Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
  • C08B37/00—Preparation of polysaccharides not provided for in groups C08B1/00 - C08B35/00; Derivatives thereof
  • C08B37/0006—Homoglycans, i.e. polysaccharides having a main chain consisting of one single sugar, e.g. colominic acid
  • C08B37/0024—Homoglycans, i.e. polysaccharides having a main chain consisting of one single sugar, e.g. colominic acid beta-D-Glucans; (beta-1,3)-D-Glucans, e.g. paramylon, coriolan, sclerotan, pachyman, callose, scleroglucan, schizophyllan, laminaran, lentinan or curdlan; (beta-1,6)-D-Glucans, e.g. pustulan; (beta-1,4)-D-Glucans; (beta-1,3)(beta-1,4)-D-Glucans, e.g. lichenan; Derivatives thereof
  • C08B37/0027—2-Acetamido-2-deoxy-beta-glucans; Derivatives thereof
  • C08B37/003—Chitin, i.e. 2-acetamido-2-deoxy-(beta-1,4)-D-glucan or N-acetyl-beta-1,4-D-glucosamine; Chitosan, i.e. deacetylated product of chitin or (beta-1,4)-D-glucosamine; Derivatives thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L5/00—Compositions of polysaccharides or of their derivatives not provided for in groups C08L1/00 or C08L3/00
  • C08L5/08—Chitin; Chondroitin sulfate; Hyaluronic acid; Derivatives thereof
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12H—PASTEURISATION, STERILISATION, PRESERVATION, PURIFICATION, CLARIFICATION OR AGEING OF ALCOHOLIC BEVERAGES; METHODS FOR ALTERING THE ALCOHOL CONTENT OF FERMENTED SOLUTIONS OR ALCOHOLIC BEVERAGES
  • C12H1/00—Pasteurisation, sterilisation, preservation, purification, clarification, or ageing of alcoholic beverages
  • C12H1/02—Pasteurisation, sterilisation, preservation, purification, clarification, or ageing of alcoholic beverages combined with removal of precipitate or added materials, e.g. adsorption material
  • C12H1/04—Pasteurisation, sterilisation, preservation, purification, clarification, or ageing of alcoholic beverages combined with removal of precipitate or added materials, e.g. adsorption material with the aid of ion-exchange material or inert clarification material, e.g. adsorption material
  • C12H1/0416—Pasteurisation, sterilisation, preservation, purification, clarification, or ageing of alcoholic beverages combined with removal of precipitate or added materials, e.g. adsorption material with the aid of ion-exchange material or inert clarification material, e.g. adsorption material with the aid of organic added material
  • C12H1/0424—Pasteurisation, sterilisation, preservation, purification, clarification, or ageing of alcoholic beverages combined with removal of precipitate or added materials, e.g. adsorption material with the aid of ion-exchange material or inert clarification material, e.g. adsorption material with the aid of organic added material with the aid of a polymer

Definitions

• the present invention relates to a polymer based on chitosan and/or a derivative thereof, phytic acid or a salt thereof and optionally polyaspartate, and the use thereof to treat fermented beverages, in particular wine, in order to prevent phenomena of oxidation and/or precipitation of calcium tartrate crystals.
• Grapes is derived by pressing grapes to extract the must, which is fermented by yeast that transforms the natural grape sugars into alcohol. Fermentation can take place in contact with the grape skins, from which larger amounts of polyphenols (responsible for the wine’s colour), aromas, metals and other components are thus extracted.
• the wine thus obtained is kept for a period varying from a few weeks to several years, according to type, until it is ready for packaging and market distribution. Before being consumed, wine can be stored for many more months or years at the point of sale or in the buyer’s cellar.
• Iron thus triggers a redox cascade reaction which modifies the colour and produces aldehydes: in the initial phase, oxidation leads to the loss of the primary aromas characteristic of the grape variety or region, and in the more advanced phases causes the colour to turn brown and gives rise to smells of honey, cut apple and potato peel, which completely denature the wine until making it undrinkable. This process of deterioration is more evident in white and rose wines than in reds.
• One strategy is to reduce the presence, in wine, of polyphenols, which trigger a cascade oxidation reaction: this is done preventively by avoiding maceration with the skins and reducing the pressing of marc; the removal of polyphenols, by contrast, is carried out with carbon, casein or other proteins allowed by regulations.
• ferrocyanide treatment As for the reduction of iron, the authorised practice that gives significant results is ferrocyanide treatment, by now abandoned due to the toxicological risks tied to the use of potassium ferrocyanide.
• a partial deferrization effect can also be obtained with a chitosan-based treatment of microbial origin, or calcium phytate salts or polyvinyl imidazole-polyvinylpyrrolidone PVI-PVP resin (oenological practices admitted under Reg. EU 934/2019)
• the additive approach envisages the addition of reducing substances that, upon reacting with radicals, block the chain of reactions: for this purpose, use is essentially made of sulphur dioxide, sometimes in combination with ascorbic acid.
