residue left over in test trial 5.1 progressively without going over 600° C. (Ash mass should be less than 0.5%).

5.3.    Preparation for test trial solution

After weighing the ashes, dissolve 1 ml of concentrated hydrochloric acid (R) and 10 ml of distilled water. Heat to activate the solution. Bring up to 20 ml with distilled water. 1 ml of this solution contains 0,10 g of PVPP mineral matter.

5.4.    Heavy metals

10 ml of solution prepared according to point 5.3 is put in a test tube with 2 ml of a pH 3.5 (R) buffer solution and 1.2 ml of reactive thioacetamide (R). There should be no precipitation. If a brown colour appears, it should be inferior to the test sample as indicated in Chapter II (Heavy metal content, expressed in lead, must be less than 10 mg/kg).

5.5.    Lead

Using the solution prepared idem, determine the lead, following the procedure in Chapter II or by atomic absorption spectrophotometer procedure. Lead content must be below 2 mg/kg.

5.6.    Mercury

Determine the mercury, following the procedure in Chapter II. Mercury content must be below 1 mg/kg.

5.7.    Zinc

Determine the zinc, following the procedure described in Chapter II. Zinc content must be below 5 mg/kg.

5.8.    Arsenic

Determine the arsenic, following the procedure in Chapter II. Arsenic content must be below 3 mg/kg.

5.9.    Cadmium

Determine the cadmium using the method described in Chapter II of the International oenological Codex by atomic absorption spectrophotometer procedure.

Cadmium content must be below 1 mg/kg.

5.10. Sulphates

Determine the sulphates, following the procedure in Chapter II. Sulphate content must be below 1 g/kg.

5.11. Determining total nitrogen

Introduce approximately 0.20 g of PVPP weighed precisely in a 300 ml flask with 15 ml concentrated sulphuric acid (R) and 2 g of mineralisation catalyst (R) and continue the operation as indicated in Chapter II. (Total nitrogen content must be between 11 and 12.8%).

5.12. Solubility in a water medium

Introduce 10 g of PVPP in a 200 ml flask containing 100 ml of distilled water. Mix and leave for 24 hours. Filter through a gauze screen with a porosity of 2.5 m and then through a gauze screen with a porosity of 0.8 m. The residue left from the evaporation of dried filtrate over 100°C hot water, must be less than 50 mg (solubility in water must be less than 0.5%).

5.13. Solubility in acid and alcohol.

Introduce 1 g of PVPP in a flask containing 500 ml of the following mixture

Acetic acid

3 g

Ethanol

10 ml

Water

100 ml

Let sit 24 hours. Filter through a gauze screen with a porosity of 2.5 m and then through a gauze screen with a porosity of 0.8 μm. Concentrate the filtrate over 100°C hot water. Stop evaporation over a 100° C hot water in a 70 mm diameter previously weighed silica capsule. The residue left by dry evaporation must be less than 10 mg, taking into account the residue left by evaporation of 500 ml of a mixture of acetic- acid ethanol (solubility in acetic acid and alcohol medium must be less than 1%).

  1. PVPP efficiency with regards to adsorption of polyphenolic compounds

6.1.    Salicylic acid essay

6.1.1.  Reagents:

  • M sodium hydroxide solution
  • 0.1M salicylic acid solution (13.81 g salicylic acid are dissolved in 500 ml of methanol and diluted with 1l of water).
    1.   Operating mode
  • Weigh 2-3 grams of PVPP in a 250 ml conical flask and write down the MASS M at 0.001 g.
  • Add the 0.1M salicylic acid solution according to the following formula:

  • Close the flask and shake for 5 minutes.
  • Pour the 25°C mixture on a filter over a Büchner funnel connected to a 250 ml tube; empty it until there is at least 50 ml of filtrate (the filtrate must be clear).
  • Use a pipette take 50 ml of the filtrate and put it in a 250 ml conical flask.
  • Determine the neutralisation point of phenolphthalein and write down the volume Vs with a 0.1M sodium hydroxide solution.
  • Titrate 50 ml of the salicycal acid solution (sample test) in the same manner and write down the volume Vb.
    1.   Calculation:

 

The percentage of activity must be equal or greater to 30%.

6.2.    Determining the adsorption capacity of oenocyanine (30% minimum)

6.2.1.  Principle

A small amount of PVPP is put in contact with a oenocyanine solution for 5 minutes. Adsorption at 280 nm of treated oenocyanine solution is compared to a standard solution and a blank solution made up of only solvent. The decrease of adsorption to 280 nm is used as a relative measurement of PVPP capacity to adsorb oenocyanine

6.2.2.  Reagents

  • oenocyanine (hydrate of)
  • Ethanol (absolute)
  • Distilled water.

6.2.3.  Material

  • Spectrophotometer, UV visible.
  • Quartz cuvettes, 1 cm of optical path.
  • Beakers, 150 ml.
  • Graduated flask, 1 litre.
  • Teflon stirring rods and magnetic mixer.
  • Syringes.
  • Filters for syringes, (0,45 μm porosity).

6.2.4.  Methods

  • Solution E. Dissolve 80 mg of oenocyanine hydrate in 50 ml of ethanol. Quantitatively transfer to a one litre graduated flask (with distilled water) and dilute to volume indicated with the distilled water. Label this solution E, and keep in an amber coloured tube. This is the standard solution.
  • Solution R. Prepare the reference solution by diluting 50 ml of ethanol in 1 litre of distilled water. This is the reference solution.
  • Weigh 3 volumes of, 50 mg 0,1 mg of samples in 150 ml beakers. Add the Teflon mixing rods and put under the magnetic mixer.

NOTE: The contact time between the sample and the solution is critical. In the following steps, the addition of the solution to the samples will be in increments in order to foresee exactly 5 minutes between the introduction of the solution and the filtration of each sample.

  • Using a pipette, add 100 ml of sample solution E, to 2 of the solutions and add 100 ml of solution R to the third sample. Put the timer on, once the 100 ml has been added.
  • Shake for 5 minutes 5 seconds.
  • With the aid of syringe and a filter with pores measuring 0.45 μm in diameter, withdraw a part of the solution immediately and filter in a clean flask. The filtered solutions can be stored in a cool and dark place for maximum 1 hour before measuring UV absorbency.
  • Set up the UV spectrophotometer in compliance with manufacturers’ instructions in order to measure absorbency at 280 nm. Put the machine at zero on 280 nm and use the R solution as a blank.
  • Measure the degree of absorbency of each filtered extract at 280 nm compared to solution R by using quartz cuvettes with 1 cm optical path.
    1.   Calculations

 

 

Given that:

  • Ao = Solution E absorbency
  • AT = Sample solution absorbency
  • AB = Blank solution absorbency (PVPP without oenocyanine)

Calculate the average for the two sample solutions.

  1. Determining of the N-vinyl-2-pyrrolidone monomer in PVPP with the aid of high performance liquid chromatography with UV detection.

7.1.    Principle

The N-vinyl-2-pyrrolidone monomer is the extract PVP polymer with methanol. The methanol solution is analysed by HPLC by using C8 type deactivated reversed phase column. This quantification is carried out by UV detection at 235 nm. Soluble PVP is eliminated when entering the column by a back flush technique.

This method can be applied to samples of which the monomer concentration is between 0.4 and 100 mg/l. The content of N-vinyl–2–pyrrolidone in PVPP should not exceed 10 mg per kg.

7.2.    Reagents

  • Methanol, HPLC grade.
  • water, micro filtered rest > 18 M.
  • N-vinyl-2-pyrrolidone

7.3.    Equipment

7.3.1.  Glassware

  • Assembling HPLC to filter solvents; entirely in glass.
  • Filters for mobile phases, nylon 0.45 μm.
  • Graduated pipettes (10, 20 and 100 ml).
  • Volumetric flasks (100 and 1000 ml).
  • 7.5 ml polyethylene pipettes
  • Spatulas used for the handling of powder grams.
  • Small flasks with polyethylene stoppers.
  • Filters with porosity 0.45 μm in glass microfibers.

7.3.2.  Instruments

  • Scale, which can measure to the nearest 0.1 mg.
  • Magnetic mixer
  • HPLC system with type C8 column and UV-Visible detector.

7.4.    Procedure

7.4.1.  Preparation of the mobile phase

  • Using a pipette, introduce 200 ml of HPLC grade methanol in a 1000 ml flask. Dilute as needed, with HPLC grade water and mix.
  • Filter/degasify the mobile phase and then transfer to the solvent reservoir to pump HPLC.

 

7.4.2.  Preparation of reference solution

  • VP 1000 mg/l reference solution
  • Weigh about 100 mg of N-vinyl-2-pyrrolidone to the nearest 0.1 mg in a 100 ml volumetric flask. Dilute the volume as needed with the mobile phase
  • VP 100 mg/l reference solution
  • Dilute 10 ml of the solution at 1000 mg/l to the needed volume, with the mobile phase, in a 100 ml volumetric flask.
  • VP 10 mg/l reference solution
  • Dilute 10 ml of the solution at 100 mg/l to the needed volume, with the mobile phase, in a 100 ml volumetric flask.
  • VP 1 mg/l reference solution
  • Dilute 10 ml of the solution at 10 mg/l to the needed volume, with the mobile phase, in a 100 ml volumetric flask.

7.4.3.  Preparation of the sample

  • In a small flask, weigh about 2.0 g of PVPP ±  0.1 mg.
  • Using a pipette, introduce 20 ml of HPLC grade methanol in the flask containing the sample.
  • Close the flask vacuum tight and put it under an automatic mixer. Extract for 1 hour at a speed of 130 rotations per minute.
  • After one hour, remove the flask from the mixer. Filter the supernatant with a filter with a porosity of 0.45 m in glass micro fibres.

7.4.4.  Analysis by HPLC

Install the HPLC equipment in compliance with the manufacturers’ instructions and balance the column and the detector with the mobile phase for at least one hour before analysing the reference test specimen and the samples.

HPLC conditions  (as an example)

Vol. injection

20 micro litres

Solvent flow

1 ml/minute

Detection

235 nm

Duration 10 minutes for reference solutions without back flushing (60 minutes for samples with back flushing of columns) of which 10 minutes for back flushing and 50 minutes for the reconditioning of the column.

Inject a reference specimen of 10 mg/l de N-vinyl-2-pyrrolidone (absolute concentration) three times every 6 to 10 samples to control the performance of the system.

7.5.    Calculations

Comment

  • Detection limit and minimum quantifiable quantity
  • Detection limit (signal/noise = 3 for PVPP sample with a content of 0.27 mg/l in N-vinyl-2-pyrrolidone) is ~ 0.10 mg/l with a minimum quantifiable (signal/noise = 10) of 0.33 mg/l.
  • Recovery
  • During a laboratory test, the N-vinyl-2-pyrrolidone, overloaded with PVPP with 1.10 and 100 mg/l of VP, was respectively recovered at 108%, 99.0% and 102%.
  • Retention time
  • The average length of peak retention of N-vinyl-2-pyrrolidone (at a rate of 10 mg/l) is 6.34 0.08 minutes, for a column system + 13 cm long precolumn.
  • Interferences
  • The appropriate duration for back flushing will be set for each system, otherwise a rigorous blocking of the column will take place.
  1. Determining the FREE N,N'- divinylIMIDazolidone in the PVPP BY gas chromatography.

This must be determined when the PVPP preparation technique N,N'-divinylimidazolidone.

the free N,N'-divinylimidazolidone in PVPP must not exceed 2 mg per kg.

8.1.    Principle

Measuring by gas chromatography on a capillary column of free N',N-divinylimidazolidone in a solvent (acetone) from non-soluble PVPP. Detection limit is 1 mg/kg.

8.2.    Internal test specimen solution:

Dissolve 100 mg 0.1 mg, of heptanoic acid in 500 ml of acetone.

8.3.    Preparation of the sample

Weigh 2 to 2.5 g 0.2 mg of polymer and pour into a 50 ml conical flask. Using a pipette, add 5 ml of internal standard solution, then 20 ml of acetone. Shake the mixture for 4 hours. Leave for 15 hours to stabilize and analyse the supernatant by gas chromagraphy.

8.4.    Calibration solution

Weigh 25 mg 0.2 mg of N,N'- divinylimidazolidone (The analytic al standard can be obtained from specialized laboratories, actually : BASF, D-67056 Ludwigshafen) and pour into a volumetric flask; add acetone up to 100 ml. Using a pipette, transfer 2.0 ml of this solution in a 50 ml volumetric flask and add acetone up to 50ml. Transfer 2 ml of this solution to a 25 ml volumetric flask, add 5 ml of internal standard solution (see above) and adjust the volume with acetone.

 

8.5.    Gas chromatography conditions (as an example):

Column (fused silica) capillary (cross linked carbowax - 20 M), length 30 m, innerdiameter 0.25 mm, film thickness 0.5 μm.

Programmed column temperature: 140°C to 240°C, 4°C/ minute.

Injector

  • split injector, 220°C.
  • Flow rate 30 ml/min.

Detector

  • Thermionic detector (optimised in compliance with
  • manufacturer’s’ instructions), 250°C.

Carrier gas: Helium, 1 bar (suppression).

Volume injected: 1 µl of sample floating to the up solution or reference test sample solution.

8.6.    Procedure

Validation of response factor for specific conditions of analysis is possible thanks to repeated injections of calibration solutions.

Analyse the sample. The N,N'- divinylimidazolidone content in non-soluble PVPP must not exceed 0.1%.

8.7.    Calculation of response factor:

  • Wd: quantity of N,N'-divinylimidazolidone used (mg)
  • Wse: quantity of internal standard used (mg)
  • Ase: peak area of standard solution
  • Ad:peak area of N,N'- divinylimidazolidone .

8.8.    Calculation of N,N'-divinylimidazolidone content:

  • Cd = concentration of N,N'-divinylimidazolidone (mg/kg)
  • f = response factor
  • Ad = peak area of N,N'-divinylimidazolidone
  • Wse = quantity of internal standard added to the sample (mg)
  • Ase = peak area of internal standard solution
  • Ws = quantity of sample used (g)
  1. Storing conditions

PVPP must be kept in a ventilated place in vacuum packed containers away from volatile elements that is might adsorb.

 

Annex Karl-Fischer procedure

 

  1. Field of application

This method is used to determine the water content in a transverse link PVP. Vinylpyrrolidone residue does not interfere with the usual rate present (0.1%). This method is able to detect water with concentrations above 0.05% (m/m).

  1. Principle

The sample is dissolved in anhydrous methanol and titrated using a Karl-Fischer reagent (KF) without pyridine. Water reacts to the titrating solution in the following way:

The final point (excess I2) is determined by controlling the change in current between two micro-electrodes and the polarized platinum. The typical KF titration is completely automated and directly produces the calculated water levels.

  1. Reagents

Karl Fischer reagent without pyridine (example by AQUASTAR AXI698A or the equivalent)

anhydrous methanol

Silica gel with humidity indicator for desiccation of the tube in the cell.

The analytic al standard can be obtained from specialized laboratories (actually: BASF, D-67056 Ludwigshafen)

  1. Apparatus

Karl Fischer Titrimeter

  1. Method

5.1.    Fill the titration recipient with 50 ml of anhydrous methanol or an amount sufficient tocover the electrodes. Fill the desiccation tubes above the cell of the fresh silica gel.

5.2.    Calibrate the titration solution by using distilled water as a specimen.

Record the weight of the sample and the tare, as indicated in the instrument instruction booklet.

The apparatus will automatically calculate the average titer and will store the figure for three testings. (the assay solution H20/ml in grams). If an analytical balance is available for reporting the sample weight, follow instructions in the manual.

5.3.    Add 0.075 g to 0.150 g of sample (to the nearest 0.1 mg) in a reaction recipient and mix for 2 minutes. Report the weight of the sample and the tare. The apparatus will measure the assay and automatically determine the % water content.

5.4.    Carry out analysis in duplicate

  1. Calculation

6.1.    Titrate the assay solution KF, T

6.2.    % of water in the sample

Where

  • V = ml of assay solution used
  • S = weight of samples in grams
  1. Interferences

High concentrations of vinylpyrrolidone (>0.5%) residues react with iodine and produce very imprecise results.

(A 1% vinylpyrrolidone residual rate corresponds to a H20 rate taken from 0.16% (m/m).

An excess base in the sample risks changing the solution pH and can produce low level results. Samples with pH levels >8 should be buffered with 5 g benzoïc acid for 50 ml.

Cation exchange resins

COEI-1-RESECA Cation exchange resins

  1. Objective, origin and scope of application

Ion exchange is the reversible exchange of ions between a liquid and a solid, during the course of which the solid does not undergo any substantial changes.  When this technique is applied to wine, the solid is an insoluble, permeable synthetic resin capable of exchanging ions with the wine with which it is in contact.

These resins are used in the tartaric stabilization of wine.

  1. Composition

Cation exchange resins may be prepared in an appropriate physical form using one or more of the following formulas.

Sulfonated styrene-divinylbenzene copolymer:

Divinylbenzene-methacrylic acid copolymer

Resin inertia must be satisfactory.

The substances which can be used in the manufacture of these resins are indicated in Annexes 1 and 2.

The resin should not contain more than 1 mg of extractable organic substance per kg. These organic extracts are obtained with each of the following solvents: a) distilled water, b) alcohol, 15% by volume, c) 3% acetic acid solution (m/m).

The resin must have been washed and conditioned in accordance with the manufacturer's instructions.

Prepare different ion exchange columns for each solvent, using 50 ml of the resin that has previously been weighed.

While maintaining the maximum temperature that may be encountered during use, pass the three solvents used in the analysis (distilled water, 15% hydroalcohol ic solution and 3% acetic acid solution (m/m)) through the resins at a flow rate of 350-450 ml per hour.

The first liter of effluent from each solvent should not be considered for analytical purposes; only the following two liters of each solvent should be used to analyze the organic extracts.

Total extract: The two liter sample should be evaporated at 105 °C until a constant weight is obtained.

Ash: This dry residue derived drom evaporation of the 2 liters of effluent is then burned in an oven at 850 °C until a constant weight is obtained.

Organic extract: Total extract minus total ash gives the organic extract. If the organic extract is greater than 1 ml/l of solvent used, a "blank" should be made using the solvent and a correction should be made by subtracting the organic extract found in the "blank" from that obtained during the resin test. The solvents used are prepared as follows:

 

Control reagents: Distilled and/or de-ionized water.

Ethyl alcohol at 15% by volume obtained from absolute ethyl alcohol and distilled and/or de-ionized water.

3% acetic acid produced by mixing 3 parts (by mass) of acetic acid with 97 parts (by mass) of distilled and/or de-ionized water.

  1. Limits
  • The treatment must not alter the nature of the wine.
  • The treatmnt must not reduce the color intensity of the wine.
  • The treatment must not decrease the concentration of metallic cations in the wine below 300 mg/l.
  • The treatment must not lower the wine's pH below 3.0.  The decrease in pH should not exceed 0.3 pH units.
  • The resin must not leave substances in the wine or impart to it characteristics (as a result of the resin-based treatment) that do not ordinarily exist in wine.
  • The winemaker may use conditioning agents and/or regenerants composed of water and inorganic acids, bases or salts, provided that the conditioned or regenerated resin is washed in water until all conditioning agents and regenerants are removed before adding the wine.

Annex 1:List of substances used in the manufacture of adsorbant ion-exchange resins used to condition foodstuffs.

List 1Substances assessed by an international organization

Name

PM/REF

Case

Restrictions

Monomers and other

Starting substances

 

n-butyl acrylate

10780

00141-32-2

-

Ethyl acrylate

11470

00096-33-3

-

Acrylonitrile

12100

00107-13-1

SML = ND

(DL = 0.02 mg/kg)

SML = 15 mg/kg

Formaldehyde

17260

00050-00-0

 

Methyl methacrylate

21130

00080-62-6

-

Methanol

21550

00067-56-1

-

Styrene

24610

00100-42-5

-

Chemical Modifiers

Carbonic acid, salts

42500

-

-

Hydrochloric acid

72640

07664-38-2

-

Silicic acid, salts

85980

-

-

Sulfuric acid

91920

07664-93-9

-

Acetic anhydride

10150

00108-24-7

-

tert-butyl-4-hydroxyanisole (BHA)

40720

25013-16-5

SML=30 mg/kg

Diethylene triamine

15790

00111-40-0

SML= 5 mg/kg

Dimethylamine

49225

00124-40-3

SML=0.06 mg/kg

2-(dimethylamino)ethanol

49235

00108-01-0

SML=18 mg/kg

Formaldehyde

54880

00050-00-0

SML=15 mg/kg

Hexamethylenediamine

18460

00124-09-4

SML=2.4 mg/kg

Potassium hydroxide

81600

01310-58-3

-

Sodium hydroxide

86720

01310-73-2

-

Sodium nitrite

86920

07632-00-0

SML=0.6 mg/kg

Ethylene oxide

17020

00075-21-8

MQ=1 mg/kg in FP

2-propanol

81882

00067-63-0

-

Polymerization Additives

Akylsulfonic acids (C8-C22)

34230

-

SML=6 mg/kg

Linear, primary alkylsulfuric

34281

-

-

acids (C8-C22)  having an even number of carbon atoms

Formic acid

55040

00064-18-6

-

Carboxymethylcellulose

42640

09000-11-7

-

Stannic chloride(IV)

93420

07646-78-8

-

Methylene chloride

66620

00075-09-2

SML=0.05 mg/kg

1,4-dihydroxybenzene

48620

00123-31-9

SML=0.6 mg/kg

Gelatin

55440

09000-70-8

-

Ammonium hydroxide

35600

01336-21-6

-

Magnesium hydroxide

64640

01309-42-8

-

Hydroxyethylcellulose

60560

09004-62-0

-

Hydroxethylmethylcellulose

60880

09032-42-4

-

Methanol

65960

00067-56-1

-

Methylcarboxymethylcellulose

66200

37206-01-2

-

Methyl isobutyl ketone

66725

00108-10-1

SML=5 mg/kg

Toluene

93540

00108-88-3

SML=1.2 mg/kg

Annex 2: Substances that may be used provisionally to manufacture ion-exchange resins.

List 2

Substances not fully evaluated by an international organization

Name

PM/Ref

Case

Restrictions

Monomers and other starting

substances

Ethylene glycol dimethacrylate

20440

00097-90-5

-

Divinylbenzene

16690

01321-74-0

-

Diallyl ether of 1,1,1-tri- methylolpropane

25645

00682-09-7

-

2,3-epoxypropyl methacrylate

20590

00106-91-2

-

2-methyl-1,3-butadiene

21640

00078-79-5

-

1,7-octadiene

22585

03710-30-3

-

1,1,1-trimethylolpropane trimethacrylate

25840

03290-92-4

-

Chemical Modifiers

N,N-dimethyl-1,3-diamino- propane

49380

00109-55-7

-

Triethylamine

95270

00121-44-8

-

Triethylene tetramine

25520

00112-24-3

-

Polymerization Additives

Polyvinyl alcohols

81280

09002-89-5

-

4-tert-butylcatechol

40640

00098-29-3

-

Diisobutyl ketone

49050

00108-83-8

-

Sodium hypochlorite

62110

07681-52-9

-

Isobutanol

62270

00078-83-1

-

4-methoxyphenol

66030

00150-76-5

-

Methylene bis(sodium naphtha- lenesulfonate)

66600

26545-58-4

-

2-methyl-2-pentanol

66860

00108-11-2

-

Dibenzoylperoxide

46440

00094-36-0

 

Partially hydrolyzed vinyl polyacetate

81260

-

-

Substances not evaluated by an international organization

Name

PM/Ref

Case

Restrictions

Monomers and other starting substances

Dimethoxymethane

-

00109-87-5

-

Diethylene glycol divinyl ether

-

00764-99-8

 

Ethyl vinyl benzene

-

28106-30-1

-

1,2,4-trivinyl cyclohexane

-

02855-27-8

-

Chemical Modifiers

Chlorosulfonic acid

-

07790-94-5

-

Monochloroacetic acid

-

00079-11-8

-

Phosphoric acid

-

13598-36-2

-

Bromine

-

07726-95-6

-

2-chloroethanol

-

00107-07-3

-

Methyl chloride

-

00074-87-3

-

1,2-dichloroethane

-

00107-07-3

-

1,2-dichloropropane

-

00078-87-5

-

3-(dimethylamino)propane

-

03179-63-3

-

Name

PM/Ref

Case

Prescriptions

Monomers and other starting substances

Methylic chloromethyl ether

-

00107-30-2

-

Nitrobenzene

-

00098-95-3

-

Potassium nitrite

-

07758-09-0

-

Phthalimide

-

0085-41-6

-

Sulfur trioxide

-

07446-11-9

-

Trimethylamine

-

00075-50-3

-

Polymerization additives

Lignosulfonic acid

63940

08062-15-5

-

Peracetic acid

-

00079-21-0

-

Polyacrylic acid

76460

09003-01-4

-

Poly(styrenesulfonic) acid

-

09080-79-9

-

Acrylamide/acrylic acid copolymer

-

09003-06-9

-

Ethoxylated, propoxylated tert-alkylamines (C12-C14)

-

68603-58-7

-

Maleic anhydride-styrene copolymer, ammonium salt

-

26022-09-3

-

Attapulgite

-

12174-11-7

-

Azobisisobutyronitrile

-

00078-67-1

-

1,1-bis(tert-butylperoxy)-3,3,5- trimethylcyclohexane

-

06731-36-8

-

n-Dodecyl mercaptan

-

25103-58-6

-

Poly(ethylene/propylene)glycol monobutyl ester

-

09038-95-3

-

Polyethylene glycol octylphenyl ether

78560

09002-93-1

 

Poly(ethylene-propylene/glycol ether with 1,1,1-tromethylol-propane

-

52624-57-4

-

tert-hexadecyl mercaptan

-

25360-09-2

-

Cumyl hydroperoxide

-

00080-15-9

-

Isododecane

62405

31807-55-3

-

Isooctane

-

26635-64-3

-

Mono- and dialkyl (C10-C18) Sulfonamides

-

-

-

Silver nitrate

-

07761-88-8

-

n-Octane

-

00111-65-9

-

tert-Butyl peracetate

-

00107-71-1

-

tert-Butyl perbenzoate

-

00614-45-9

-

bis(4-tert-butylcyclohexyte) percarbonate tert

-

15520-11-3

-

Butyl per(2-ethyl-hexanoate)

-

03006-82-6

-

tert-Butyl peroctanoate

-

13467-82-8

-

Dilauroyl peroxide

-

00105-74-8

-

Poly(diallyldimethylammonium chloride

-

26062-79-3

-

Polyvinylpyrrolidone

81500

09003-39-8

 

Sorbic acid

COEI-1-SORACI Sorbic acid

Trans,trans-hexa-2-4-dienoic acid

CH3-CH=CH-CH=CH-COOH

= 112.1

SIN NO. 200

  1. Objective, origin and scope of application

This product falls under the category of antifungal preservatives (see potassium sorbate). Because it is not soluble in wine, it cannot be used as is,  but rather in its potassium salt form. It may be soluble in some spirits.

Its use is subject to regulatory restrictions on content.

  1. Labelling

The label should indicate the product's purity and its safety and storage conditions.

  1. Solubility

Water at 20 °C

1.6 g/l

Water at 100 °C

38 g/l

Alcohol

55 g/l

Ethyl ether

104 g/kg

This acid can be entrained in steam.  At 100 °C, the steam has a sorbic acid concentration equal to 59% of the concentration of the dilute, boiling solution.

The ethyl ether/water partition coefficient is 32.

  1. Identifying Properties

4.1.  Melting point: 134 2 °C. Boiling point: 228 °C.

4.2.  Stir 20 mg of sorbic acid with 1 ml of brominated water (R).  The color should disappear.

4.3.  A solution containing 4 mg of sorbic acid per liter of water containing 0.5 g of monosodium carbonate per liter has an absorption band of 256 nm.

  1. Tests

5.1.  Moisture

Not more than 0.5% of sorbic acid must be made up of water (Karl Fisher method).

5.2.  Sulfuric Ash

The proportion of sulfuric ash is determined as indicated in the Annex. It should be less than 0.2 per 100.

5.3.  Preparing the Solution for Tests

Shake 0.5 g of sorbic acid with 70 ml of boiling water. Let the solution cool. Filter and collect the filtrate in a 100 ml volumetric flask. Wash the first container and the precipitate and the filter several times with several ml of water until 100 ml of filtrate is obtained.

5.4.  Sulfates

To 20 ml of solution prepared for tests under paragraph 5.3, add 1 ml hydrochloric acid diluted to 10 pp 100 (R) and 2 ml of barium chloride solution (R). The mixture should be clear, or the opalescence observed after 15 minutes should be less than that of the control solution prepared as indicated in the Annex. (Sulfate content expressed in terms of sulfuric acid should be less than 1 g/kg).

5.5.  Chlorides

To 10 ml of solution prepared for tests under paragraph 5.3, add 5 ml of water, 5 ml of nitric acid diluted to 10 pp 100 (R) and 0.5 ml of 5 pp 100 silver nitrate solution (R).  The mixture should be clear or the opalescence observed after 15 minutes should be less than that of the control solution prepared as indicated in the Annex. (Chloride content expressed in terms of hydrochloric acid should be less than 1 g/kg).

5.6.  Heavy Metals

Take 10 ml of the solution prepared under paragraph 5.3. Add 2 ml of pH 3.5 (R) buffer solution, and 1.2 ml of thioacetamide reagent (R).  Use the method described in the Annex. (Heavy metal content expressed in terms of lead should be less than 10 mg/kg).

5.7.  Lead

Using the technique described in the Compendium, determine lead content in the test solution (5.3). (Lead content to be less than 2 mg/kg.)

5.8.  Mercury

Using the technique described in the annex, determine mercury content in the test solution (5.3). (Content to be less than 1 mg/kg.)

5.9.  Arsenic

Using the technique described in the annex, determine arsenic content in the test solution (5.3). (Content to be less than 3 mg/kg.)

5.10.        Aldehydes

Prepare a saturate aqueous sorbic acid solution by agitating 1 g of sorbic acid with 35 ml of very hot water. Let cool in a corked flask. Filter and collect the filtrate in a 50 ml volumetric flask.  Wash the flask, the precipitate and the filter several times with several ml of water until 50 ml of filtrate are obtained. Treat the solution with 0.5 ml of fuchsin solution bleached out with sulfuric acid (R). After 15 minutes, compare it to a control tube produced with 0.5 ml of the same reagent and 1 ml of formaldehyde in solution with 20 μg per ml. The resulting coloration should be less intense than that of the control.  (Aldehyde content, expressed in terms of formaldehyde, should be less than 1 g/kg).

5.11.        Quantitative Analyses

These analyses must be performed using sorbic acid which has previously been dried in a desiccation chamber with sulfuric acid for 24 hours.

1° Weigh a quantity p of sorbic acid of about 0.20 g and dissolve it in 10 ml of pure alcohol. Then dilute in 100 ml of water.  Titrate the acidity using a 0.1M solution of sodium hydroxide in the presence of phenolphthalein solution (R). Let n be the amount in ml used: 1 ml of 0.1M sodium hydroxide solution corresponds to 0.0112 g of sorbic acid. Content in pp 100 of sorbic acid in the product tested:

2° The same procedure should be performed after entrainment in steam. Place 10 ml of the alcoholic solution containing a quantity of p grams of sorbic acid (about 0.2 g) in the bubble chamber of a steam distillation machine. Add a crystal (about 0.5 g) of tartaric acid and distill at least 250 ml (until the steam no longer distills acid). Titrate the distilled acidity using a 0.1M sodium hydroxide solution.

Using these two analyses, the product tested should contain at least 98 pp 100 sorbic acid.

  1. Storage

Sorbic acid should be stored in hermetically sealed, airtight containers.

Liquid sulfur dioxide

COEI-1-SOUDIO Liquid sulfur dioxide

Liquid sulfurous anhydride

Sulfuris dioxydum solutum

= 64.07

SIN NO. 220

  1. Objective, origin and scope of application

Sulfur dioxide is a colorless, non-flammable gas with a sharp, suffocating odor.  It is stored and transported in liquid form in hardened steel tanks.  These solutions are not stable and should not contain less than 50 g/l SO2.

At a temperature of 20 °C, it is liquid under a pressure of 3.36 kg per square centimeter, or 3.30 bars.

Under standard pressure, its boiling point is -10 °C.  Its density is ρ20 = 1.383.

This product falls under the category of antiseptic and antioxidant preservatives.Its content level in wine is subject to the regulatory limits in force concerning quantities.

  1. Labelling

The label should indicate product SO2 content at the time of sale and its safety and storage conditions.

  1. Solubility

Water at 0 °C

79.79 l of sulfur dioxide per liter of water at standard pressure

Water at 20 °C

39.37 l of sulfur dioxide per liter of water at standard pressure

Alcohol, 95% by vol. at 20 °C 

114.48 l of sulfur dioxide per liter of water Hydrocarbons, fatty substances and other organic compounds: soluble

  1. Identifying properties

4.1.    Sulfur dioxide blackens a filter paper which is impregnated with mercury (I) nitrate.

4.2.    Sulfur dioxide turns a filter paper impregnated with potassium iodine and starch solution blue.  Then, the blue color disappears because of reduction of the iodine initially released.

4.3.    Sulfur dioxide has a strong, characteristic odor.

  1. Tests

5.1.    Non-volatile Substances

In a 500 ml container that has already been calibrated, collect 200 ml of liquid sulfur dioxide.  Weigh the container immediately afterward. Let ρ be the mass in g sampled.  Let the sulfur dioxide spontaneously evaporate.  After reheating the container and removing any gaseous sulfur dioxide it still contains, weigh the container which holds the residue from evaporation. The mass of this residue should be less than 0.01 pp 100.

5.2.    Preparing the Solution for Tests

Add 2 ml of concentrated nitric acid (R) and 5 ml of water to the residue left by evaporating 200 ml of sulfur dioxide (5.1). Place in a 100 °C water bath for 5 minutes. The remaining volume should be topped off with water to 200 ml.

5.3.    Copper

Take a sample which corresponds to 1 g of liquid sulfur dioxide from the test solution prepared under paragraph 5.2. Top off to 10 ml with distilled water and add 0.5 ml of 10 pp 100 (v/v) hydrochloric acid solution, 15 pp 100 (m/v) citric acid (R), 1 ml of 5M ammonium hydroxide solution (R) and 0.5 ml of 1 pp 100 sodium diethyldithiocarbamate solution (concentration: 1 pp 100) in alcohol at 40% by volume (R). If a yellow coloration appears, it should be less intense than that obtained by adding 1 ml of copper solution in a concentration of  0.01 g per liter (R), 9 ml of water, 0.5 ml of 10 pp 100 (v/v) hydrochloric acid solution, 15 pp 100 (m/v) citric acid (R), 1 ml of 5M ammonium hydroxide solution (R) and 0.5 ml of 1 pp 100 sodium diethyldithiocarbamate solution (concentration : 1 pp 100) in alcohol at 40% by volume (R). (Copper content should be less than 10 mg/kg).

5.4.    Iron

Take a sample of the solution prepared for tests under paragraph 5.2 corresponding to 1 g of liquid sulfur dioxide.  Top off to 5 ml with water. Add 1 ml of concentrated hydrochloric acid (R), one drop of 1 pp 100 potassium permanganate (R) and 5 ml of 5 pp 100 potassium thiocyanate solution. If a red coloration appears, it should be less intense than that obtained by a control prepared with 5 ml of iron solution in a concentration of 0.010 g of iron per liter (R) and the same quantities of hydrochloric acid and thiocyanate. (Iron content should be less than 50 mg/kg).

Iron may also be quantitatively analyzed using the atomic absorption spetrophotometry method detailed in the Compendium.

5.5.    Lead

In the test solution prepared under paragraph 5.2, determine the lead content using the method described in the Compendium. (Lead content should be less than 5 mg/kg). It is also possible to dose iron using the atomic photometry method described in the Annex.

Lead may also be quantitatively analyzed using the atomic absorption spetrophotometry method detailed in the Compendium.

5.6.    Mercury

Using the technique described in the annex, determine mercury concentration in the test solution (5.2). (Content should be less than 1 mg/kg.)

5.7.    Selenium

In a test tube, take a volume of the solution prepared for tests under paragraph 5.2 corresponding to 1.5 g of sulfur dioxide and top off to 2 ml with water. Add 8 ml of hydrochloric acid diluted to 30 pp 100 (R) and 50 mg of powdered anhydrous potassium sulfite (R) which has been verified to be selenium free. After dissolving, place the test tube in a 100 °C water bath. Examine the color in the tube after 15 minutes.

If a pink coloration appears, it should not be more intense than that obtained in a control prepared by adding 0.15 ml selenium dioxide solution in a concentration of 100 mg  selenium per liter (R), 1.85 ml of water, 8 ml of 30 pp 100 hydrochloric acid (R) and 50 mg of powdered, selenium-free anhydrous potassium sulfite and, after dissolving, by placing the test tube in a 100 °C water bath for 15 minutes.  (Selenium content should be less than 10 mg/kg).

5.8.    Arsenic

Using the technique described in the annex, determine arsenic concentration in the test solution (5.2). Concentration should be less than 3 mg/kg.

  1. Storage

Sulfur dioxide should be stored and delivered in a liquid state in metal cylinders equipped with a needle valve tap or slide valve and whose strength is checked regularly.  Keep the containers in a cool place.

Styrene-divinylbenzene beads

COEI-1-STYDVB Adsorbent styrene divinylbenzene beads

CAS N°9003-69-4

  1. Object, origin and scope of application

 

The adsorbent beads enable the reduction or elimination of organoleptic deviations characterised as “earthy-musty” by a physical process of adsorption.

The adsorbent beads are placed in columns complying with food contact standards to enable the percolation of the must or wine in accordance with the files in the OIV International Code of Oenological Practices. They adsorb the unpleasant-smelling molecules whose dimensions are smaller than the size of their pores. The desired effect is achieved through the combination of the volume of the styrene-divinylbenzene copolymer beads determined by the size of the pores, and the speed the must or wine passes through the beads. Contrary to treatments of fruit juices with these same beads, the flow rates for this application are extremely rapid.

  1. Composition

Adsorbent styrene-divinylbenzene beads should be manufactured according to good manufacturing practices from the following substances: styrene or ethenylbenzene or vinylbenzene (CAS No. 100-42-5) and divinylbenzene or diethenylbenzene (CAS No. 1321-74-0), which are approved substances for use in materials and articles intended to come into contact with foodstuffs. See ‘1. References’.

They are produced by the polymerisation of divinylbenzene (DVB) in the presence of styrene (or vinylbenzene), which functions as a cross-linking agent; the initial concentration of styrene may vary from 0.5% to 40% maximum.

The cross-linked styrene-divinylbenzene copolymer is completely insoluble. In the majority of cases, it forms the structure of ion exchange resins or electrodialysis membranes before their grafting. The adsorbent beads have a particle size of between 600 μm and 750 μm, and represent a specific surface area greater than or equal to 700 m2/g, with pore diameters of between 1nm and 40 nm maximum. The inertia of the styrene-divinylbenzene copolymer beads should be satisfied.

Adsorbent beads should undergo pre-treatment or pre-conditioning with absolute ethanol (100% vol.) by the provider in order to eliminate residual monomers. They should be rinsed and conditioned before use, in accordance with the manufacturer’s instructions.

  1. Labelling

 

The main characteristics should be indicated on the label, including the batch number, the expiry date and the storage conditions.

 

  1. Characteristics

They come in the form of odourless, porous, white beads. They are prepared and conditioned in wet form in 30-40% water, with the potential addition of sodium chloride, in order to prevent any drying out.

  1. Limits and test methods

 

5.1.   General statements

Adsorbent styrene-divinylbenzene copolymer beads or non-grafted resins, used in the treatment of foodstuffs, should comply with the following requirements:

  • They should not transfer any of their components into foodstuffs in quantities that could put human health at risk, or lead to an unacceptable modification of the composition of foodstuffs or an alteration of their organoleptic characteristics.
  • The determination of the release of organic substances (determination of total organic carbon: TOC) and migration tests for specific components are carried out by the manufacturer using “food simulants” under “conventional migration test conditions”. These tests are compulsory in order to obtain any authorisation for the commercialisation of resins or adsorbent styrene-divinylbenzene copolymer beads, or any food contact material.
  • The application of adsorbent styrene-divinylbenzene copolymer beads in must or wine requires determining the migration of the specific components of the beads using 3 simulants. The determination of the migration of the specific components should be carried out using the following simulants: water, acetic acid at 3% (w/v) and ethanol at 20% vol. Additional concentrations may be tested for applications in specific products (e.g. liqueur wines).
  • The contact time for the migration tests is 4 h, which is greatly superior to the contact time for the must or wine under treatment conditions, with this not exceeding several minutes.

 

5.2.   Determination of Total Organic Carbon (TOC)

5.2.1. Control reagents

  • Distilled and/or deionised test water with conductivity of less than 20 μS/cm at 25 °C and a TOC content of less than 0.2 mg/L.
    1. Protocol
  • Prepare 1 column and recover 100 mL test water from this column for a blank test (CB); the TOC content should be less than 0.5 mg/L,
  • prepare 100 mL adsorbent beads, whose weight will have previously been determined,
  • meanwhile, maintain the maximum temperature that can be reached during use (e.g. 20 °C),
  • introduce 100 mL test water into the column, and progressively add the 100 mL of adsorbent beads that should be immersed; after sedimentation, use lateral tapping to create vibrations in the column and thus pack the resin in tightly to a constant volume,
  • percolate 2 L test water through the resin, at a flow rate of 1000 mL per hour,
  • maintain stagnation of the water for 24 hours,
  • collect 5 successive fractions of 100 mL test water having undergone percolation through 100 mL adsorbent beads at a flow rate of 500 mL/h,
  • analyse the TOC of the 5 fractions collected and of the blank test (CB) using an automatic TOC analyser.

5.2.3. Results

The sum of the results of the analyses of the TOC from each collection deducted from the value of the TOC from the blank test should not exceed 10 mg/L (acceptability criteria).