• the adjuvant calcium phytate despite being allowed under current legislation, has also fallen totally into disuse because the qualitative damage caused by the treatment has shown to be greater than the benefit obtained with deferrization.
• calcium phytate is capable of removing iron only in ferric and not ferrous form, at high treatment temperatures: in practice, it is thus necessary to heat and oxygenate the wine in order to be able to eliminate a significant portion of iron, thereby causing, however, a considerable qualitative deterioration of the wine.
• the synthetic polymer PVI-PVP has recently been authorised by legislators among oenological practices, but it poses various problems related to application. First of all, it is a very fine powder, difficult to handle, which can cause irritation in the respiratory tract of operators; it cannot be used in the early phases of vinification, must be removed from the wine after a few hours and, finally, it has a very substantial cost for winegrowing enterprises. It should be considered that treatments with ferrocyanide, phytate and PVI- PVP are not allowed under the regulations for organic and biodynamic wines, which represent an important and growing share of wine production.
• chitosan Treatment with chitosan is a practice that may be implemented in modern vinification to reduce iron in a solution; however, even at very high doses (up to 200 g/hl) , the iron present in the wine can be reduced by 50% at most. In consideration of the high cost of the product, chitosan alone thus offers an only partial solution to the problem of the catalysing effect of iron in the oxidation of the wine.
• Calcium is a metal naturally present in wine at concentrations that may exceed 100 mg/l, an increasingly frequent situation as a consequence of climate change. If present above the solubility equilibrium of wine, calcium tartrate forms crystals which bring about a deposit in the bottle that consumers find unpleasant. Unlike potassium tartrate, calcium tartrate has a very slow, non-temperature-dependent crystal formation process; therefore, many classic stabilisation practices applied to wine (cold stabilisation, addition of polyaspartate at the authorised doses, etc.) are not able to prevent the phenomenon. Removing a part of the calcium present from wine, the tartaric acid content being equal, lowers the concentration of calcium tartrate below the solubility thereof and thus prevents its crystallisation.
• the present invention provides an effective solution for overcoming both the problem of the oxidation caused by iron and the problem of crystal formation caused by the excessive presence of calcium in fermented beverages, in particular in alcoholic fermented beverages and preferably in wine.
• the present invention relates to a polymer based on chitosan and phytic acid, or salts thereof, or a polymer based on chitosan, phytic acid or salts thereof and polyaspartate.
• the invention also relates to the use of a polymer based on chitosan and phytic acid, or salts thereof, and/or a polymer based on chitosan, phytic acid or salts thereof and polyaspartate to remove the iron and/or calcium ion from fermented beverages, preferably alcoholic fermented beverages, in particular wine, preferably white, red or rose wine.
• the polymer based on chitosan and phytic acid or salts thereof is obtained by cross-linking between chitosan and phytic acid or salts thereof.
• the polymer based on chitosan, phytic acid or salts thereof and polyaspartate is obtained by cross-linking between phytic acid or salts thereof and chitosan, during which polyaspartate is added.
• the polymer based on chitosan and phytic acid or salts thereof has demonstrated to be particularly effective in selectively removing the iron ion from a fermented beverage, preferably an alcoholic fermented beverage, more preferably wine. Therefore, this polymer is used to prevent and mitigate the oxidation phenomena caused by the iron ion.
• the polymer based on chitosan, phytic acid or salts thereof, and polyaspartate has demonstrated to be particularly effective in simultaneously removing the iron ion and calcium ion from a fermented beverage, preferably an alcoholic fermented beverage, more preferably from wine, while showing good levels of selectivity for such ions. Therefore, said polymer is used to prevent and mitigate the oxidation phenomena caused by the iron ion and/or the formation of calcium tartrate crystals that deposit on the bottom of the container containing the beverage.
• the invention also relates to a method for removing the iron and/or calcium ion from fermented beverages, preferably alcoholic ones, in particular wine, which comprises a step in which the beverage is placed in contact with a polymer based on chitosan and phytic acid or salts thereof and/or a polymer based on chitosan, phytic acid or salts thereof, and polyaspartate.
• the polymer is maintained in contact with the beverage for a time comprised between 1 day and 10 days, preferably between 2 days and 7 days.
• the beverage is subsequently filtered, centrifuged or decanted to eliminate the polymer suspension.
• Fig. 1 shows the results of the removal of the iron ion from a white wine using different polymers for comparison: chitosan-sodium phytate polymer (CS-NP); chitosan-phytic acid polymer (CS-AP); chitosan-potassium phytate polymer of (CS-KP); chitosan-polyaspartate polymer (CS-KPA); chitosan-phytate-polyaspartate polymer (CS-AP-KPA).