5.3.   Migration testing of specific components: styrene and divinylbenzene

5.3.1. Objective

 

To verify that the profile of organic impurities or specific components of the adsorbent beads after pre-treatment by the manufacturer is compliant:

  • a/ by estimating the total quantity of volatile organic impurities (styrene and divinylbenzene) present on the adsorbent beads,
  • b/ by estimating the proportion of these impurities that may migrate into a solution with an extraction power (solvents or simulants) comparable to that of must and wine.
    1. Solvents or simulants required

The following solvents are required:

  • test water: distilled and/or deionised water with conductivity of less than 20 μS/cm at 25 °C and a TOC content of less than 0.2 mg/L,
  • ethanol at 20% vol. obtained from absolute ethanol and distilled and/or deionised water,
  • acetic acid at 3% made up of a mixture of acetic acid and distilled and/or deionised water at the ratio of 3:97 (w/w).

5.3.3. Protocol

  • Prepare 1 column per simulant and sample 100 mL test water from this column for a blank test,
  • prepare 100 mL adsorbent beads, whose weight will have previously been determined,
  • meanwhile, maintain the maximum temperature that can be reached during use (e.g. 20°C),
  • introduce 100 mL test water into each column, and progressively add the adsorbent beads that should be immersed up to a volume of 100 mL; after sedimentation, use lateral tapping to pack the resin in tightly to a constant volume,
  • percolate 2 L of test water and of each solvent or simulant through the resins, at a flow rate of 1000 mL per hour,
  • maintain stagnation for 4 hours,
  • collect 5 successive fractions of 100 mL simulant having undergone percolation through 100 mL adsorbent beads at a flow rate of 500 mL/h,
  • analyse the specific components of the 5 fractions collected from each simulant and from the test water, and of the blank test, according to the method described in Annex 1.

 

5.3.4. Results

The specific migration limits (SML) are those of the analytical limit of detection, i.e. for divinylbenzene, the SML = not detected (ND), considering that the LOD = 0.02 mg/kg.

  1. Usage limits
  • The treatment should not change the organoleptic characteristics of the wine.
  • The treatment should not visibly modify the colour of the wine.
  • The treatment should not significantly reduce the concentration of metallic cations in the wine.
  • The treatment should not significantly modify the pH of the must or wine.
  • The resin should not release substances into the wine or must that could alter it.
  • The reduction of the alcoholic strength of the wine should not exceed 0.1%.
  • The operator may use conditioning and/or regenerating agents composed of water and inorganic acids, bases or salts, on the condition that the conditioned or regenerated resin is rinsed in water until the conditioning and regenerating agents are completely eliminated, before the introduction of the must or wine.
  1. Determination of the volume of adsorbent beads (bed volume, BV, and of the flow rate of the must or wine to be treated (BV/H)

It is recommended that laboratory tests are performed to determine the quantities of beads and the flow rate to be applied and transposed to large-volume treatment.

 

7.1.   Equipment

  • Chromatography column, 10 mm in diameter and 250 mm in length, with 2 PTFE frits with a pore diameter of 50 μm at the ends,
  • peristaltic pump,
  • 5 L or 10 L must or wine contaminated with geosmin per test,
  • adsorbent styrene-divinylbenzene copolymer beads.

 

7.2.   Method

To determine the optimal flow rate for the elimination of geosmin (BV/h), apply the test on a volume of 5 or 10 mL beads (BV), which corresponds reciprocally to a 5- or 10-L volume of wine or must to be treated, so that the ratio of resin to the volume of wine or must to be treated is 1:1000. The optimal flow rate falls within the range of 150-250 BV/h.

The must to be treated should undergo prior degradation of its pectins and filtration, so that its turbidity is less than 10 NTU and the pores of the beads are thus not obstructed.

  • Rinse the adsorbent beads well in water (osmosis water), then place in the column and tightly pack together by tapping on the column.
  • Introduce the wine or must into the column using the peristaltic pump at a pre-determined flow rate. Check the output flow rate of the wine every 30 minutes using a graduated burette, to ensure there is no clogging of the resin. After treatment, check the free SO2 and total SO2, in order to readjust their content in the wine if needed.
  • To verify that the treatment has no negative impact on the must or wine, carry out analyses on the 5 or 10 litres treated (Table 1).

Table 1: Analyses to be carried out before and after treatment

 

-

Reds

Whites

Alcoholic strength

X in the wine

X in the wine

Residual sugars

X in the wine

X in the wine

Total sugars

X in the must

X in the must

Volatile acidity

X

X

Total acidity

X

X

pH

X

X

Free and total SO2

X

X

OD 280 nm

X

X

OD 320 nm

X

X

OD 420 nm or CIELAB

X

X

OD 520 nm or CIELAB

X

 

OD 620 nm or CIELAB

X

 

The quantity of adsorbent beads and the flow rate will be readjusted, either according to the rate of elimination of geosmin demonstrated by analysis (SPME-GC-MS method, which is the internal method of COFRAC-accredited laboratories), or, if the treatment is urgent, by a simple tasting confirmed later by analysis.

  1. Regeneration

The adsorbent beads may be regenerated a maximum of 5 times, after the total or partial volume of must or wine has passed through.

Regeneration is carried out in the column by passing through a 4M sodium hydroxide solution with the slowest possible flow rate depending on the type of pump (e.g. 20 BV/h).

Rinsing is performed with drinking water of a known pH (initial pH), until the sodium hydroxide has been eliminated; this is controlled through measurement of the pH of the water used for rinsing, which should be identical to the initial pH.

 

  1. Conditions of use

Storage, use and regeneration of the adsorbent beads, and their disposal as waste, should be carried out according to the techniques permitted for food contact materials. The manufacturer is required to provide all necessary information for their use and regeneration. According to the legislation in force, the adsorbent beads are to be disposed of in approved industrial waste treatment centres for recycling, specifically through depolymerisation.

  1. References

 

  • Regulation (EC) No. 1935/2004
  • Regulation (EU) No. 10/2011, amended, Annex 1, Table 1
  • FDA regulations as found in Title 21 of the Code of Federal Regulations (CFR), Part 173 – Secondary Direct Food Additives permitted in food for human consumption, §173.65

 

Annex 1: Determination of styrene and divinylbenzene in wines (Type IV Method)

  1. Important notice

The user of this publication should be well aware of current laboratory practices. This publication is not intended to address any safety problems that may be related to its use. The user is responsible for establishing the appropriate health and safety practices, and ensuring respect for both the national regulations in force and the environment.

  1. Scope of application

TESTING OF MIGRATION OF SPECIFIC COMPONENTS

  1. Objective

 

To verify that the profile of organic impurities or specific components of the adsorbent beads after pre-treatment by the manufacturer is compliant.

a/ By estimating the total quantity of volatile organic impurities present on the adsorbent beads;

b/ by estimating the proportion of these impurities that may migrate into a solution with an extraction power (solvents or simulants) comparable to that of must and wine.

:1200px-Styrene_acsv.png 

:Unknown.png 

Styrene

Divinylbenzene

Divinylbenzene exists in 3 forms: ortho, meta and para.

  1. Standard references

ISO 78-2: Chemistry – Layouts for standards

  1. Principle of the method

The method is gas chromatography coupled to mass spectrometry. The sample is extracted in the headspace using the solid-phase microextraction (SPME) technique. The wine/must sample is prepared by adding, to an SPME vial, roughly 2 g NaCl with 10 mL wine/must and 50 μL ethyl

heptanoate solution (internal standard) solution at 20 mg/L. The vial is sealed and stirred for 5 minutes. The internal standard used here is given by way of example; it is possible to use other internal standards.

For the measurement, six calibration points are used based on a stock solution containing all of the molecules to be studied.

  1. Reagents and working solutions

During analysis – unless otherwise indicated – use only quality, recognised analytical reagents and distilled or demineralised water, or water of equivalent purity.

  1. Reagents
  • Type I or Type II water for analytical usage (ISO 3696 standard)
  • Ethanol (CAS No. 64-17-5)
  • Sodium chloride (CAS No. 7647-14-5)
  • Ethyl heptanoate (CAS No. 106-30-9)
  • Divinylbenzene (CAS No. 1321-74-0)
  • Styrene (CAS No. 100-42-5)

 

  1. Working solutions

Individual stock solutions at 1 g/L are prepared in ethanol for each molecule as well as for the internal standard (ethyl heptanoate).

Based on the individual stock solutions, working solutions are prepared with ethanol to the desired concentrations so as to cover the whole measurement range.

  1. Calibration solutions

In order to ensure traceability to the International System of Units (SI), the calibration range should be made up of solutions with 12% (v/v) ethanol (5.1.2) covering 6 points of the range of measurement (1-100 µg·L-1). These solutions are prepared at the time of analysis for single use.

The calibration equation obtained is a second-degree equation.

  1. Apparatus

 

The apparatus is given by way of example. The GC-MS technique used allows for the necessary variations or optimisations to be made according to the equipment configuration.

  • GC-MS equipped with a “split-splitless” injector and mass-spectrometer detector
  • Capillary column with apolar stationary phase, 5% phenylmethylpolysiloxane (e.g. HP-5MS, 30 m x 0.25 mm x 0.25 μm film) or equivalent
  • Calibrated 100- μL, 1- μL and 10- μL microsyringes
  • 20-mL SPME vial, sealable by a perforated capsule and Teflon®-faced cap
  • Solid-phase microextraction system (SPME) with polydimethylsiloxane-film-coated fibre of 100 μm in thickness
  • Balance
  • This should have 0.1 mg precision.
  • Measuring glassware

The measuring glassware for the preparation of reagents and calibration solutions is class A.

  1. Preparation of samples
    1.          Test samples

Place 10 mL wine/must in a 20-mL SPME glass vial (6.4) with roughly 2 g NaCl (5.1.3) and 50 µL ethyl heptanoate (internal standard) at 20 mg/L (5.1.4).

Seal the vial with a perforated cap and Teflon® seal (6.4).

11.2.         GC-MS Procedure

11.2.1.   Extraction

Carry out headspace SPME extraction for 25 minutes at room temperature.

11.2.2.   Injection

Carry out desorption from the fibre for 10 minutes in the injector.

Injector at 260 °C in splitless mode

Helium flow rate: 2mL/min

11.2.3.   Gas chromatography parameters

  • Column: 5MS UI 30 m x 0.25 mm x 0.25 μm
  • Transfer line: 300°C
  • Oven: 45°C
  • Then 2°C/min up to 80°C
  • Then 3°C/min up to 92°C
  • Then 40°C/min up to 300°C
  • Then 300°C for 2 minutes
  • Run time: 28.7 minutes
    1.    Acquisition
  • Source temperature: 230°C
  • Quad temperature: 150°C
  • Acquisition: SIM
 

Run time (min)

Ions (quantified)

Ions (qualified)

Ethyl heptanoate

15.0

88

113 / 101 / 158

Styrene

5.0

104

78 / 103 / 50

m,p-Divinylbenzene

15.4 & 16.1

130

128 / 115

  1. Results

Example chromatogram and calibration curve for styrene

 

Serveur_Labo:Labo:Vincent:styrene-cal.PNG

Example chromatogram and calibration curve for divinylbenzene

 

  1. Expression of results

The results are expressed in μg/L.

Grape sugar

COEI-1-SUCRAI Grape sugar (rectified concentrated grape musts)

  1. Objective, origin and scope of application

Grape sugar is obtained exclusively from grape musts.  The addition of grape sugar to wine is subject to regulation.

The label, or, when this is absent, the documentation accompanying the containers of grape sugar, must cite the sugar percentage.

  1. Properties

Syrupy, milk-white or slightly yellowish liquid with a sugary flavor.

Refraction index at 20 °C

1.42410-1.46663

Total sugar in terms of invert sugar

63% (m/m) minimum

Absorbance at 425 nm under 1 cm at 25° Brix

maximum 0.100

pH at 25° Brix

maximum 5 *

Titration acidity in mEq/kg of sugar

maximum 15 *

Sucrose by recommended method

negative

Sulfur dioxide in mg/kg of sugar

maximum 25

Folin-Ciocalteu index at 25° Brix

maximum 6

Total cations in mEq/kg of sugar

maximum 8

Conductivity at 25° Brix in Micro-Siemens/cm (μScm-1)

maximum 120

5-(hydroxymethyl)furfural in mg/kg sugar

maximum 25

Residual ethanol in g/kg sugar

maximum 8

Heavy metals in mg/kg grape sugar expressed in terms of lead

less than 10

No antiseptics and anti-fermenting agents

1° Brix = 1 g of sugar in 100 g of solution

* after vacuum removal of the carbon dioxide

  1. Tests

 

3.1.         Preparing the Sample

Drawing samples for the various different analyses is difficult; therefore. the following two dilutions are recommended:

3.1.1.  Principal Solution I - for the following tests: titration acidity, total sulfur dioxide and total cations

Weigh exactly 200 g of grape sugar.  Fill to 500 ml with water.

3.1.2.  Principal Solution II - necessary for the following tests: Folin-Ciocalteu index, pH, conductivity, sucrose test and absorbance at 425 nm.

Dilute the grape sugar with water until it has a concentration of 25° ± 0.5° Brix (25 g of sugar in 100 g of solution).

3.2.         Refraction Index at 20 °C (total sugars)

3.2.1.  Equipment:

The refractometer used gives the following, based on type of graduation:

  • 0.1% by mass of sucrose (or dry matter or Brix degrees)
  • the 5th decimal of the index of refraction

The refractometer used should be equipped with a thermometer (+ 10 °C at + 30 °C).

3.2.2.  Procedure Method:

Place two drops of grape sugar on the surface of the fixed prism.  Lower the moving prism and point the instrument toward a light source that illuminates the graduated scale. Observe the line of separation on this scale between a lower clear zone and an upper dark. Read the graduation line at which this line of separation occurs and record the temperature in °C.

3.2.3.  Calculation:

If the device is graduated in percentage (m/m) of sucrose (or dry matter or Brix degrees), the measurement converted to 20 °C using Table 2 is recorded in Table 1 which provides (Column 3) total sugar content in percent (m/m) expressed in terms of sugar.

If the device is graduated by refraction index, the index measured at t °C is used to obtain the corresponding value in percent of sucrose (m/m) at t °C in Table 1 (Column 1).  This value as expressed at 20 °C using the temperature correction table N° 2, transferred to Table 1, which, in Column 3, gives the total sugar number in percent (m/m) of invert sugar.

To obtain the refraction index at 20 °C, refer to the total sugar content expressed in terms of invert sugar in Table 1.

3.2.4.  Recording the Findings:

Total sugar content is expressed parts per 100 by mass of sucrose and is recorded with a decimal.

The refraction index at 20 °C is expressed to 5 decimal places.

3.3.         Absorbance of a 25° Brix Solution at 425 nm (Chromatic characteristics)[1]

Proceed to the analysis according to the method described in the Compendium of international methods of wine and must analysis (Method OIV-MA-F1-08).

3.4.         Measuring pH[2]

Proceed to the analysis according to the method described in the Compendium of international methods of wine and must analysis (Method OIV-MA-F1-06).

3.5.         Titration Acidity[3]

Place 10 ml of Principal Solution I in a cylindrical vessel (3.1.1).  Add Proceed to the analysis according to the method described in the Compendium of international methods of wine and must analysis (Method OIV-MA-F1-05).

3.6.         Sucrose Test by HPLC[4]

Proceed to the analysis according to the method described in the Compendium of international methods of wine and must analysis (Method OIV-MA-F1-04).

3.7.         Sulfur Dioxide[5]

Proceed to the analysis according to the method described in the Compendium of international methods of wine and must analysis (Method OIV-MA-F1-07).

3.8.         Folin-Ciocalteu Index of the 25° Brix Solution

Place the following, in order, in a 100 ml volumetric flask:

  • 5 ml of Principal Solution II
  • 50 ml water
  • 5 ml Folin-Ciocalteu reagent (R)
  • 20 ml of sodium carbonate solution (R)

Fill to the 100 ml level with water.  Stir to homogenize.  Wait 30 minutes for the reaction to stabilize.

Determine absorbance at 750 nm in 1 cm as compared with a control prepared with water instead of Principal Solution II.

Expressing the results:

Express the results in the form of an index obtained by multiplying the absorbance by 16 in order to obtain a scale comparable to that used for wines.

3.9.         Total Cations

Proceed to the analysis according to the method described in the Compendium of international methods of wine and must analysis (Method OIV-MA-F1-09).

3.10.     Conductivity of the Solution at 25° Brix[6]

Proceed to the analysis according to the method described in the Compendium of international methods of wine and must analysis (Method OIV-MA-F1-01).

3.11.     5-(Hydroxymethyl)furfural(HMF)[7]

Proceed to the analysis according to the method described in the Compendium of international methods of wine and must analysis (Method OIV-MA-F1-02)

3.12.     Heavy Metals

Proceed to the analysis according to the method described in the Compendium of international methods of wine and must analysis (Method OIV-MA-F1-10; Method OIV-MA-F1-11).

 (Heavy metal content, expressed in terms of lead, should be less than 10 mg/kg).

3.13.     Lead

Using the method set forth in the Compendium, quantitatively analyze lead in the Principal Solution I (3.1.1). (Lead content should be less than 1 mg/kg.)

3.14.     Mercury

Using the method set forth in the annex, quantitatively analyze mercury in the Principal Solution I (3.1.1). (Mercury content should be less than 0.3 mg/kg.)

3.15.     Arsenic

Using the method described in the annex, quantitatively analyze arsenic in the Principal Solution I (3.1.1). (Arsenic concentration should be less than 0.5 mg/kg.)

3.16.     Ethanol[8]

Proceed to the analysis according to the method described in the Compendium of international methods of wine and must analysis (Method OIV-MA-F1-03).

3.17.     Meso-Inositol

Gas phase chromatography of a silyl-containing derivative.

N.B. : The information given above is provided for informational purposes. There are other techniques for deriving sugars and polyhydroxy alcohols, and chromatographic methods for determining meso-inositol concentrations

3.17.1.                      Preparing the sample:

Dilute 5 g of grape sugar in 50 ml of water. Dry 50 μl of the dilution and 50 µl of a methyl D-glucopyranoside solution in a concentration of 1 g/liter, (internal standard) under a vacuum in a small 2 ml flask.

Dissolve the residue with 100 μl of pyridine. Add 100 μl of trimethylchlorosilane. Seal the small flask with a teflon stopper and heat at 80 °C for 1 hour. Inject 1 μl with division of the injected volume to 1/60.

3.17.2.                      Separation

Column: apolar capillary type of fused silica 25 m long and inner diameter of 0.2 mm.

Supporting Gas: helium, 1 ml/minute

Injector and detector: 280 °C

Column temperature: 60-250 °C, at 4 °C per minute, then isothermal at 250 °C.

3.17.3.                      Expressing the results: g per kg of sugar

  1. Storage

Grape sugar must be stored in impermeable containers and at ambient termperature from the time it is made.

Annex 1 (sugars)

Table 1 : Sugar content in musts using refractometry

Sucrose % (m/m)

Index of refraction at 20°C

Density at 20°C

Sugars in g/l

Sugars in g/kg

50.0

1.42008

1.2342

627.6

508.5

50.1

1.42029

1.2348

629.3

509.6

50.2

1.42050

1.2355

630.9

510.6

50.3

1.42071

1.2362

632.4

511.6

50.4

1.42092

1.2367

634.1

512.7

50.5

1.42113

1.2374

635.7

513.7

50.6

1.42135

1.2381

637.3

514.7

50.7

1.42156

1.2386

638.7

515.7

50.8

1.42177

1.2391

640.4

516.8

50.9

1.42198

1.2396

641.9

517.8

51.0

1.42219

1.2401

643.4

518.8

51.1

1.42240

1.2406

645.0

519.9

51.2

1.42261

1.2411

646.5

520.9

51.3

1.42282

1.2416

648.1

522.0

51.4

1.42304

1.2421

649.6

523.0

51.5

1.42325

1.2427

651.2

524.0

51.6

1.42347

1.2434

652.9

525.1

51.7

1.42368

1.2441

654.5

526.1

51.8

1.42389

1.2447

656.1

527.1

51.9

1.42410

1.2454

657.8

528.2

52.0

1.42432

1.2461

659.4

529.2

52.1

1.42453

1.2466

661.0

530.2

52.2

1.42475

1.2470

662.5

531.3

52.3

1.42496

1.2475

664.1

532.3

52.4

1.42517

1.2480

665.6

533.3

52.5

1.42538

1.2486

667.2

534.4

52.6

1.42560

1.2493

668.9

535.4

52.7

1.42581

1.2500

670.5

536.4

52.8

1.42603

1.2506

672.2

537.5

52.9

1.42624

1.2513

673.8

538.5

53.0

1.42645

1.2520

675.5

539.5

53.1

1.42667

1.2525

677.1

540.6

53.2

1.42689

1.2530

678.5

541.5

53.3

1.42711

1.2535

680.2

542.6

53.4

1.42733

1.2540

681.8

543.7

53.5

1.42754

1.2546

683.4

544.7

53.6

1.42776

1.2553

685.1

545.8

53.7

1.42797

1.2560

686.7

546.7

53.8

1.42819

1.2566

688.4

547.8

53.9

1.42840

1.2573

690.1

548.9

54.0

1.42861

1.2580

691.7

549.8

54.1

1.42884

1.2585

693.3

550.9

54.2

1.42906

1.2590

694.9

551.9

54.3

1.42927

1.2595

696.5

553.0

54.4

1.42949

1.2600

698.1

554.0

54.5

1.42971

1.2606

699.7

555.1

54.6

1.42993

1.2613

701.4

556.1

54.7

1.43014

1.2620

703.1

557.1

54.8

1.43036

1.2625

704.7

558.2

54.9

1.43058

1.2630

706.2

559.1

55.0

1.43079

1.2635

707.8

560.2

55.1

1.43102

1.2639

709.4

561.3

55.2

1.43124

1.2645

711.0

562.3

55.3

1.43146

1.2652

712.7

563.3

55.4

1.43168

1.2659

714.4

564.3

55.5

1.43189

1.2665

716.1

565.4

55.6

1.43211

1.2672

717.8

566.4

55.7

1.43233

1.2679

719.5

567.5

55.8

1.43255

1.2685

721.1

568.5

55.9

1.43277

1.2692

722.8

569.5

56.0

1.43298

1.2699

724.5

570.5

56.1

1.43321

1.2703

726.1

571.6

56.2

1.43343

1.2708

727.7

572.6

56.3

1.43365

1.2713

729.3

573.7

56.4

1.43387

1.2718

730.9

574.7

56.5

1.43409

1.2724

732.6

575.8

56.6

1.43431

1.2731

734.3

576.8

56.7

1.43454

1.2738

736.0

577.8

56.8

1.43476

1.2744

737.6

578.8

56.9

1.43498

1.2751

739.4

579.9

57.0

1.43519

1.2758

741.1

580.9

57.1

1.43542

1.2763

742.8

582.0

57.2

1.43564

1.2768

744.4

583.0

57.3

1.43586

1.2773

745.9

584.0

57.4

1.43609

1.2778

747.6

585.1

57.5

1.43631

1.2784

749.3

586.1

57.6

1.43653

1.2791

751.0

587.1

57.7

1.43675

1.2798

752.7

588.1

57.8

1.43698

1.2804

754.4

589.2

57.9

1.43720

1.2810

756.1

590.2

58.0

1.43741

1.2818

757.8

591.2

58.1

1.43764

1.2822

759.5

592.3

58.2

1.43784

1.2827

761.1

593.4

58.3

1.43809

1.2832

762.6

594.3

58.4

1.43832

1.2837

764.3

595.4

58.5

1.43854

1.2843

766.0

596.4

58.6

1.43877

1.2850

767.8

597.5

58.7

1.43899

1.2857

769.5

598.5

58.8

1.43922

1.2863

771.1

599.5

58.9

1.43944

1.2869

772.9

600.6

59.0

1.43966

1.2876

774.6

601.6

59.1

1.43988

1.2882

776.3

602.6

59.2

1.44011

1.2889

778.1

603.7

59.3

1.44034

1.2896

779.8

604.7

59.4

1.44057

1.2902

781.6

605.8

59.5

1.44079

1.2909

783.3

606.8

59.6

1.44102

1.2916

785.2

607.9

59.7

1.44124

1.2921

786.8

608.9

59.8

1.44147

1.2926

788.4

609.9

59.9

1.44169

1.2931

790.0

610.9

60.0

1.44192

1.2936

791.7

612.0

60.1

1.44215

1.2942

793.3

613.0

60.2

1.44238

1.2949

795.2

614.1

60.3

1.44260

1.2956

796.9

615.1

60.4

1.44283

1.2962

798.6

616.1

60.5

1.44305

1.2969

800.5

617.2

60.6

1.44328

1.2976

802.2

618.2

60.7

1.44351

1.2981

803.9

619.3

60.8

1.44374

1.2986

805.5

620.3

60.9

1.44397

1.2991

807.1

621.3

61.0

1.44419

1.2996

808.7

622.3

61.1

1.44442

1.3002

810.5

623.4

61.2

1.44465

1.3009

812.3

624.4

61.3

1.44488

1.3016

814.2

625.5

61.4

1.44511

1.3022

815.8

626.5

61.5

1.44534

1.3029

817.7

627.6

61.6

1.44557

1.3036

819.4

628.6

61.7

1.44580

1.3042

821.3

629.7

61.8

1.44603

1.3049

823.0

630.7

61.9

1.44626

1.3056

824.8

631.7

62.0

1.44648

1.3062

826.6

632.8

62.1

1.44672

1.3068

828.3

633.8

62.2

1.44695

1.3075

830.0

634.8

62.3

1.44718

1.3080

831.8

635.9

62.4

1.44741

1.3085

833.4

636.9

62.5

1.44764

1.3090

835.1

638.0

62.6

1.44787

1.3095

836.8

639.0

62.7

1.44810

1.3101

838.5

640.0

62.8

1.44833

1.3108

840.2

641.0

62.9

1.44856

1.3115

842.1

642.1

63.0

1.44879

1.3121

843.8

643.1

63.1

1.44902

1.3128

845.7

644.2

63.2

1.44926

1.3135

847.5

645.2

63.3

1.44949

1.3141

849.3

646.3

63.4

1.44972

1.3148

851.1

647.3

63.5

1.44955

1.3155

853.0

648.4

63.6

1.45019

1.3161

854.7

649.4

63.7

1.45042

1.3168

856.5

650.4

63.8

1.45065

1.3175

858.4

651.5

63.9

1.45088

1.3180

860.0

652.5

64.0

1.45112

1.3185

861.6

653.5

64.1

1.45135

1.3190

863.4

654.6

64.2

1.45158

1.3195

865.1

655.6

64.3

1.45181

1.3201

866.9

656.7

64.4

1.45205

1.3208

868.7

657.7

64.5

1.45228

1.3215

870.6

658.8

64.6

1.45252

1.3221

872.3

659.8

64.7

1.45275

1.3228

874.1

660.8

64.8

1.45299

1.3235

876.0

661.9

64.9

1.45322

1.3241

877.8

662.9

65.0

1.45347

1.3248

879.7

664.0

65.1

1.45369

1.3255

881.5

665.0

65.2

1.45393

1.3261

883.2

666.0

65.3

1.45416

1.3268

885.0

667.0

65.4

1.45440

1.3275

886.9

668.1

65.5

1.45463

1.3281

888.8

669.2

65.6

1.45487

1.3288

890.6

670.2

65.7

1.45510

1.3295

892.4

671.2

65.8

1.45534

1.3301

894.2

672.3

65.9

1.45557

1.3308

896.0

673.3

66.0

1.45583

1.3315

898.0

674.4

66.1

1.45605

1.3320

899.6

675.4

66.2

1.45629

1.3325

901.3

676.4

66.3

1.45652

1.3330

903.1

677.5

66.4

1.45676

1.3335

904.8

678.5

66.5

1.45700

1.3341

906.7

679.6

66.6

1.45724

1.3348

908.5

680.6

66.7

1.45747

1.3355

910.4

681.7

66.8

1.45771

1.3361

912.2

682.7

66.9

1.45795

1.3367

913.9

683.7

67.0

1.45820

1.3374

915.9

684.8

67.1

1.45843

1.3380

917.6

685.8

67.2

1.45867

1.3387

919.6

686.9

67.3

1.45890

1.3395

921.4

687.9

67.4

1.45914

1.3400

923.1

688.9

67.5

1.45938

1.3407

925.1

690.0

67.6

1.45962

1.3415

927.0

691.0

67.7

1.45986

1.3420

928.8

692.1

67.8

1.46010

1.3427

930.6

693.1

67.9

1.46034

1.3434

932.6

694.2

68.0

1.46060

1.3440

934.4

695.2

68.1

1.46082

1.3447

936.2

696.2

68.2

1.46106

1.3454

938.0

697.2

68.3

1.46130

1.3460

939.9

698.3

68.4

1.46154

1.3466

941.8

699.4

68.5

1.46178

1.3473

943.7

700.4

68.6

1.46202

1.3479

945.4

701.4

68.7

1.46226

1.3486

947.4

702.5

68.8

1.46251

1.3493

949.2

703.5

68.9

1.46275

1.3499

951.1

704.6

69.0

1.46301

1.3506

953.0

705.6

69.1

1.46323

1.3513

954.8

706.6

69.2

1.46347

1.3519

956.7

707.7

69.3

1.46371

1.3526

958.6

708.7

69.4

1.46396

1.3533

960.6

709.8

69.5

1.46420

1.3539

962.4

710.8

69.6

1.46444

1.3546

964.3

711.9

69.7

1.46468

1.3553

966.2

712.9

69.8

1.46493

1.3560

968.2

714.0

69.9

1.46517

1.3566

970.0

715.0

70.0

1.46544

1.3573

971.8

716.0

70.1

1.46565

1.3579

973.8

717.1

70.2

1.46590

1.3586

975.6

718.1

70.3

1.46614

1.3593

977.6

719.2

70.4

1.46639

1.3599

979.4

720.2

70.5

1.46663

1.3606

981.3

721.2

70.6

1.46688

1.3613

983.3

722.3

70.7

1.46712

1.3619

985.2

723.4

70.8

1.46737

1.3626

987.1

724.4

70.9

1.46761

1.3633

988.9

725.4

71.0

1.46789

1.3639

990.9

726.5

71.1

1.46810

1.3646

992.8

727.5

71.2

1.46835

1.3653

994.8

728.6

71.3

1.46859

1.3659

996.6

729.6

71.4

1.46884

1.3665

998.5

730.7

71.5

1.46908

1.3672

1000.4

731.7

71.6

1.46933

1.3678

1002.2

732.7

71.7

1.46957

1.3685

1004.2

733.8

71.8

1.46982

1.3692

1006.1

734.8

71.9

1.47007

1.3698

1008.0

735.9

72.0

1.47036

1.3705

1009.9

736.9

72.1

1.47056

1.3712

1012.0

738.0

72.2

1.47081

1.3718

1013.8

739.0

72.3

1.47106

1.3725

1015.7

740.0

72.4

1.47131

1.3732

1017.7

741.1

72.5

1.47155

1.3738

1019.5

742.1

72.6

1.47180

1.3745

1021.5

743.2

72.7

1.47205

1.3752

1023.4

744.2

72.8

1.47230

1.3758

1025.4

745.3

72.9

1.47254

1.3765

1027.3

746.3

73.0

1.47284

1.3772

1029.3

747.4

73.1

1.47304

1.3778

1031.2

748.4

73.2

1.47329

1.3785

1033.2

749.5

73.3

1.47354

1.3792

1035.1

750.5

73.4

1.47379

1.3798

1037.1

751.6

73.5

1.47404

1.3805

1039.0

752.6

73.6

1.47429

1.3812

1040.9

753.6

73.7

1.47454

1.3818

1042.8

754.7

73.8

1.47479

1.3825

1044.8

755.7

73.9

1.47504

1.3832

1046.8

756.8

74.0

1.47534

1.3838

1048.6

757.8

74.1

1.47554

1.3845

1050.7

758.9

74.2

1.47579

1.3852

1052.6

759.9

74.3

1.47604

1.3858

1054.6

761.0

74.4

1.47629

1.3865

1056.5

762.0

74.5

1.47654

1.3871

1058.5

763.1

74.6

1.47679

1.3878

1060.4

764.1

74.7

1.47704

1.3885

1062.3

765.1

74.8

1.47730

1.3892

1064.4

766.2

74.9

1.47755

1.3898

1066.3

767.2

75.0

1.47785

1.3905

1068.3

768.3

Table 2 Correction of the Conventional Sugar Mass Titer as a Function of Temperature Mass Titer Measured in %

 

(N.B. : In the French original reproduced here, commas should be replaced with decimal points)

Table 3: Conductivity Corrections for Temperatures Other Than

20oC in μ siemens/cm-1

Temperatures

 

20.2

20.4

20.26

20.8

21.0

21.2

21.4

21.6

21.8

22.0(1)

 

19.8

19.6

19.4

19.2

19.0

18.8

18.6

18.4

18.2

18.0(2)

Conductivity

                   

0

0

0

0

0

0

0

0

0

0

0

50

0

0

1

1

1

1

1

2

2

2

100

0

1

1

2

2

3

3

3

4

4

150

1

1

2

3

3

4

5

5

6

7

200

1

2

3

3

4

5

6

7

8

9

250

1

2

3

4

6

7

8

9

10

11

300

1

3

4

5

7

8

9

11

12

13

350

1

3

5

6

8

9

11

12

14

15

400

2

3

5

7

9

11

12

14

16

18

450

2

3

6

8

10

12

14

16

18

20

500

2

4

7

9

11

13

15

18

20

22

550

2

5

7

10

12

14

17

19

22

24

600

3

5

8

11

13

16

18

21

24

26

(1) Subtract the correction

(2) Add the correction


[1] Modified by resolution OIV-OENO 419A-2011

[2] Modified by resolution OIV-OENO 419A-2011

[3] Modified by resolution OIV-OENO 419A-2011

[4] Modified by resolution OIV-OENO 419A-2011

[5] Modified by resolution OIV-OENO 419A-2011

[6] Modified by resolution OIV-OENO 419A-2011

[7] Modified by resolution OIV-OENO 419A-2011

[8] Modified by resolution OIV-OENO 419A-2011

Oenological tannins

OENOLOGICAL TANNINS

INS N°: 181

OENO 12/2002;

OENO 5/2008;

OENO 6/2008;

OIV/OENO 352/2009;

OIV-OENO 554-2015;

OIV-OENO 574-2017;

OIV-OENO 624-2022

 

1. GENERAL STATEMENTS

Oenological tannins contain polyphenols. Their complex structure is generally made up of a great variety of monomer units that are covalently bound to each other.

These are derived from different parts of plant species and extracted using solvents permitted under current regulations. They are classified into two classes according to the nature of the monomeric units that characterise them: hydrolysable tannins and condensed tannins or proanthocyanic tannins. Besides the two classes of tannins, each monomer unit itself (e.g. flavan-3-ol monomers, gallic acid, ellagic acid) can also occur in tannin preparations.

Hydrolysable tannins form a heterogeneous class that is divided into two sub-classes:

-         gallotannins or gallic tannins consist of a glucose or quinic acid unit that is esterified with one or more molecules gallic acid and/or its depsides.

-         ellagitannins or ellagic tannins consist of glucose unit(s) that is/are esterified with one or more molecules of ellagic acid and related molecules. In addition, the glycosidic unit(s) may be esterified with gallic acid and/or its/their depsides.

The structure of hydrolysable tannins varies according to the degree of esterification and polymerization  (1)

Condensed or proanthocyanic tannins (of the procyanidin and prodelphinidin sub-classes and the profisetinidin and prorobinetidin sub-classes) and consist of polymers of flavan-3-ols. The flavan-3-ol units may differ stereochemically as well as in the degree of hydroxylation and may be present as gallic acid esters. The large variety of monomeric units, different interflavan bonds and the degree of polymerization result in a large number of possible structures of proanthocyanidins. Depending on the molecular structure, the reactivity of proanthocyanidins can vary greatly.

Oenological tannins come exclusively in powder, granule or flake form, from light beige or beige and brick red to dark brown in colour.

They can be dissolved in a portion of must or wine for incorporation into the total amount of must or wine. 

2. LABELLING

The labelling of oenological tannins must specify the following:

  • their botanical origin (e.g. oak, quebracho, etc.),
  • the classes to which they belong (hydrolysable or condensed),
  • the sub-classes (e.g. gallotannins, prodelphinidins, etc.),
  • the batch number and the expiry date,
  • the minimum content of total polyphenols according to the method in Annex 1,
  • the technological functions,
  • when tannin preparations are a mixture of several tannin classes  or tannin sub-classes the different tannin classes  or sub-classes and associated technological functions,
  • the recommended dosage and conditions of use,
  • the storage conditions to guarantee their stability,
  • the possible presence of potentially allergenic residues,
  • where applicable, the indication that the oenological tannins were obtained from genetically-modified plants.

3. PERMITTED OENOLOGICAL TANNINS

The oenological tannins that are described in Chapter 1, that have demonstrable and measurable properties as well as a technological interest duly proven in practice, and that completely fulfil the conditions and criteria mentioned below, are permitted in compliance with the files of the Code of Oenological Practices.

The oenological tannins used should not:

  • liberate substances in concentrations that could lead to potential health risks,
  • cause fraud resulting from the addition of aromas or coloring,
  • be harmful to the quality of the products made,
  • result in the modification of the well-known organoleptic profile of wine (flavouring).

4.  REACTIVITY PROPERTIES AND FUNCTIONS OF OENOLOGICAL TANNINS

4.1 Reactivity

Tannins are likely to be involved in numerous reaction pathways in wine. The reactivity of oenological tannins is directly related to the specific characteristics of their chemical structures; it also depends on the technical operations of production (techniques of extraction, concentration, fractionation, etc.), which influence the polyphenol content (thus the degree of purity) and the proportion of free functional groups. The nature of the plant determines the tannin class(es) or sub-class(es) to which they belong.

4.2 Properties and functions of tannins

The functions of oenological tannins are directly linked to their properties. The methods of analysis used to determine the functions of tannins should correspond to the state of the art and, if possible, be validated according to the appropriate international standards.

The following table lists properties as well as oenological applications, some of which are recognised and some of which remain to be demonstrated.

Theoretical properties

Possible oenological applications

Reactivity with proteins

Clarification aid

Reactivity with oxygen

Antioxidant

Iron chelation

Reduction of iron content

Polymerisation

Colour stabilisation

Formation of complexes

Colour stabilisation

Anti-laccase activity

Inhibition of laccase-activity

Microbiological action

 

Antibacterial effect

Microbiological stability, reduction in SO2 use

The properties and resulting oenological applications will be the object of specific monographs by classes of tannins and/or sub-classes, in which the methods of measurement shall be specified.

4.3 Estimation of the total polyphenol content

The estimation of the total polyphenol content of preparations of oenological tannins is measured by the method described in Annex 1.

The total polyphenol content should be greater than or equal to 65% and a maximum concentration is not required

5. PHYSICAL PROPERTIES

5.1 Insoluble materials

Place 5 g tannin in a solution of 100 mL double-distilled water at room temperature and stir for 15 minutes. After that filter this solution over a 0.8 µm membrane previously weighed. Evaporate and dry the membrane at 100-105 °C. Weight the membrane. The insoluble matter content should not be greater than 5% w/w.

The procedure described later in the total polyphenol content method (Annex 1, point 4.3) could be used as an alternative.

5.2 Loss on drying

Determined up to constant weight, for a 2 g sample, the weight loss in an oven at 100-105 °C for 2 hours should be less than 10%.

6.  MAXIMUM CONTAMINANTS LEVELS

Oenological tannins should be produced in accordance with good manufacturing practices. According to the origin of the plant used, some maximum contaminant levels – such as those for heavy metals – may be different (e.g. the iron content of chestnut-derived tannins).

All of the limits set below relate to dry products.

6.1 Pentachlorophenol

Proceed with determination according to the method described in the OIV Compendium of the International methods of musts and wines. Content should be less than 1 µg/kg.

6.2 Total polycyclic aromatic hydrocarbons (PAH)

Sum of benzo(a)pyrene, benz(a)anthracene, benzo(b)fluoroanthene and chrysene

Proceed with determination according to the method described in Chapter II of the International Oenological Codex. Content should be less than 30 µg/kg.

6.3 Benzo(a)pyrene

Proceed with determination according to the method described in Chapter II of the International Oenological Codex. Content should be less than 5 µg/kg.

6.4 Ashes

Without going above 550 °C, progressively incinerate the residue left by the determination of the loss on drying. The weight of the ashes should be less than 5%. A Higher concentration could mean that the extraction was done with non-authorized solvents.

6.5 Preparation of the test solution

Dissolve the ashes obtained from 2 g tannin into 1 mL diluted hydrochloric acid (R) and a drop of concentrated nitric acid (R). Heat in a water bath at 100 °C for a short time to ensure dissolution is complete. Transfer to a 50-mL calibrated flask, rinsing the capsule with distilled water, and make up to the mark. The test solution is ready to dose following elements.

6.6 Arsenic

For 0.25 g tannin, detect arsenic using the atomic-absorption-spectrophotometry method described in Chapter II of the International Oenological Codex or using ICP/MS according to the method described in the Compendium of International Methods of Wine and Must Analysis, after destruction of the organic matter using the wet method.
The arsenic content should be less than 3 mg/kg.

6.7 Iron

On the basis of 10 mL of test solution prepared according to paragraph 6.5, determine the iron using atomic-absorption-spectrometry according to the method in Chapter II of the International Oenological Codex or using the ICP/MS method described in the Compendium of International Methods of Wine and Must Analysis.

The iron content should be less than 50 mg/kg, with the exception of chestnut-derived tannins, whose iron content should be less than or equal to 200 mg/kg .

6.8 Copper

Proceed with determination according to the method described in Chapter II of the International Oenological Codex or by ICP/MS according to the method described in the Compendium of International Methods of Wine and Must Analysis.
Content should be less than 5 mg/kg.

6.9 Lead

Proceed with determination according to the method described in Chapter II of the International Oenological Codex or by ICP/MS according to the method described in the Compendium of International Methods of Wine and Must Analysis.
Content should be less than 5 mg/kg.

6.10 Mercury

Proceed with determination according to the method described in Chapter II of the International Oenological Codex or by ICP/MS according to the method described in the Compendium of International Methods of Wine and Must Analysis.
Content should be less than 0.5 mg/kg.

6.11 Cadmium

Proceed with determination according to the method described in Chapter II of the International Oenological Codex or by ICP/MS according to the method described in the Compendium of International Methods of Wine and Must Analysis.
Content should be less than 0.5 mg/kg.

6.12 Salmonella

Proceed with counting according to the method described in Chapter II of the International Oenological Codex. Absence should be checked on a 25 g sample of dry matter.

6.13 Total coliforms

Proceed with counting according to the method described in Chapter II of the International Oenological Codex.
Content should be less than 30 CFU/g of dry matter.

6.14 Escherichia coli

Proceed with counting according to the method described in Chapter II of the International Oenological Codex.
Absence should be checked on a 25 g sample of dry matter.

6.15 Moulds

Proceed with counting according to the method described in Chapter II of the International Oenological Codex. Content should be less than 100 CFU/g of dry matter.

(1) Encyclopeadia health food Pub off 00683
Annex 1 METHOD FOR THE ESTIMATION OF THE TOTAL POLYPHENOL CONTENT

  1. PRINCIPLE

This method is designed to measure the concentration in polyphenols of preparations of oenological tannins and is based on gravimetric analysis using solid-phase extraction (SPE). In an SPE column, tannins in aqueous solution are adsorbed onto a polymer (in this case polyvinylpolypyrrolidone) capable of retaining polyphenols. The substances not retained by the PVPP correspond to non-phenolic compounds that were present in the original sample.

The full diagram of the method is presented below:

  1. REAGENTS, MATERIALS AND APPARATUS

2.1 Reagents

  1.        PVPP (approx. 100 µm polyvinylpolypyrrolidone, CAS No. 9003-39-8)
  2.        Aqueous solution of FeCl3 (1 g/L)
  3.        Double-distilled water
  4.        Ethanol (20 % v/v)

2.2 Materials

  1.       Aluminium dishes (70 mL)
  2.       Disposable tubes with a conical base and stoppers (50 mL)
  3.    SPE columns (70 mL reservoir, 150 x 29,75 mm)
  1.     Frits for SPE column (diameter 27 mm, 20 µm PE)
  1.       1 000-mL Pyrex flask
  2.       50-mL Class-A test tubes
  3.       0.45 µm Cellulose acetate membrane filter, Ø 47 mm
  4.       Plastic 50-mL syringe
  5.       25-mL Class-A graduated glass pipettes (2 marks)

2.3 Apparatus

  1. Thermostatic bath at 20 °C
  2. Technical balance with precision of 0.01 g
  1.       Analytical balance with precision of 0.1 mg
  2.       Thermostatic oven at 105 °C
  3.       Thermostatic oven at 80 °C or, failing this, a thermostatic bath
  4.       Centrifuge
  5.       Vacuum manifold

2.3.8 Class-A volumetric glassware

2.3.9 Desiccator

  1. PREPARATION OF SAMPLES

The solution (referred to below as solution A) is used to measure the total solids (TS), soluble solids (SS) and detannised solids (DS).

Weigh approximately 6 g tannins on the analytical balance and make a note of the weight. Dissolve the tannins in around 950 mL hot double-distilled water (60‑70 °C) in a 1-L borosilicate-glass flask and mix well. Leave the flask to rest at room temperature for 30 minutes. Cool the solution at 20‑22 °C in a thermostatic bath, make up to volume with double-distilled water and mix well.

  1. PROCEDURE

4.1 Measurement of total solids (TS)

-          Take a sample and transfer 25 mL of solution A to an aluminium dish (2.2.1),

-          evaporate to dryness in a thermostatic oven at 80 °C,

-          transfer to a thermostatic oven at 105 °C in order to proceed with drying until a constant weight is obtained, then weigh the residue (cool the dish in the desiccator before weighing).

The formula to be applied for the calculation of the total solids (TS) is as follows:

4.2 Measurement of soluble solids (SS)

-          Centrifuge solution A at 10 000 g during 5 minutes,

-          microfilter solution A centrifuged through a membrane filter in order to obtain a clear solution, then leave 25 mL of solution to evaporate to dryness in a thermostatic oven at 80 °C,

-          transfer to a thermostatic oven at 105 °C in order to proceed with drying until a constant weight is obtained, then weigh the residue (cool the dish in the desiccator before weighing).

The formula to be applied for the calculation of soluble solids (SS) is as follows:

4.3 Measurement of insoluble solids (IS)

Calculate the difference between the total solids and soluble solids:

4.4 Measurement of detannised solids (DS)

-          Prepare the SPE columns: introduce the first frit, 7.0 g ± 0.1 g PVPP rehydrated beforehand with a hydro-alcoholic solution at 20% for 15 minutes, as well as the second frit, then pack the stationary phase in well,

-          place the SPE column in a vacuum manifold (example in Figure 1),

-       pack the column with three rinses (do not dry out the PVPP and apply a vacuum of approx. 0.2 bar in order to avoid compacting of the polymer): a first rinse with 50 mL ethanol (20 % v/v), a second rinse with 50 mL double-distilled water, and a third rinse with 20 mL solution A in order to eliminate the water residues of the PVPP,

-          add 30 mL of solution A to the column and collect 30 mL eluate (DS, detannised solids) in a 50-mL Falcon tube with a conical base, interrupting the elution when the liquid reaches the level of the upper frit,

-          take a sample of 25 mL eluate and transfer this into an aluminium dish,

-          leave to evaporate to dryness in a thermostatic oven at 80 °C,

-          transfer to a thermostatic oven at 105 °C in order to proceed with drying until a constant weight is obtained, then weigh the residue (cool the dish in the desiccator before weighing).

The formula to be applied for the calculation of detannised solids (DS) is as follows:

where BC is the value of the blank measured after SPE (see 4.5).

DSC_3773

Figure 1 ‑ Example SPE extraction

In order to guarantee the absence of polyphenols in the eluate after passing through the column, add 3 drops of an aqueous solution of FeCl3 to 3 mL detannised solids (DS) in solution. If the solution develops a blue-black hue, this means that the polyphenols have passed through the polymer; the analysis should then be repeated by reducing the quantity of initial product. If the solution remains colourless after this treatment, proceed with gravimetric analysis.

4.5 Measurement of the blank (BC)

A blank test should be carried out before conducting the SPE elution, in order to evaluate any interference caused by the analytical process. Proceed as follows:

-          prepare the SPE columns: introduce the first frit, 7.0 g ± 0.1 g PVPP rehydrated beforehand with a hydro-alcoholic solution at 20% for 15 minutes, as well as the second frit, then pack in well,

-          place the SPE column in a vacuum manifold (example in Figure 1),

-       pack the column with two rinses (do not dry out the PVPP and apply a vacuum of approx. 0.2 bar in order to avoid compacting of the polymer): a first rinse with 50 mL ethanol (20 % v/v) and a second rinse with 70 mL double-distilled water,

-          add 30 mL double-distilled water to the column and collect 30 mL eluate (blank for detannised solids) in a 50-mL Falcon tube with a conical base, interrupting the elution when the liquid reaches the level of the upper frit,

-          take a sample of 25 mL eluate and transfer this into an aluminium dish, then leave to evaporate to dryness in a thermostatic oven at 80 °C,

-          transfer to a thermostatic oven at 105 °C in order to proceed with drying until a constant weight is obtained, then weigh the residues (cool the dishes in the desiccator before weighing).

  1. EXPRESSION OF RESULTS

Measurement of the percentage of total polyphenols (%polyphenols):

The formula to be applied for the calculation of the percentage is as follows:

-       Determination of the suitability of the PVPP: refer to OENO 11-2002 - COEI-1-PVPP: 2007, § 6.

Procyanidins/ Prodelphinidins tannins

OENOLOGICAL TANNINS

Specific monograph for oenological tannins containing procyanidins/prodelphinidins

(OIV-OENO 675A-2022)

Procyanidins/prodelphinidins are a sub-class of condensed (or proanthocyanic) tannins. Tannins from Vitis vinifera grapes, grape skins and grape seeds are included in this sub-class.

  1.                  Method for the determination of sub-class affiliations

Characterisation by high-performance liquid chromatography (HPLC)

  1.           Principle

This method is designed to verify the presence of characteristic components of condensed tannins of the procyanidin/prodelphinidin sub-class and measure their total concentration. It is applicable to preparations of oenological tannins that are declared as pure and thus as not containing tannins with small masses from different families or sub-classes.

  1.   Reagents, material and apparatus
    1.                    Reagents

 (+)-catechin, CAS No.: 154-23-4

Ultrafiltered water (resistivity: 18.3 MΩ·cm)

Water (HPLC quality)

Methanol (HPLC quality)

Formic acid (HPLC quality)

  1.                    Materials

100-mL borosilicate-glass flask

Cellulose filters with 0.45 µm pore size diameter

Plastic 1-mL syringe

  1.                    Apparatus

Analytical balance with precision of 0.01 g

Analytical balance with precision of 0.1 mg

Class-A volumetric glassware

Mass chromatographic system with spectrometry detection composed of:

-                      Gradient pump for binary or quaternary mix

-                      Injector with a loop of 10 µL

-                      Spectrophotometric detector at 280 nm fixe wavelength

-                      Column Eclipse Plus C-18 (for example): 2.1 x 100 mm, 1.8 µm particle size

-                      ESI-SIM (Selected Ion Monitoring mode via Electro Spray Ionisation) ionisation source

-                      Mass spectrometer detector: quadrupole time of flight (Q-TOF)

  1.   Preparation of samples and standards

Samples: weigh approximately 0.5 g of oenological tannins on the analytical balance and make a note of the weight. Dissolve the oenological tannins in 100 mL of ultrafiltered water in a 100-mL borosilicate-glass flask and mix well.

Preparation of standard solutions: put 10 mg of (+)-catechin in solution into 50 mL of ultrafiltered water, corresponding to a 200 mg/L concentration. Then carry out dilutions in ultrafiltered water to obtain 5, 10, 20, 40, 60, 80 and 100 mg/L concentrations.

Solvent A: HPLC-quality water containing 0.1% of formic acid.

Solvent B: methanol containing 0.1% of formic acid.

  1.   Procedure

The sample solution and standard solutions are filtered on 0.45 µm (pore size diameter) filters and analyse by chromatography under the following conditions:

Injected volume: 10 µL of sample solution or standard solution of (+)-catechin

 Detection at 280 nm

Composition of elution gradient: (time, % of solvent A)

0 min, 99.0%; 0.5 min, 94.0%; 20 min, 50.0%; 25 min, 0.0%; 32 min, 94.0% and 10 min for equilibrium.

Flow rate: 0.3 mL/min

Quantification and detection of the characteristic components of condensed tannins of the procyanidin/prodelphinidin sub-group (sub-class) ((+)-catechin, (-)-epicatechin, (+)gallocatechin, epigallocatechin, (-)-epicatechin-3-O-gallate, (-)-epigallocatechin-3-O-gallate, dimers B1, B2, B3 and B4, B2-3-O-gallate, trimers) according to the ESI-SIM scan and Q-ToF detection, for example.

 

Table 1: Example chemical formulas and masses of the different procyanidins/prodelphinidins

Compound

Chemical formulas

m/z

(+)-catechin

C15H14O6

290.1

(-)-epicatechin

C15H14O6

290.1

(-)-epicatechin-3-O-gallate

C22H18O10

442.1

Dimer B1

C50H26O12

578.1

Dimer B2

C50H26O12

578.1

Dimer B3

C50H26O12

578.1

Dimer B4

C50H26O12

578.1

B2-3-O-gallate

C37H30O16

730.1

Trimers

C45H38O18

866.2

Figure 1: Example of ESI-SIM scan of procyanidins/prodelphinidins

  1.           Conclusion

An oenological tannin is recognised as a procyanidin/prodelphinidin when:

-                      its total polyphenol content is higher than 65% (gravimetric method in Annex 1 of the general monograph OIV-OENO 624-2022),

-                      its procyanidin/prodelphinidin content as characterised by the HPLC method is higher than 120 mg equivalent of (+)-catechin per gram of oenological tannins.

-                       

  1.                  Methods of measurement of properties and functionalities

 

The following compliance methods and criteria are only applicable when the property/functionality is claimed on the preparation of tannins.

 

  1.           Antioxidant ability
    1.   Principle

Determination of procyanidins/prodelphinidins’ ability to contribute to the protection of must and wine from oxidation.

  1.   Products
    1.                    Antioxidant capacity

DPPH (2,2-diphenyl-1-picrylhydrazyl): MM = 394.32

Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid): MM = 250.29

Methanol at 99.9% volume

96-well microplate reader (FLUOstar Omega - BMG Labtech, for example)

  1.                    Direct oxygen consumption (OCR)

Ethanol at 96% volume, CAS No. 64-17-5

Tartaric acid: MM = 150.09, CAS No. 87-69-4

Iron (III) chloride hexahydrate: MM = 270.30, CAS No. 7705-08-0

Copper (II) sulfate pentahydrate: MM = 249.68, CAS No. 7758-98-7

Clear glass bottles with inserted pills of 0.75-cL capacity

NomaSens oximeter, for example

  1.   Protocols
    1.                    Antioxidant capacity (DPPH assay)

0.15 g/L oenological tannin solution: dissolve 37.5 mg of oenological tannins in 500 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5). Dilution of oenological tannins solution could be needed if the measurement absorbance is higher than 1 unit (in this case the dilution should be included in the calculation).

1mM Trolox solution: dissolve 125 mg of Trolox in 500 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

Calibration curve:  dissolve in 1, 0.8, 0.6, 0.4, 0.2 and 0.1 mL of 1mM Trolox solution into 0, 0.2, 0.4, 0.6, 0.8 and 0.9 mL of model wine solution. These quantities correspond to 1, 0.8, 0.6, 0.4, 0.2 and 0.1 mM final concentration of Trolox respectively.

6.10-5 M DPPH solution: dissolve 2.36 mg of DPPH in 100 mL of methanol. The solution should be freshly prepared.

  1.                    Direct oxygen consumption (OCR)

1 g/L oenological tannin solution: dissolve 0.75 g of oenological tannins in 750 mL of model wine solution.

Model wine solution: dissolve 4 g of tartaric acid, 2.25 mg of Iron (III) chloride hexahydrate and 0.225 mg of Copper (II) sulfate pentahydrate in 90 mL of ethanol and 660 mL of distilled water. The pH should be adjusted at 3.5.

  1.   Tests
    1.                    Antioxidant capacity

First a blank containing solely the DPPH reagent (RB) is measured at 515 nm by placing 190 µL of DPPH solution (1.3.1) in all the wells of the plate. Then, add 10 µL of oenological tannin solution (samples), distilled water (blank) or Trolox curve solution (standards) into the wells and measure (MS) at 515 nm after 30 min.

See Figure 2 for an example of how to fill the plate.

The formula to be applied for the calculation of the antioxidant capacity is as follows:

  1.                 
  2.                 

where “a” and “b” correspond respectively to the slope and the constant of the Trolox calibration curve: Absorbance = f ([Trolox])  Absorbance = ax + b

In all cases, procyanidins/prodelphinidins should demonstrate antioxidant capacity, and more specifically they should have more than 500 ± 50 mg equivalent Trolox per gram of tannins (commercial extract).

Figure 2: example 96-well plate

  1.                    Direct oxygen consumption (OCR)

First the model wine solution is saturated with oxygen at 8 mg/L by bubbling with air for 10 min at 20-25 °C. Then, add the oenological tannins to the model wine solution in the bottles filled to 0.75 cL. Seal the bottles hermetically and shake to fully homogenise.

  1.               Measure the oxygen consumed every two days starting 1h after the filled of the bottles.
  2.               To determine the oxygen consumption rate, follow the pathway as shown in Figure 2
    •                  represent the oxygen consumption versus the time,
    •                  then represent the inverse of the oxygen consumed versus the inverse of the time,
    •                  the oxygen consumption rate corresponds to the inverse of the slope coefficient:
      •                  OCR t0 mg of O2 consumed per day and per g of tannins = 1/A, A being the slope coefficient

 

 

In all cases, procyanidins/prodelphinidins should demonstrate an ability to consume the oxygen directly, and more specifically they should be able to consume at least 0.10 ± 0.05 mg of O2 per litre, per day and per gram of tannins (commercial extract).

 

 

 

Figure 3: Pathway to determine oxygen consumption rate

  1.                    Antioxidasic ability
    1.             Principle

Determination of procyanidins/prodelphinidins’ antioxidasic ability to contribute to antioxidasic protection in terms of the laccase activity of compounds in must and wine.

  1.             Products

Ethanol at 96% volume, CAS No. 64-17-5

Tartaric acid: MM = 150.09, CAS No. 87-69-4

Sodium acetate: MM = 82.03, CAS No. 6131-90-4

Syringaldazine (4-hydroxy-3,5-dimethoxybenzaldehyde azine): MM = 360.36, CAS No. 14414-32-5

Polyvinylpolypyrrolidone (PVPP): CAS No. 25249-54-1

Must botrytised with laccase activity

Distilled water (HPLC quality)

  1.             Protocols

2 g/L oenological tannin solution: dissolve 200 mg of oenological tannins in 100 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

Buffer solution (8.2 g/L): dissolve 410 mg of sodium acetate in 50 mL of distilled water.

Syringaldazine solution (0.06 g/L): dissolve 30 mg of syringaldazine in 500 mL of ethanol.

  1.                    Tests
  1.                  Add 4 mL of botrytised must to 1 mL of oenological tannin solution in one tube, which will correspond to sample modality.
  2.                  Add 4 mL of botrytised must to 1 mL of model wine solution in one tube, which will correspond to control modality.
  3.                  After 4 minutes (precisely), add 0.8 g of PVPP to both tubes (sample and control modalities), stir and centrifuge for 10 minutes at 8,500 rpm.
  4.                  Recover 1 mL of the supernatant (for both sample and control modalities), into 1.4 mL of buffer solution and 0.6 mL of syringaldazine solution. Put the mixture into a plastic spectrophotometer cuvette (10 mm path length).
  5.                  Measure the absorbance at 530 nm every minute for 5 minutes (including time measurements at 0 minutes).
  6.                  Then determine the laccase activity and the residual laccase activity by using the following equations and Figure 3:
  7.                   

𝐿𝑎𝑐𝑐𝑎𝑠𝑒 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦 = 46.15 𝑥 Δ𝐴 µ𝑚𝑜𝑙. 𝐿−1. 𝑚𝑖𝑛−1 = 46.15 𝑥 Δ𝐴 𝑈𝐿

% 𝑜𝑓 𝑟𝑒𝑠𝑖𝑑𝑢𝑎𝑙 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦 = (𝑙𝑎𝑐𝑐𝑎𝑠𝑒 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦𝑠𝑎𝑚𝑝𝑙𝑒/ 𝑙𝑎𝑐𝑐𝑎𝑠𝑒 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦𝑐𝑜𝑛𝑡𝑟𝑜𝑙) 𝑥 100

Figure 4: Example determination of .

In all cases, procyanidins/prodelphinidins should demonstrate an antioxidasic ability, and more specifically they should be able to reduce the residual laccase activity by at least 50%. This value is valuable for must and wine containing less than 5 UL (units of laccases).

  1.   Colour stabilisation
    1.                    Principle

Determination of procyanidin/prodelphinidin colour stabilisation properties to promote the expression, stabilisation and preservation of colour in red must and wine.

  1.                    Products

Ethanol at 96% volume, CAS No. 64-17-5

Tartaric acid: MM = 150.09, CAS No. 87-69-4

Malvidin-3-O-glucoside: MM = 528.87, CAS No. 18470-06-9

  1.                    Protocols

0.8 g/L oenological tannin solution: dissolve 80 mg of oenological tannins in 100 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

0.1 g/L malvidin-3-O-glucoside solution: dissolve 10 mg of malvidin-3-O-glucoside in 100 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

  1.                    Tests
  1.                  Place 0.75 mL of oenological tannin solution and 0.75 mL of model wine solution in one 2-mL stoppered conical tube – hereinafter a “tube” – and keep it in the dark at room temperature. This tube will be called “T0”.
  2.                  Place 0.75 mL of malvidin-3-O-glucoside solution and 0.75 mL of model wine solution in one tube and keep it in the dark at room temperature. This tube will be called “M”.
  3.                  Place 0.75 mL of oenological tannin solution and 0.75 mL of malvidin solution in one tube and keep it in the dark at room temperature. This tube will be called “TM”.
  4.                  After 7 days, measure the absorbance at 450, 520, 570 and 630 nm of the three tubes (TM, T0 and M).
  5.                  Subtract the absorbance values of T0 to TM to obtain the absorbance, taking into account the absorbances of the oenological tannins used.

A(TM) – A(T0) = A(T)

  1.                  Then, determine the CIELAB coordinates (L*, a* and b*) corresponding to the tannin solution with malvidin-3-O-glucoside (T) and malvidin-3-O-glucoside solution (M) with the free MSCV software (https://www.unirioja.es/color/descargas.shtml) or equivalent.

The formulas to be applied for the calculation of the copigmentation index are as follows:

ΔEab.TS: total colour difference between the solution of malvidin-3-O-glucoside containing commercial tannins (T) and a pure white colour solution (W).

ΔEab.CS: total colour difference between the solution of malvidin-3-O-glucoside (M) and a pure white colour solution (W).

The CIELAB coordinates of a pure white colour solution are L* = 100.00, a* = 0.00 and b* = 0.00.

In all cases, procyanidins/prodelphinidins should demonstrate an ability to stabilise the colour, and more specifically their copigmentation index should read as higher than 7.0 ± 2.0% after 7 days.

 

Note: Alternative methods of determination can be used in place of any of the methods described, on the condition that these have been internally validated.

 

 

  1.                  Bibliography
  •                   Sarneckis, C.J.; Dambergs, R.G.; Jones, P.; Mercurio, M.; Herderich, M.J.; Smith, P.A. Quantification of condensed tannins by precipitation with methyl cellulose: development and validation of an optimised tool for grape and wine analysis. Australian Journal of Grape Wine Research 2006, 12, 39–49.
  •                   Vignault, A.; González-Centeno, M.R.; Pascual, O.; Gombau, J.; Jourdes, M.; Moine, V.; Iturmendi, N.; Canals, J.M.; Zamora, F.; Teissedre, P.-L. Chemical characterization, antioxidant properties and oxygen consumption rate of 36 commercial oenological tannins in a model wine solution. Food Chemistry 2018, 268, 210–219.
  •                   Vignault, A.; Pascual, O.; Jourdes, M.; Moine, V.; Fermaud, M.; Roudet, J.; Canals, J.M.; Teissedre, P.-L.; Zamora, F. Impact of enological tannins on laccase activity. OENO One 2019, 53, 27–38.
  •                   Vignault, A.; Pascual, O.; Gombau, J.; Jourdes, M.; Moine, V.; Canals, J.M.; Teissedre, P.-L.; Zamora, F. Recent advances of the OIV working group on oenological tannins in the study of the functionalities of oenological. BIO Web of Conferences 2019, 15, 02015.
  •                   Vignault, A.; Gombau, J.; Pascual, O.; Jourdes, M.; Moine, V.; Canals, J.M.; Zamora, F.; Teissedre, P.-L. Copigmentation of Malvidin-3-O-Monoglucoside by Oenological Tannins: Incidence on Wine Model Color in Function of Botanical Origin, pH and Ethanol Content. Molecules 2019, 24, 1–15.
  •                   Vignault, A.; Gombau, J.; Jourdes, M.; Moine, V.; Canals, J.M.; Fermaud, M.; Roudet, J.; Zamora, F.; Teissedre, P.-L. Oenological tannins to prevent Botrytis cinerea damage in grapes and musts: kinetics and electrophoresis characterization of laccase. Food Chemistry 2020, 316, 126334.
  •                   Vignault, A. Tanins œnologiques : caractéristiques, propriétés et fonctionnalités. Impact sur la qualité des vins. Thèse de doctorat, Université de Bordeaux et Universitat Rovira i Virgili, 2019.

 

Ellagitannins

OENOLOGICAL TANNINS

Specific monograph for oenological tannins containing ellagitannins

OIV-OENO 675B-2022

Ellagitannins are a sub-class of hydrolysable tannins. Chestnut and oak tree tannins are included in this sub-class.

  1.                  Method for the determination of sub-class affiliations
    1.           Characterisation by high-performance liquid chromatography (HPLC)
      1.   Principle

This method is designed to verify the presence of ellagitannins in oenological tannins and measure their total concentration.

  1.   Reagents, materials and apparatus
    1.                    Reagents

Vescalagin (purity > 96%), CAS No. 36001-47-5

Ultrafiltered water (resistivity: 18.3 MΩ·cm)

Water (HPLC quality)

Methanol (HPLC quality)

Formic acid (HPLC quality)

  1.                    Materials

100-mL borosilicate-glass flask

Cellulose filters with 0.45 µm pore size diameter

Plastic 1-mL syringe

  1.                    Apparatus

Technical balance with precision of 0.01 g

Analytical balance with precision of 0.1 mg

Class-A volumetric glassware

Mass chromatographic system with spectrometry detection composed of:

-                      Gradient pump for binary or quaternary mix

-                      Injector with a loop of 10 µL

-                      Spectrophotometric detector at 280 nm fixe wavelength

-                      Column Phenomenex Kinetex (for example): 150 x 3.0 mm, 2.6 µm particle size

-                      ESI-SIM (Single Ion Monitoring mode via Electro Spray Ionisation) ionisation source

-                      Mass spectrometer detector: triple quadrupole time of flight (Q-Tof)

  1.   Preparation of samples and standards

Samples: weigh approximately 0.5 g of oenological tannin on the analytical balance and make a note of the weight. Dissolve the oenological tannin in 100 mL of ultrafiltered water in a 100-mL borosilicate-glass flask and mix well.

Preparation of standard solutions: put 10 mg of vescalagin in solution into 50 mL of ultrafiltered water, corresponding to a 200 mg/L concentration. Then carry out dilutions in ultrafiltered water to obtain 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 40, 50 and 100 mg/L concentrations for the calibration curve.

Solvent A: water (HPLC quality) containing 0.1% of formic acid (HPLC quality).

Solvent B: methanol containing 0.1% of formic acid (HPLC quality).

  1.   Procedure

Oenological tannin solution and standard solutions are filtered on 0.45 µm (pore size diameter) filters and analyse by chromatography under the following conditions given by way of example:

 Injected volume: 10 µL of oenological tannin solution or standard solution of vescalagin

 Detection at 280 nm

Composition of elution gradient: (time, % of solvent A)

0min, 99.0%; 2 min, 98.0%; 5 min, 97.0%; 6 min, 96.5%; 7 min, 96.0%; 8 min, 95.5%; 10 min, 95.0%; 14 min, 90.0%; 17 min, 85.0%; 23 min, 80%; 35 min, 1.0% and 10 min for equilibrium.             

Flow rate: 0.4 mL/min

Quantification and detection of the eight principal ellagitannins (vescalagin, castalagin, roburin A, B, C, D, E and grandinin) according to DAD (UV 280 nm) or the ESI-SIM scan with Q-ToF detection, which allows for more precise detection and quantification.

Figure 1: Example ellagitannin chromatogram at 280 nm

  1.           Conclusion

An oenological tannin is recognised as an ellagitannin (or ellagic tannin) when:

-                      its total polyphenol content is higher than 65% (gravimetric method in Annex 1 of the general monograph OIV-OENO 624-2022),

-                      its ellagitannin content is higher than 200 mg equivalent gallic acid per gram of oenological tannins (characterised by the HPLC method).

  1.                  Methods of measurement of properties and functionalities

 

The following compliance methods and criteria are only applicable when the property/functionality is claimed on the preparation of tannins.

 

 

  1.           Antioxidant ability
    1.   Principle

Determination of ellagitannins’ antioxidant ability to contribute to the protection of must and wine from oxidation.

  1.   Products
    1.                    Antioxidant capacity

DPPH (2,2-diphenyl-1-picrylhydrazyl): MM = 394.32

Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid): MM = 250.29

Methanol at 99.9% volume

96-well microplate reader (FLUOstar Omega - BMG Labtech, for example)

  1.                    Direct oxygen consumption (OCR)

Ethanol at 96% volume, CAS No. 64-17-5

Tartaric acid: MM = 150.09, CAS No. 87-69-4

Iron (III) chloride hexahydrate: MM = 270.30, CAS No. 7705-08-0

Copper (II) sulfate pentahydrate: MM = 249.68, CAS No. 7758-98-7

Clear glass bottles with inserted pills of 0.75-L capacity

NomaSens oximeter (for example)

  1.   Protocols
    1.                    Antioxidant capacity (DPPH assay)

0.15 g/L oenological tannin solution: dissolve 37.5 mg of oenological tannins in 500  mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5). Dilution of oenological tannins solution could be needed if the measurement absorbance is higher than 1 unit (in this case the dilution should be included in the calculation).

1mM Trolox solution: dissolve 125 mg of Trolox in 500 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

Calibration curve:  dissolve in 1, 0.8, 0.6, 0.4, 0.2 and 0.1 mL of 1mM Trolox solution into 0, 0.2, 0.4, 0.6, 0.8 and 0.9 mL of model wine solution. These quantities correspond to 1, 0.8, 0.6, 0.4, 0.2 and 0.1 mM final concentration of Trolox respectively.

6.10-5 M DPPH solution: dissolve 2.36 mg of DPPH in 100 mL of methanol. The solution should be freshly prepared.

  1.                    Direct oxygen consumption (OCR)

1 g/L oenological tannin solution: dissolve 0.75 g of oenological tannins in 750 mL of model wine solution.

Model wine solution: dissolve 4 g of tartaric acid, 2.25 mg of Iron (III) chloride hexahydrate and 0.225 mg of Copper (II) sulfate pentahydrate in 90 mL of ethanol and 660 mL of distilled water. The pH should be adjusted at 3.5.

  1.   Tests
    1.                    Antioxidant capacity

First a blank containing solely the DPPH reagent (RB) is measured at 515 nm by placing 190 µL of DPPH solution (1.3.1) in all the wells of the plate. Then, add 10 µL of oenological tannin solution (samples), distilled water (blank) or Trolox curve solution (standards) into the wells and measure (MS) at 515 nm after 30 min.

See Figure 2 for an example of how to fill the plate.

The formula to be applied for the calculation of the antioxidant capacity is as follows:

  1.                 
  2.                 

where “a” and “b” correspond respectively to the slope and the constant of the Trolox calibration curve: Absorbance = f ([Trolox])  Absorbance = ax + b

 

In all cases, ellagitannins (or ellagic tannins) should demonstrate an antioxidant capacity, and more specifically they should have more than 600 ± 50 mg equivalent Trolox per gram of tannins (commercial extract).

Figure 2: example 96-well plate

 

  1.                    Direct oxygen consumption (OCR)

First the model wine solution is saturated with oxygen at 8 mg/L by bubbling with air for 10 min at 20-25 °C. Then, add the oenological tannins to the model wine solution in the bottles filled to 0.75 cL. Sealed the bottles hermetically and shake to fully homogenise.

  1.               Measure the oxygen consumed every two days starting 1h after the filled of the bottles.
  2.               To determine the oxygen consumption rate, follow the pathway as shown in Figure 2
    •                   represent the oxygen consumption versus the time,
    •                   then represent the inverse of the oxygen consumed versus the inverse of the time,
    •                   the oxygen consumption rate corresponds to the inverse of the slope coefficient:

OCR t0 mg of O2 per L consumed per day and per g of tannins = 1/A, A being the slope coefficient

In all cases, ellagitannins (or ellagic tannins) should demonstrate an ability to consume the oxygen directly, and more specifically they should be able to consume at least 0.50 ± 0.05 mg of O2 per litre, per day and per gram of tannins (commercial extract).

 

 

Figure 3: Pathway to determine oxygen consumption rate

  1.           Antioxidasic ability
    1.   Principle

Determination of ellagitannins’ antioxidasic ability to contribute to antioxidasic protection in terms of the laccase activity of compounds in must and wine.

  1.   Products

Ethanol at 96% volume, CAS No. 64-17-5

Tartaric acid: MM = 150.09, CAS No. 87-69-4

Sodium acetate: MM = 82.03, CAS No. 6131-90-4

Syringaldazine (4-hydroxy-3,5-dimethoxybenzaldehyde azine): MM = 360.36, CAS No. 14414-32-5

Polyvinylpolypyrrolidone: PVPP, CAS No. 25249-54-1

Must botrytised with laccase activity

Distilled water (HPLC quality)

  1.   Protocols

2 g/L oenological tannin solution: dissolve 200 mg of oenological tannins in 100 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

Buffer solution (8.2 g/L): dissolve 410 mg of sodium acetate in 50 mL of distilled water.

Syringaldazine solution (0.06 g/L): dissolve 30 mg of syringaldazine in 500 mL of ethanol.

  1.   Tests
  1.                  Add 4 mL of botrytized must to 1 mL of oenological tannin solution in tube, which will correspond to sample modality.
  2.                  Add 4 mL of botrytized must to 1 mL of model wine solution in tube, which will correspond to control modality.
  3.                  After 4 minutes (precisely), add 0.8 g of PVPP in both tube (sample and control modalities), stirred and centrifuged for 10 minutes at 8,500 rpm.
  4.                  Recover 1 mL of the supernatant (for both sample and control modalities), into 1.4 mL of buffer solution and 0.6 mL of syringaldazine solution. Put the mixture into a plastic spectrophotometer cuvette (10 mm path length).
  5.                  Measure the absorbance at 530 nm every minute for 5 minutes (including time measurements at 0 minutes).
  6.                  Then determine the laccase activity and the residual laccase activity by using the following equations and Figure 3:

𝐿𝑎𝑐𝑐𝑎𝑠𝑒 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦 = 46.15 𝑥 Δ𝐴 µ𝑚𝑜𝑙. 𝐿−1. 𝑚𝑖𝑛−1 = 46.15 𝑥 Δ𝐴 𝑈𝐿

% 𝑜𝑓 𝑟𝑒𝑠𝑖𝑑𝑢𝑎𝑙 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦 = (𝑙𝑎𝑐𝑐𝑎𝑠𝑒 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦𝑠𝑎𝑚𝑝𝑙𝑒/ 𝑙𝑎𝑐𝑐𝑎𝑠𝑒 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦𝑐𝑜𝑛𝑡𝑟𝑜𝑙) 𝑥 100

Figure 4: Example determination of .

In all cases, ellagitannins (or ellagic tannins) should demonstrate an antioxidasic ability, and more specifically they should be able to reduce the residual laccase activity by at least 40%. This value is valuable for must and wine containing less than 5 UL (units of laccases).

 

  1.           Colour stabilization
    1.   Principle

Determination of ellagitannins’ colour stabilisation properties to promote the expression, stabilisation and preservation of colour in red must and wine.

  1.   Products

Ethanol at 96% volume, CAS No. 64-17-5

Tartaric acid: MM = 150.09, CAS No. 87-69-4

Malvidin-3-O-glucoside: MM = 528.87, CAS No. 18470-06-9

  1.   Protocols

0.8 g/L oenological tannin solution: dissolve 80 mg of oenological tannins in 100 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

0.1 g/L malvidin-3-O-glucoside solution: dissolve 10 mg of malvidin-3-O-glucoside in 100 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

  1.   Tests
  1.                  Place 0.75 mL of oenological tannin solution and 0.75 mL of model wine solution in one  2-mL stoppered conical tube – hereinafter a “tube” – and keep it in the dark at room temperature. This tube will be called “T0”.
  2.                  Place 0.75 mL of malvidin-3-O-glucoside solution and 0.75 mL of model wine solution in one tube and keep it in the dark at room temperature. This tube will be called “M”.
  3.                  Place 0.75 mL of oenological tannin solution and 0.75 mL of malvidin solution in one tube and keep it in the dark at room temperature. This tube will be called “TM”.
  4.                  After 7 days, measure the absorbance at 450, 520, 570 and 630 nm of the three tubes (TM, T0 and M).
  5.                  Subtract the absorbance values of T0 to TM to obtain the absorbance avoiding the interferences due to the “natural” colour of the oenological tannin.

A(TM) – A(T0) = A(T)

  1.                  Then, determine the CIELAB coordinates (L*, a* and b*) corresponding to the tannin solution with malvidin-3-O-glucoside (T) and malvidin-3-O-glucoside solution (M) with the free MSCV software (https://www.unirioja.es/color/descargas.shtml) or equivalent.

The formulas to be applied for the calculation of the copigmentation index are as follows:

ΔEab.TS: total colour difference between the solution of malvidin-3-O-glucoside containing commercial tannins (T) and a pure white colour solution (W).

ΔEab.CS: total colour difference between the solution of malvidin-3-O-glucoside (M) and a pure white colour solution (W).

The CIELAB coordinates of a pure white colour solution are L* = 100.00, a* = 0.00 and b* = 0.00.

In all cases, ellagitannins (or ellagic tannins) should demonstrate an ability to stabilise the colour, and more specifically their copigmentation index should read as higher than 10.0 ± 2.0% after 7 days.

 

Note: Alternative methods of determination can be used in place of any of the methods described, on the condition that these have been internally validated.

 

  1.                  Bibliography
  •                   Sarneckis, C.J.; Dambergs, R.G.; Jones, P.; Mercurio, M.; Herderich, M.J.; Smith, P.A. Quantification of condensed tannins by precipitation with methyl cellulose: development and validation of an optimised tool for grape and wine analysis. Australian Journal of Grape Wine Research 2006, 12, 39–49.
  •                   Vignault, A.; González-Centeno, M.R.; Pascual, O.; Gombau, J.; Jourdes, M.; Moine, V.; Iturmendi, N.; Canals, J.M.; Zamora, F.; Teissedre, P.-L. Chemical characterization, antioxidant properties and oxygen consumption rate of 36 commercial oenological tannins in a model wine solution. Food Chemistry 2018, 268, 210–219.
  •                   Vignault, A.; Pascual, O.; Jourdes, M.; Moine, V.; Fermaud, M.; Roudet, J.; Canals, J.M.; Teissedre, P.-L.; Zamora, F. Impact of enological tannins on laccase activity. OENO One 2019, 53, 27–38.
  •                   Vignault, A.; Pascual, O.; Gombau, J.; Jourdes, M.; Moine, V.; Canals, J.M.; Teissedre, P.-L.; Zamora, F. Recent advances of the OIV working group on oenological tannins in the study of the functionalities of oenological. BIO Web of Conferences 2019, 15, 02015.
  •                   Vignault, A.; Gombau, J.; Pascual, O.; Jourdes, M.; Moine, V.; Canals, J.M.; Zamora, F.; Teissedre, P.-L. Copigmentation of Malvidin-3-O-Monoglucoside by Oenological Tannins: Incidence on Wine Model Color in Function of Botanical Origin, pH and Ethanol Content. Molecules 2019, 24, 1–15.
  •                   Vignault, A.; Gombau, J.; Jourdes, M.; Moine, V.; Canals, J.M.; Fermaud, M.; Roudet, J.; Zamora, F.; Teissedre, P.-L. Oenological tannins to prevent Botrytis cinerea damage in grapes and musts: kinetics and electrophoresis characterization of laccase. Food Chemistry 2020, 316, 126334.
  •                   Vignault, A. Tanins œnologiques : caractéristiques, propriétés et fonctionnalités. Impact sur la qualité des vins. Thèse de doctorat, Université de Bordeaux et Universitat Rovira i Virgili, 2019.

Gallic tannins

OENOLOGICAL TANNINS

Specific monograph for preparations containing
gallic tannins

OIV-OENO 675C-2022

Gallotannins, or gallic tannins, are a sub-class of hydrolysable tannins. Oak (and chestnut) galls  and tara (Caesalpinia spinosa) pod tannins are included in this sub-class.

  1.                   Method for the determination of sub-class affiliations

 

  1.              Characterisation by high-performance liquid chromatography (HPLC)
    1.        Principle

This method is designed to verify the presence of gallotannins and measure their total concentration.

  1.        Reagents, materials and apparatus
    1. Reagents

Gallic acid (purity > 96%), CAS No. 149-91-7

Ultrafiltered water (resistivity: 18.3 MΩ·cm)

Water (HPLC grade)

Methanol (HPLC grade)

Formic acid (HPLC grade)

  1. Materials

100-mL borosilicate-glass flask

Filters with 0.45 µm pore size diameter

Plastic 1-mL syringe

  1. Apparatus

Technical balance with precision of ± 0.01 g

Analytical balance with precision of ± 0.1 mg

Class-A volumetric glassware

Mass chromatographic system with detection by spectrometry composed of:

-                      Gradient pump for binary or quaternary mix

-                      Injector fitted with a loop of 10 µL

-                      Spectrophotometric detector at 280 nm fixe wavelength

-                      Column Phenomenex Kinetex (for example): 150 x 3.0 mm, 2.6 µm particle size

-                      ESI-SIM (Single Ion Monitoring mode via Electro Spray Ionisation) ionisation source

-                      Mass spectrometer detector: triple quadrupole time of flight (Q-ToF)

  1.        Preparation of samples and standards

Samples: weigh approximately 0.5 g of oenological tannins on the analytical balance and make a note of the weight. Dissolve the oenological tannins in 100 mL of ultrafiltered water in a 100-mL borosilicate-glass flask and mix well.

Preparation of standard solutions: put 10 mg of gallic acid in solution into 50 mL of ultrafiltered water, corresponding to a 200 mg/L concentration. Then carry out dilutions in ultrafiltered water to obtain 1, 5, 10, 25, 50, 75 and 100 mg/L concentrations.

Solvent A: HPLC-quality water containing 0.1% of formic acid.

Solvent B: methanol containing 0.1% of formic acid.

  1.        Procedure

Sample solution and standard solutions are filtered on 0.45 µm (pore size diameter) cellulose filters and analyse by chromatography under the following conditions given by way of example:

 Injected volume: 10 µL of sample solution or standard solution of gallic acid

 Detection at 280 nm

Composition of elution gradient: (time, % of solvent A)

0min, 99.0%; 2 min, 98.0%; 5 min, 97.0%; 6 min, 96.5%; 7 min, 96.0%; 8 min, 95.5%; 10 min, 95.0%; 14 min, 90.0%; 17 min, 85.0%; 23 min, 00%; 25 min, 8.0%; 29 min, 5.0%; 34 min, 1.0%; 45 min, 99.0% and 10 min for equilibrium.

Flow rate: 0.4 mL/min

Quantification and detection of the components of the following gallic tannins: gallic, digallic and quinic acid; 3-, 4- and 5-galloylquinic acid; tri-, tetra-, penta-, hexa-, hepta-, octa-, nona- and decagalloyl-glucose according to the ESI-SIM scan and Q-ToF detection (for example).

Table 1: Example chemical formulas and m/z of the different gallotannins (or gallic tannins)

Compounds

Chemical formula

m/z

Gallic acid

C7H6O5

170.0

Digallic acid

C14H10O9

322.2

Quinic acid

C7H12O6

192.2

3-galloylquinic acid

C28H24O18

648.1

4-galloylquinic acid

C35H28O22

800.1

5-galloylquinic acid

C42H32O26

952.7

Trigalloyl glucose

C27H24O18

636.5

Tetragalloyl glucose

C24H28O22

788.6

Pentagalloyl glucose

C41H32O26

940.6

Hexagalloyl glucose

C48H36O30

1092.8

Heptagalloyl glucose

C55H40O34

1244.9

Octagalloyl glucose

C62H44O38

1396.9

Nonagalloyl glucose

C69H48O42

1548.1

Decagalloyl glucose

C76H52O46

1707.2

Figure 1: Example ESI-SIM scan of gallotannins (or gallic tannins)

 

  1.              Conclusion

 

An oenological tannin is recognised as a gallotannin (or gallic tannin) when:

-                      its total phenol content is higher than 65% (gravimetric method in Annex 1 of the general monograph OIV-OENO 624-2022),

-                      its gallotannin content as characterised by the HPLC method is higher than 190 mg equivalent of gallic acid per gram of oenological tannins.

  1.                   Properties and functionalities

 

The following compliance methods and criteria are only applicable when the property/functionality is claimed on the preparation of tannins.

 

  1.              Antioxidant ability
    1.        Principle

Determination of gallotannins’ antioxidant ability to contribute to the protection of must and wine from oxidation.

  1.        Products
    1. Antioxidant capacity

DPPH (2,2-diphenyl-1-picrylhydrazyle): MM = 394.32

Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid): MM = 250.29

Methanol at 99.9% volume

96-well microplates reader (FLUOstar Omega - BMG Labtech, for example)

  1. Direct oxygen consumption (OCR)

Ethanol at 96% volume, CAS No. 64-17-5

Tartaric acid: MM = 150.09, CAS No. 87-69-4

Iron (III) chloride hexahydrate: MM = 270.30, CAS No. 7705-08-0

Copper (II) sulfate pentahydrate: MM = 249.68, CAS No. 7758-98-7

Clear glass bottles with inserted pills of 0.75-cL capacity

NomaSens oximeter, for example

  1.        Protocols
    1. Antioxidant capacity (DPPH assay)

0.15 g/L oenological tannin solution: dissolve 37.5 mg of oenological tannins in 500 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5). Dilution of oenological tannins solution could be needed if the measurement absorbance is higher than 1 unit (in this case the dilution should be included in the calculation).

1mM Trolox solution: dissolve 125 mg of Trolox in 500 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

Calibration curve:  dissolve in 1, 0.8, 0.6, 0.4, 0.2 and 0.1 mL of 1 mM Trolox solution into 0, 0.2, 0.4, 0.6, 0.8 and 0.9 mL of model wine solution. These quantities correspond to 1, 0.8, 0.6, 0.4, 0.2 and 0.1 mM final concentration of Trolox respectively.

6.10-5 M DPPH solution: dissolve 2.36 mg of DPPH in 100 mL of methanol. The solution should be freshly prepared.

  1. Direct oxygen consumption (OCR)

1 g/L oenological tannin solution: dissolve 0.75 g of oenological tannin in 750 mL of model wine solution.

Model wine solution: dissolve 4 g of tartaric acid, 2.25 mg of Iron (III) chloride hexahydrate and 0.225 mg of Copper (II) sulfate pentahydrate in 90 mL of ethanol and 660 mL of distilled water. The pH should be adjusted at 3.5.

  1.        Tests
    1. Antioxidant capacity

First a blank containing solely reagent (RB) is measure at 515 nm by placing 190 µL of DPPH solution (1.3.1) in all the wells of the plate. Then, add 10 µL of oenological tannin solution (samples), distilled water (blank) or Trolox curve solution (standards) into the wells and measure (MS) at 515 nm after 30 min.

See Figure 2 for an example of how to fill the plate.

The formula to be applied for the calculation of the antioxidant capacity is as follows:

  1.                  
  2.                  

where “a” and “b” correspond respectively to the slope and the constant of the Trolox calibration curve: Absorbance = f ([Trolox])  Absorbance = ax + b

In all cases, gallotannins (or gallic tannins) should demonstrate antioxidant capacity, and more specifically they should have more than 600 ± 50 mg equivalent Trolox per gram of tannins (commercial extract).

Figure 2: Example 96-well plate

  1. Direct oxygen consumption (OCR)

First the model wine solution is saturated with oxygen at 8 mg/L by bubbling with air for 10 min at 20-25 °C. Then, add the oenological tannins to the model wine solution in the bottles filled to 0.75 cL. Seal the bottles hermetically and shake to fully homogenise.

  1.                Measure the oxygen consumed every two days starting 1h after the filled of the bottles.
  2.                To determine the oxygen consumption rate, follow the pathway as shown in Figure 2
    •                  represent the oxygen consumption versus the time,
    •                  then represent the inverse of the oxygen consumed versus the inverse of the time,
    •                  the oxygen consumption rate corresponds to the inverse of the slope coefficient:

OCR t0 mg of O2 per L consumed per day and per g of tannins = 1/A, A being the slope coefficient

In all cases, gallotannins (or gallic tannins) should demonstrate an ability to consume the oxygen directly, and more specifically they should be able to consume at least 0.10 ± 0.05 mg of O2 per litre, per day and per gram of tannins (commercial extract).

Figure 3: Pathway to determine oxygen consumption rate

  1.              Antioxidasic ability
    1.        Principle

Determination of gallotannins’ antioxidasic ability to contribute to antioxidasic protection in terms of the laccase activity of compounds in must and wine.

  1.        Products

Ethanol at 96% volume, CAS No. 64-17-5

Tartaric acid: MM = 150.09, CAS No. 87-69-4

Sodium acetate: MM = 82.03, CAS No. 6131-90-4

Syringaldazine (4-hydroxy-3,5-dimethoxybenzaldehyde azine): MM = 360.36, CAS No. 14414-32-5

Polyvinylpolypyrrolidone: PVPP, CAS No. 25249-54-1

Must botrytised with laccase activity

Distilled water (HPLC quality)

  1.        Protocols

2 g/L oenological tannin solution: dissolve 200 mg of oenological tannins in 100 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

Buffer solution (8.2 g/L): dissolve 410 mg of sodium acetate in 50 mL of distilled water.

Syringaldazine solution (0.06 g/L): dissolve 30 mg of syringaldazine in 500 mL of ethanol.

  1.        Tests
  1.                   Add 4 mL of botrytised must to 1 mL of oenological tannin solution in tube, which will correspond to sample modality.
  2.                   Add 4 mL of botrytised must to 1 mL of model wine solution in tube, which will correspond to control modality.
  3.                   After 4 minutes (precisely), add 0.8 g of PVPP in both tube (sample and control modalities), stirred and centrifuged for 10 minutes at 8,500 rpm.
  4.                   Recover 1 mL of the supernatant (for both sample and control modalities), into 1.4 mL of buffer solution and 0.6 mL of syringaldazine solution. Put the mixture into a plastic spectrophotometer cuvette (10 mm path length).
  5.                   Measure the absorbance at 530 nm every minute for 5 minutes (including time measurements at 0 minutes).
  6.                   Then determine the laccase activity and the residual laccase activity by using the following equations and Figure 3:

𝐿𝑎𝑐𝑐𝑎𝑠𝑒 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦 = 46.15 𝑥 Δ𝐴 µ𝑚𝑜𝑙. 𝐿−1. 𝑚𝑖𝑛−1 = 46.15 𝑥 Δ𝐴 𝑈𝐿

% 𝑜𝑓 𝑟𝑒𝑠𝑖𝑑𝑢𝑎𝑙 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦 = (𝑙𝑎𝑐𝑐𝑎𝑠𝑒 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦𝑠𝑎𝑚𝑝𝑙𝑒/ 𝑙𝑎𝑐𝑐𝑎𝑠𝑒 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦𝑐𝑜𝑛𝑡𝑟𝑜𝑙) 𝑥 100

Figure 4: Example determination of .

In all cases, gallotannins (or gallic tannins) should demonstrate an antioxidasic ability, and more specifically they should be able to reduce the residual laccase activity by at least 50%. This value is valuable for must and wine containing less than 5 UL (units of laccases).

  1.              Colour stabilisation
    1.        Principle

Determination of gallotannins colour stabilisation properties to promote the expression, stabilisation and preservation of colour in red must and wine.

  1.        Products

Ethanol at 96% volume, CAS No. 64-17-5

Tartaric acid: MM = 150.09, CAS No. 87-69-4

Malvidin-3-O-glucoside: MM = 528.87, CAS No. 18470-06-9

  1.        Protocols

0.8 g/L oenological tannin solution: dissolve 80 mg of oenological tannins in 100 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

0.1 g/L malvidin-3-O-glucoside solution: dissolve 10 mg of malvidin-3-O-glucoside in 100 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

  1.        Tests
  1.                   Place 0.75 mL of oenological tannin solution and 0.75 mL of model wine solution in one 2-mL stoppered conical tube – hereinafter a “tube” – and keep it in the dark at room temperature. This tube will be called “T0”.
  2.                   Place 0.75 mL of malvidin-3-O-glucoside solution and 0.75 mL of model wine solution in one tube and keep it in the dark at room temperature. This tube will be called “M”.
  3.                   Place 0.75 mL of oenological tannin solution and 0.75 mL of malvidin solution in one tube and keep it in the dark at room temperature. This tube will be called “TM”.
  4.                   After 7 days, measure the absorbance at 450, 520, 570 and 630 nm of the three tubes (TM, T0 and M).
  5.                   Subtract the absorbance values of T0 to TM to obtain the absorbance, avoiding the interferences due to the “natural” colour of the oenological tannin.

A(TM) – A(T0) = A(T)

  1.                   Then, determine the CIELAB coordinates (L*, a* and b*) corresponding to tannin solution with malvidin-3-O-glucoside (T) and malvidin-3-O-glucoside solution (M) with the free MSCV software (https://www.unirioja.es/color/descargas.shtml) or equivalent.

The formulas to be applied for the calculation of the copigmentation index are as follows:

ΔEab.TS: total colour difference between the solution of malvidin-3-O-glucoside containing commercial tannins (T) and a pure white colour solution (W).

ΔEab.CS: total colour difference between the solution of malvidin-3-O-glucoside (M) and a pure white colour solution (W).

The CIELAB coordinates of a pure white colour solution are L* = 100.00, a* = 0.00 and b* = 0.00.

In all cases, gallotannins (or gallic tannins) should demonstrate an ability to stabilise the colour, and more specifically their a copigmentation index should read as higher than 30.0 ± 2.0% after 7 days.

 

 

Note: Alternative methods of determination can be used in place of any of the methods described, on the condition that these have been internally validated.

 

  1.                   Bibliography
  •                  Sarneckis, C.J.; Dambergs, R.G.; Jones, P.; Mercurio, M.; Herderich, M.J.; Smith, P.A. Quantification of condensed tannins by precipitation with methyl cellulose: development and validation of an optimised tool for grape and wine analysis. Australian Journal of Grape Wine Research 2006, 12, 39–49.
  •                  Vignault, A.; González-Centeno, M.R.; Pascual, O.; Gombau, J.; Jourdes, M.; Moine, V.; Iturmendi, N.; Canals, J.M.; Zamora, F.; Teissedre, P.-L. Chemical characterization, antioxidant properties and oxygen consumption rate of 36 commercial oenological tannins in a model wine solution. Food Chemistry 2018, 268, 210–219.
  •                  Vignault, A.; Pascual, O.; Jourdes, M.; Moine, V.; Fermaud, M.; Roudet, J.; Canals, J.M.; Teissedre, P.-L.; Zamora, F. Impact of enological tannins on laccase activity. OENO One 2019, 53, 27–38.
  •                  Vignault, A.; Pascual, O.; Gombau, J.; Jourdes, M.; Moine, V.; Canals, J.M.; Teissedre, P.-L.; Zamora, F. Recent advances of the OIV working group on oenological tannins in the study of the functionalities of oenological. BIO Web of Conferences 2019, 15, 02015.
  •                  Vignault, A.; Gombau, J.; Pascual, O.; Jourdes, M.; Moine, V.; Canals, J.M.; Zamora, F.; Teissedre, P.-L. Copigmentation of Malvidin-3-O-Monoglucoside by Oenological Tannins: Incidence on Wine Model Color in Function of Botanical Origin, pH and Ethanol Content. Molecules 2019, 24, 1–15.
  •                  Vignault, A.; Gombau, J.; Jourdes, M.; Moine, V.; Canals, J.M.; Fermaud, M.; Roudet, J.; Zamora, F.; Teissedre, P.-L. Oenological tannins to prevent Botrytis cinerea damage in grapes and musts: kinetics and electrophoresis characterization of laccase. Food Chemistry 2020, 316, 126334.
  •                  Vignault, A. Tanins œnologiques : caractéristiques, propriétés et fonctionnalités. Impact sur la qualité des vins. Thèse de doctorat, Université de Bordeaux et Universitat Rovira i Virgili, 2019.

 

 

 

Profisetinidins/ Prorobitenidins tannins

OENOLOGICAL TANNINS

Specific monograph for oenological tannins containing
profisetinidins/prorobitenidins

(OIV-OENO 675D-2022)

Profisetinidins/prorobitenidins are a sub-class of condensed (or proanthocyanic) tannins. Tannins from the quebracho and acacia spp. tree are included in this sub-class.

  1.                  Method for the determination of sub-class affiliations
    1.           Characterisation by high-performance liquid chromatography (HPLC)
      1.   Principle

This method is designed to verify the presence of characteristic components of condensed tannins of the profisetinidin/prorobitenidin sub-group and measure their total concentration. It is applicable to preparations of oenological tannins that are declared as pure and thus as not containing tannins with small masses from different families or sub-families (or classes).

  1.   Reagents, material and apparatus
    1.                    Reagents

(+)-catechin, CAS No. 154-23-4

Ultrafiltered water (resistivity: 18.3 MΩ·cm)

Water (HPLC quality)

Methanol (HPLC quality)

Formic acid (HPLC quality)

  1.                    Materials

100-mL borosilicate-glass flask

Filters with 0.45 µm pore size diameter

Plastic 1-mL syringe

  1.                    Apparatus

Technical balance with precision of 0.01 g

Analytical balance with precision of 0.1 mg

Class-A volumetric glassware

Mass chromatographic system with spectrometry detection composed of:

-                      Gradient pump for binary or quaternary mix

-                      Injector fitted with a loop of 10 µL

-                      Spectrophotometric detector at 280 nm fixe wavelength

-                      Column Eclipse Plus C-18 (for example): 2.1 x 100 mm, 1.8 µm particle size

-                      ESI-SIM (Single Ion Monitoring mode via Electro Spray Ionisation) ionisation source

-                      Mass spectrometer detector: quadrupole time of flight (Q-TOF)

  1.   Preparation of samples and standards

Samples: weigh approximately 0.5 g of oenological tannins on the analytical balance and make a note of the weight. Dissolve the oenological tannins in 100 mL of ultrafiltered water in a 100-mL borosilicate-glass flask and mix well.

Preparation of standard solutions: put 10 mg of (+)-catechin in solution into 50 mL of ultrafiltered water, corresponding to a 200 mg/L concentration. Then carry out dilutions in ultrafiltered water to obtain 5, 10, 20, 40, 60, 80 and 100 mg/L concentrations.

Solvent A: water (HPLC quality) containing 0.1% of formic acid.

Solvent B: methanol containing 0.1% of formic acid.

  1.   Procedure

The sample solutions and standard solutions are filtered on 0.45 µm (pore size diameter) filters and analysed by chromatography under the following conditions given by way of example:

Injected volume: 10 µL of sample solution or standard solution of (+)-catechin

 Detection at 280 nm

Composition of elution gradient: (time, % of solvent A)

0min, 99.0%; 0.5 min, 94.0%; 20 min, 50.0%; 25 min, 0.0%; 32 min, 94.0% and 10 min for equilibrium.

Flow rate: 0.3 mL/min

Quantification and detection of the characteristic components of condensed tannins from the profisetinidin/prorobitenidin sub-group or sub-class according to the ESI-SIM scan and Q-ToF detection (for example).

Table 1: Example chemical formulas and m/z of the different profisetinidins/prorobitenidins (for the quebracho tree)

Compound

Chemical formula

m/z

(+)-catechin

C15H14O6

290.1

(-)-epicatechin

C15H14O6

290.1

Catechin-fisetinidol dimers

C30H26O11

562.1

Catechin-fisetinidol trimers

C45H38O16

834.2

Catechin-fisetinidol tetramers

C60H50O21

1106.3

Table 2: Example chemical formulas and m/z of the different profisetinidins/prorobitenidins (for the acacia tree)

Compound

Chemical formula

m/z

(+)-catechin

C15H14O6

290.1

(-)-epicatechin

C15H14O6

290.1

(-)-epicatechin-3-O-gallate

C22H18O10

442.4

Fisetinidol-gallocatechin dimers

C30H26O12

578.1

Robinetinidol-catechin dimers

C30H26O12

578.1

Chalcan-flavan dimers (gambiriin)

C30H28O12

580.1

Catechine-fisetinidol-robinetinidol or gallocatechin-fisetinidol-fisetinidol trimers

C45H58O17

850.2

Robinetinidol-robinetinidol-catechin or gallocatechin-fisetinidol-robinetinidol trimers

C45H38O17

866.2

Figure 1: Example ESI-SIM scan of quebracho tree

 

 

Figure 2: Example ESI-SIM scan of acacia tree

  1.           Conclusion

An oenological tannin is recognised as a profisetinidin/prorobitenidin when:

-                      its total polyphenol content is higher than 65% (gravimetric method in Annex 1 of the general monograph OIV-OENO 624-2022),

-                      its molecular procyanidin/prodelphinidin content as characterised by the HPLC method is higher than 20 mg (for quebracho tannins) and 150 mg (for acacia tannins) equivalent of (+)-catechin per gram of oenological tannins.

  1.                  Methods of measurement of properties and functionalities

 

The following compliance methods and criteria are only applicable when the property/functionality is claimed on the preparation of tannins.

 

  1.           Antioxidant ability
    1.   Principle

Determination of profisetinidins/prorobitenidins’ antioxidant ability to contribute to the protection of must and wine from oxidation.

  1.   Products
    1.                    Antioxidant capacity

DPPH (2,2-diphenyl-1-picrylhydrazyl): MM = 394.32

Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid): MM = 250.29

Methanol at 99.9% volume

96-well microplate reader (FLUOstar Omega - BMG Labtech, for example)

  1.                    Direct oxygen consumption (OCR)

Ethanol at 96% volume, CAS No. 64-17-5

Tartaric acid: MM = 150.09, CAS No. 87-69-4

Iron (III) chloride hexahydrate: MM = 270.30, CAS No. 7705-08-0

Copper (II) sulfate pentahydrate: MM = 249.68, CAS No. 7758-98-7

Clear glass bottles with inserted pills of 0.75-L capacity

NomaSens oximeter, for example

  1.   Protocols
    1.                    Antioxidant capacity (DPPH assay)

0.15 g/L oenological tannin solution: dissolve 37.5 mg of oenological tannins in 500 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5). Dilution of oenological tannins solution could be needed if the measurement absorbance is higher than 1 unit (in this case the dilution should be included in the calculation).

1mM Trolox solution: dissolve 125 mg of Trolox in 500 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

Calibration curve:  dissolve in 1, 0.8, 0.6, 0.4, 0.2 and 0.1 mL of 1 mM Trolox solution into 0, 0.2, 0.4, 0.6, 0.8 and 0.9 mL of model wine solution. These quantities correspond to 1, 0.8, 0.6, 0.4, 0.2 and 0.1 mM final concentration of Trolox respectively.

6.10-5 M DPPH solution: dissolve 2.36 mg of DPPH in 100 mL of methanol. The solution should be freshly prepared.

  1.                    Direct oxygen consumption (OCR)

1 g/L oenological tannin solution: dissolve 0.75 g of oenological tannins in 750 mL of model wine solution.

Model wine solution: dissolve 4 g of tartaric acid, 2.25 mg of Iron (III) chloride hexahydrate and 0.225 mg of Copper (II) sulfate pentahydrate in 90 mL of ethanol and 660 mL of distilled water. The pH should be adjusted at 3.5.

  1.   Tests
    1.                    Antioxidant capacity

First a blank containing solely the DPPH reagent (RB) is measured at 515 nm by placing 190 µL of DPPH solution (1.3.1) in all the wells of the plate. Then, add 10 µL of oenological tannin solution (samples), distilled water (blank) or Trolox curve solution (standards) into the wells and measure (MS) at 515 nm after 30 min.

See Figure 2 for an example of how to fill the plate.

The formula to be applied for the calculation of the antioxidant capacity is as follows:

  1.                 
  2.                 

where “a” and “b” correspond respectively to the slope and the constant of the Trolox calibration curve: Absorbance = f ([Trolox])  Absorbance = ax + b

In all cases, profisetinidins/prorobitenidins should demonstrate an antioxidant capacity, and more specifically they should have more than 450 ± 50 mg equivalent Trolox per gram of tannins (commercial extract).

Figure 3: Example 96-well plate

  1.                    Direct oxygen consumption (OCR)

First the model wine solution is saturated with oxygen at 8 mg/L by bubbling with air for 10 min at 20-25 °C. Then, add the oenological tannins to the model wine solution in the bottles filled to 0.75 L. Seal the bottles hermetically and shake to fully homogenise.

  1.               Measure the oxygen consumed every two days starting 1h after the filled of the bottles.
  2.               To determine the oxygen consumption rate, follow the pathway as shown in Figure 2
    •                   represent the oxygen consumption versus the time,
    •                   then represent the inverse of the oxygen consumed versus the inverse of the time,
    •                   the oxygen consumption rate corresponds to the inverse of the slope coefficient:

OCR t0 mg of O2 consumed per day and per g of tannins = 1/A, A being the slope coefficient

In all cases, profisetinidins/prorobitenidins should demonstrate an ability to consume the oxygen directly, and more specifically they should be able to consume at least 0.10 ± 0.05 mg of O2 per litre, per day and per gram of tannins (commercial extract).

 

Figure 4: Pathway to determine oxygen consumption rate

 

 

  1.           Antioxidasic ability
    1.   Principle

 

Determination of profisetinidins/prorobitenidins’ antioxidasic ability to contribute to antioxidasic protection in terms of the laccase activity of compounds in must and wine.

  1.   Products

Ethanol at 96% volume, CAS No. 64-17-5

Tartaric acid: MM = 150.09, CAS No. 87-69-4

Sodium acetate: MM = 82.03, CAS No. 6131-90-4

Syringaldazine (4-hydroxy-3,5-dimethoxybenzaldehyde azine): MM = 360.36, CAS No. 14414-32-5

Polyvinylpolypyrrolidone: PVPP, CAS No. 25249-54-1

Must botrytised with laccase activity

Distilled water (HPLC quality)

  1.   Protocols

2 g/L oenological tannin solution: dissolve 200 mg of oenological tannins in 100 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

Buffer solution (8.2 g/L): dissolve 410 mg of sodium acetate in 50 mL of distilled water.

Syringaldazine solution (0.06 g/L): dissolve 30 mg of syringaldazine in 500 mL of ethanol.

  1.   Tests
  1.                  Add 4 mL of botrytised must to 1 mL of oenological tannin solution in tube, which will correspond to sample modality.
  2.                  Add 4 mL of botrytised must to 1 mL of model wine solution in tube, which will correspond to control modality.
  3.                  After 4 minutes (precisely), add 0.8 g of PVPP in both tube (sample and control modalities), stirred and centrifuged for 10 minutes at 8,500 rpm.
  4.                  Recover 1 mL of the supernatant (for both sample and control modalities), into 1.4 mL of buffer solution and 0.6 mL of syringaldazine solution. Put the mixture into a plastic spectrophotometer cuvette (10 mm path length).
  5.                  Measure the absorbance at 530 nm every minute for 5 minutes (including time measurements at 0 minutes).
  6.                  Then determine the laccase activity and the residual laccase activity by using the following equations and Figure 3:

𝐿𝑎𝑐𝑐𝑎𝑠𝑒 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦 = 46.15 𝑥 Δ𝐴 µ𝑚𝑜𝑙. 𝐿−1. 𝑚𝑖𝑛−1 = 46.15 𝑥 Δ𝐴 𝑈𝐿

% 𝑜𝑓 𝑟𝑒𝑠𝑖𝑑𝑢𝑎𝑙 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦 = (𝑙𝑎𝑐𝑐𝑎𝑠𝑒 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦𝑠𝑎𝑚𝑝𝑙𝑒/ 𝑙𝑎𝑐𝑐𝑎𝑠𝑒 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦𝑐𝑜𝑛𝑡𝑟𝑜𝑙) 𝑥 100

Figure 5: Example determination of .

In all cases, profisetinidins/prorobitenidins should demonstrate an antioxidasic ability, and more specifically they should be able to reduce the residual laccase activity by at least 40%. This value is valuable for must and wine containing less than 5 UL (units of laccases).

  1.           Colour stabilisation
    1.   Principle

Determination of profisetinidins/prorobitenidins’ colour stabilisation properties to promote the expression, stabilisation and preservation of colour in red must and wine.

  1.   Products

Ethanol at 96% volume, CAS No. 64-17-5

Tartaric acid: MM = 150.09, CAS No.  87-69-4

Malvidin-3-O-glucoside: MM = 528.87, CAS No. 18470-06-9

  1.   Protocols

0.8 g/L oenological tannin solution: dissolve 80 mg of oenological tannins in 100 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

0.1 g/L malvidin-3-O-glucoside solution: dissolve 10 mg of malvidin-3-O-glucoside in 100 mL of model wine solution (distilled water, 12% vol. of ethanol, 4 g/L of tartaric acid and pH adjusted to 3.5).

  1.   Tests
  1.                  Place 0.75 mL of oenological tannin solution and 0.75 mL of model wine solution in one 2-mL stoppered conical tube – hereinafter a “tube” – and keep it in the dark at room temperature. This tube will be called “T0”.
  2.                  Place 0.75 mL of malvidin-3-O-glucoside solution and 0.75 mL of model wine solution in one tube and keep it in the dark at room temperature. This tube will be called “M”.
  3.                  Place 0.75 mL of oenological tannin solution and 0.75 mL of malvidin solution in one tube and keep it in the dark at room temperature. This tube will be called “TM”.
  4.                  After 7 days, measure the absorbance at 450, 520, 570 and 630 nm of the three tubes (TM, T0 and M).
  5.                  Subtract the absorbance values of T0 to TM to obtain the absorbance avoiding the interferences due to the “natural” colour of the oenological tannin.

A(TM) – A(T0) = A(T)

  1.                  Then, determine the CIELAB coordinates (L*, a* and b*) corresponding to tannin solution with malvidin-3-O-glucoside (T) and malvidin-3-O-glucoside solution (M) with the free MSCV software (https://www.unirioja.es/color/descargas.shtml) or equivalent.

The formulas to be applied for the calculation of the copigmentation index are as follows:

ΔEab.TS: total colour difference between the solution of malvidin-3-O-glucoside containing commercial tannins (T) and a pure white colour solution (W).

ΔEab.CS: total colour difference between the solution of malvidin-3-O-glucoside (M) and a pure white colour solution (W).

The CIELAB coordinates of a pure white colour solution are L* = 100.00, a* = 0.00 and b* = 0.00.

In all cases, profisetinidins/prorobitenidins should demonstrate an ability to stabilise the colour, and more specifically their copigmentation index should read as higher than 3.0 ± 0.5% after 7 days.

 

Note: Alternative methods of determination can be used in place of any of the methods described, on the condition that these have been internally validated.

 

  1.                  Bibliography
  •                   Sarneckis, C.J.; Dambergs, R.G.; Jones, P.; Mercurio, M.; Herderich, M.J.; Smith, P.A. Quantification of condensed tannins by precipitation with methyl cellulose: development and validation of an optimised tool for grape and wine analysis. Australian Journal of Grape Wine Research 2006, 12, 39–49.
  •                   Vignault, A.; González-Centeno, M.R.; Pascual, O.; Gombau, J.; Jourdes, M.; Moine, V.; Iturmendi, N.; Canals, J.M.; Zamora, F.; Teissedre, P.-L. Chemical characterization, antioxidant properties and oxygen consumption rate of 36 commercial oenological tannins in a model wine solution. Food Chemistry 2018, 268, 210–219.
  •                   Vignault, A.; Pascual, O.; Jourdes, M.; Moine, V.; Fermaud, M.; Roudet, J.; Canals, J.M.; Teissedre, P.-L.; Zamora, F. Impact of enological tannins on laccase activity. OENO One 2019, 53, 27–38.
  •                   Vignault, A.; Pascual, O.; Gombau, J.; Jourdes, M.; Moine, V.; Canals, J.M.; Teissedre, P.-L.; Zamora, F. Recent advances of the OIV working group on oenological tannins in the study of the functionalities of oenological. BIO Web of Conferences 2019, 15, 02015.
  •                   Vignault, A.; Gombau, J.; Pascual, O.; Jourdes, M.; Moine, V.; Canals, J.M.; Zamora, F.; Teissedre, P.-L. Copigmentation of Malvidin-3-O-Monoglucoside by Oenological Tannins: Incidence on Wine Model Color in Function of Botanical Origin, pH and Ethanol Content. Molecules 2019, 24, 1–15.
  •                   Vignault, A.; Gombau, J.; Jourdes, M.; Moine, V.; Canals, J.M.; Fermaud, M.; Roudet, J.; Zamora, F.; Teissedre, P.-L. Oenological tannins to prevent Botrytis cinerea damage in grapes and musts: kinetics and electrophoresis characterization of laccase. Food Chemistry 2020, 316, 126334.
  •                   Vignault, A. Tanins œnologiques : caractéristiques, propriétés et fonctionnalités. Impact sur la qualité des vins. Thèse de doctorat, Université de Bordeaux et Universitat Rovira i Virgili, 2019.

 

Thiamine hydrochloride

COEI-1-THIAMIN Thiamine hydrochloride

3-[(4-amino-2-methyl-5-pyrimidinyl)methyl-5-

(2-hydroxyethyl-4-methylthiazolium hydrochloride

Thiamini hydrochloridum

= 337.

  1. Objective, origin and scope of application

This product is used to promote alcohol fermentation. Its use is subject to statutory restrictions placed on limiting thiamine content.

  1. Labelling

The label should indicate the purity percentage of the product, the use-by date, and the safety and storage requirements.

  1. Properties

White or substantially white crystalline powder or colorless crystals with a slight characteristic odor.  Easily soluble in water, soluble in glycerol, minimally soluble in alcohol, virtually insoluble in chloroform and ethyl ether.

 

  1. Solubility

Water at 20 °C

1000 g/l

Alcohol, 95% by vol.

12.5 g/l

Glycerol

63.3 g/l

Ethyl ether

insoluble

  1. Proof

Proof test 5.1 may be omitted when tests 5.2 and 5.3 are performed. Proof test 5.2 may be omitted when tests 5.1 and 5.3 are performed (methods described in the Annex).

5.1.    Examine the thiamine hydrochloride by absorption spectrophotometry in infrared light.

The maximum absorption values of the spectrum obtained from the substance tested correspond, in position and relative intensity, to those obtained from thiamine hydrochloride SCR.  If the spectra exhibit differences, dissolve the substance to be tested and the chemical reference substance, respectively, in water.  Evaporate the solutions until dry and produce new spectra from the resulting residues.

5.2.    Dissolve about 20 mg thiamine hydrochloride in 10 ml of water. Add 1 ml dilute

acetic acid (R) and 1.6 ml of 1M sodium hydroxide (R). Heat in a 100 °C water bath for 30 minutes and let cool.  Add 5 ml of dilute sodium hydroxide solution (R), 10 ml potassium hexacyanoferrate (III) solution (R) and 10 ml of butanol.  Shake vigorously for 2 minutes. An intense light blue fluorescence will spread in the alcoholic layer, especially ultraviolet light at 365 nm. Repeat the test using 0.9 ml 1M sodium hydroxide and 0.2 g sodium sulfite replacing the 1.6 ml 1M sodium hydroxide. Virtually no fluorescence will be observed.

5.3.    Thiamine hydrochloride produces chloride reactions (method described in the Annex).

5.4.    Thiamine hydrochloride contains at least 98.5 pp 100, and at most the equivalent of 101.5 pp 100, 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-5-(2-hydroxyethyl)-4-methylthiazo-lium hydrochloride, as calculated with respect to the anhydrous substance.

  1. Tests

6.1.    Desiccation Loss

Place 2 g of thiamine in an oven at 105 °C for 3 hours. Weight loss should not be greater than 5 pp 100.

6.2.    Sulfur Ash

Using the method described in the annex, analye 2 g thiamine hydrochloride. The sulfur ash content should not be greater than 0.1 pp 100.

6.3.    Preparing the Solution for Tests

Dissolve 5 g thiamine hydrochloride in water and fill to 100 ml.

6.4.    Determining pH

The pH of the solution prepared for tests under Paragraph 5.3 and diluted by one-half should have a pH of between 2.7 and 3.3.

6.5.    Nitrates

Add 1 ml water and 1 ml concentrated sulfuric acid (R) to 1 ml of the solution prepared for tests under Paragraph 5.3.  Cool. Deposit 2 ml of the extemporaneously prepared 5 pp 100 iron (II) sulfate solution on the surface of the liquid. No brown ring should form at the interface of the 2 layers.

6.6.    Heavy Metals

Test for heavy metals in 10 ml of the solution prepared for tests under Paragraph 5.3 using the method described in the Annex.  (Heavy metal content expressed in terms of lead should be less than 10 mg/kg).

6.7.    Lead

Using the method indicated in the annex, determine lead content in the test solution (5.3). (Lead content should be less than 5 mg/kg).

6.8.    Mercury

Using the method indicated in the Annex, determine the mercury content in the test solution (5.3). (Mercury content should be less than 1 mg/kg).

6.9.    Arsenic

Using the method indicated in the Annex, determine the arsenic content in the test splution (5.3). (Arsenic content should be less than 3 mg/kg).

  1. Quantitative Analysis

Dissolve 0.150 g of thiamine hydrochloride in 5 ml anhydrous formic acid. Add 65 ml anhydrous acetic acid, then, while stirring, 10 ml mercuric acetate solution. Quantitatively analyze organic base halogenated salts in a non-aqueous medium by titrating with 0.1M perchloric acid. Determine the point of equivalence by potentiometric analysis. 1 ml of 0.1M perchloric acid corresponds to 16.86 mg of C12H18Cl2N4OS.

  1. Storage

Thiamine hydrochloride should be stored in properly sealed, non-metal containers kept away from light.

Zeolite Y-faujasite

COEI-1-ZEOLIT Zeolite Y-Faujasite

  1. Object, origin and field of application

Zeolite Y-Faujasite is synthesized from alumina sources such as sodium aluminate and silica sources such as sodium silicate.

Zeolite Y-Faujasite incorporated in depth filtration filter sheets play an important role in simultaneously clarifying and selectively removing taint molecules which alter wine flavours

  1. Characteristics

 

Zeolite Y-Faujasite for selectively removing taint molecules, such as tricholoanisole, are characterized by having a silica-to-alumina ratio of 3 or higher. The negative charges of the framework are balanced by the positive charges of cations in non-framework positions.

  1. Test trials

 

3.1.    Loss on drying

Put 5g of Zeolite Y-Faujasite in a capsule. Heat in an oven to 120 2°C. After two hours, the mass loss should be smaller than 5%.

3.2.    Odour and taste

Put 2.5 g of Zeolite Y-Faujasite in 1 L of wine. Leave standing for 24h. Compare the taste (for example with the duo-trio test or refer to the sensorial analysis document of the OIV) of the test wine to wine not containing any zeolite.

The test can also be carried out using filter sheets with Zeolite Y-Faujasite preconditioned according to the manufacturer usage instructions. Compare the taste of the filtered wine to wine filtered through standard depth filtration sheets not containing any specific zeolite.

The Zeolite Y-Faujasite should not impart any foreign odour or taste to the wine.

3.3.    pH

Mix 1g of specific Zeolite Y-Faujasite in 40 mL of deionized water and shake for 20 minutes. After 5 minutes of rest, the pH of the supernatant is between 5 and 7.

3.4.    Metal contents

3.4.1.  Test solution preparation

Slowly add tartaric acid to 1 litre of deionized water until a pH of 3 is reached. Into a 500 ml flask with a large neck which can be hermetically sealed, add 500 ml of the tartaric acid solution. Weigh 10g of dried specific Zeolite Y-Faujasiteand sprinkle the sample in the constantly stirred solution. After this addition, shake vigorously for 5 minutes. Allow to stand for 24 to 48 hours. Decant, centrifuge, or filter if necessary to obtain at least 200 ml of clear liquid.

3.4.2.  Arsenic

In the test solution obtained following the procedure in 3.4.1, determine Arsenic using an atomic absorption spectrometer, according to the method described in chapter II of the International Oenological Codex. Arsenic content must be less than 0.3 mg/kg specific Zeolite Y-Faujasite.

3.4.3.  Cadmium

In the test solution obtained following the procedure in 3.4.1, determine Cadmium using an atomic absorption spectrometer, according to the method described in chapter II of the International Oenological Codex. Cadmium content must be less than 0.3 mg/kg specific Zeolite Y-Faujasite.

3.4.4.  Chromium

In the test solution obtained following the procedure in 3.4.1, determine Chromium using an atomic absorption spectrometer according to the method described in Chapter II of the International Oenological Codex. Chromium content must be less than 0.3 mg/kg specific Zeolite Y-Faujasite.

3.4.5.  Copper

In the test solution obtained following the procedure in 3.4.1, determine Copper using an atomic absorption spectrometer, according to the method described in chapter II of the International Oenological Codex. Copper content must be less than 0.3 mg/kg specific Zeolite Y-Faujasite.

3.4.6.  Iron

In the test solution obtained following the procedure in 3.4.1, determine Iron using an atomic absorption spectrometer, according to the method described in chapter II of the International Oenological Codex. Iron

content must be less than 3 mg/kg specific Zeolite Y-Faujasite.

3.4.7.  Lead

In the test solution obtained following the procedure in 3.4.1, determine Lead using an atomic absorption spectrometer, according to the method described in chapter II of the International Oenological Codex. Lead content must be less than 0.3 mg/kg specific Zeolite Y-Faujasite.

3.4.8.  Manganese

In the test solution obtained following the procedure in 3.4.1, determine Manganese using an atomic absorption spectrometer. Manganese content must be less than 0.3 mg/kg specific Zeolite Y-Faujasite.

3.4.9.  Mercury

In the test solution obtained following the procedure in 3.4.1, determine Mercury using an atomic absorption spectrometer, according to the method described in chapter II of the International Oenological Codex. Mercury content must be less than 0.1 mg/kg specific Zeolite Y-Faujasite.

3.4.10.     Selenium

In the test solution obtained following the procedure in 3.4.1, determine Selenium using an atomic absorption spectrometer. Selenium content must be less than 1 mg/kg specific Zeolite Y-Faujasite.

3.4.11.     Silver

In the test solution obtained following the procedure in 3.4.1, determine Silver using an atomic absorption spectrometer, according to the method described in chapter II of the International Oenological Codex. Silver content must be less than 0.3 mg/kg specific Zeolite Y-Faujasite.

3.4.12.     Zinc

In the test solution obtained following the procedure in 3.4.1, determine Zinc using an atomic absorption spectrometer, according to the method described in chapter II of the International Oenological Codex. Zinc content must be less than 0.3 mg/kg specific Zeolite Y-Faujasite.

  1. Identification

 

4.1.    Efficacy testing

Efficacy testing of depth filtration pads containing Zeolite Y-Faujasite for the selective removal of 2,4,6 trichloroanisole (TCA) involves treating wine contaminated with 20 ng/L of 2,4,6 trichloroanisole (TCA). The pad is set in an appropriate filtration device and preconditioned by rinsing with clean water. After preconditioning, the contaminated wine is pushed through the filter pad at a rate of 15 litres, per meter squared of filtration area, per minute. Samples of the filtered wine are taken every 235 litres per meters squared of filtration area. Each filtered wine sample is analysed using the GCMS. The TCA concentration data from each sampling event is then integrated to create a filter pad breakthrough curve.

 

 

The breakthrough curve shown was generated using a number of commercial pads produced on various production dates.

  1. Storage conditions

Selective filter sheets incorporating Zeolite Y-Faujasiteshould must be stored in their original packaging in an odourless, dry and ventilated environment

Appendix 1

  • Patent reference: WO 2007/061602 A1
  • Highly selective molecular confinement for the prevention and removal of taint in foods and beverages John Cunningham.