• CS-NP chitosan-sodium phytate polymer
• CS-AP chitosan-potassium phytate polymer of (CS-KP)
• CS-KPA chitosan-polyaspartate polymer
• CS-AP-KPA chitosan-phytate-polyaspartate polymer
• Fig. 2 shows the effect of the time of contact between a chitosan-phytate polymer and a white wine.
• Fig. 3A shows the selectivity of the CS-AP polymer of the invention for iron versus other ions in white wine.
• Fig. 3B shows a reduction in oxidation phenomena due to the removal of iron in white wine.
• Fig. 3C shows the effects of treatment of the CS-AP polymer on the tonality of a white wine.
• Fig. 4A shows the results of the removal of iron in red wine by the CS-AP polymer.
• Fig. 4B shows the effect on oxidation of the removal of iron in red wine.
• Fig. 4C shows the effect of the CS-AP polymer on the phenolic profile of a red wine.
• Fig. 4D shows the effect on colour of a red wine treated with the CS-AP polymer.
• chitosan means chitosan or a derivative thereof, such as, for example, carboxymethyl chitosan.
• the present invention relates to a polymer obtained from the cross-linking reaction between chitosan of formula (I) and/or a derivative thereof, for example carboxymethyl chitosan:
• Formula (II) or a salt thereof preferably a salt of an alkali or alkaline earth metal, for example sodium, potassium, calcium or magnesium phytate or combinations thereof, and optionally polyaspartate, more preferably polyaspartate of an alkali or alkaline earth metal, for example potassium polyaspartate having the formula (III):
• the phosphate groups of phytic acid or a salt thereof bind, by ionic bonding, to the ammonium groups of chitosan, thus forming a stable cross-linked structure that gels.
• the reaction is made to take place in such a way as to ensure that a part of the phosphate groups of phytic acid or a salt thereof does not bind to chitosan, thus remaining free to chelate iron and/or calcium, for which it has a strong affinity.
• polyaspartate If polyaspartate is present, it reacts with chitosan, since, like phytic acid, it has a strong negative surface charge, thus giving rise to the formation of a cross-linked polymer based on chitosan, phytic acid or salts thereof and aspartate.
• two or three aqueous solutions are prepared depending on whether one wishes to obtain a polymer based on chitosan and phytic acid, or a polymer based on chitosan, phytic acid and polyaspartate: a solution containing chitosan, preferably an acidic solution, a solution containing phytic acid or a salt thereof and a solution containing polyaspartate.
• the aqueous solution of phytic acid or salts thereof is obtained by solubilising, in demineralised water, the phytic acid or the sodium, potassium, calcium or magnesium salts thereof, also in a mixture between the latter.
• the aqueous solution in which the chitosan is dissolved is acidified with an organic acid selected from: acetic, lactic, tartaric, malic, citric and ascorbic acid and combinations thereof. These acids are compatible with use in food and are normally present, for example, in wine.
• the solution of chitosan is added, preferably slowly, to the solution of phytic acid or salts thereof, under stirring, preferably in the presence of a pore-forming agent, for example KCI or NaCI.
• a pore-forming agent for example KCI or NaCI.
• the reaction is allowed to continue at room temperature for a time of between 1 hour and 72 hours, preferably between 4 and 24 hours, with the formation of a white precipitate, the polymer, which is subsequently recovered.
• the phosphate groups of phytic acid bind by ionic bonding to the ammonium groups of chitosan, thus forming a stable cross-linked structure that gels.
• the reaction is made to take place in such a way as to ensure that a part of the phosphate groups of phytic acid does not bind to chitosan, thus remaining free to chelate iron, for which it has a strong affinity.
• the polymer is then dried and crushed to obtain a fine powder.
• the polyaspartate solution is added to the solution of phytic acid or salts thereof with a weight ratio between polyaspartate and phytic acid (or salts thereof) equal to 0.1 -10:1.
• the addition is preferably made in the presence of a pore-forming agent, for example KCI or NaCI.
• a chitosan solution is preferably added, drop by drop, to the solution thus obtained.
• the weight ratio between chitosan and phytic acid or salts thereof is between 0.1 and 20, preferably between 0.1 and 10.
• the solution is kept under stirring until a gel forms, preferably for a time of between 30 minutes and 72 hours, more preferably between 1 and 24 hours. At the end of the reaction the gel that forms is recovered and washed if necessary. Subsequently, the gel is preferably dried and crushed to obtain a powder.
• the polymer based on chitosan and phytic acid or salts thereof and the polymer based on chitosan, phytic acid or salts thereof and polyaspartate are used on their own or in combination, preferably in powder form, to remove the iron and/or calcium ion in fermented beverages, preferably alcoholic fermented beverages, more preferably red, white or rose wine.
• the polymer based on chitosan and phytic acid or salts thereof and the polymer based on chitosan, phytic acid or salts thereof and polyaspartate are used on their own or in combination to prevent the oxidation of fermented beverages caused by iron ions and act through the chelation of these ions and consequent removal thereof by entrapment in the structure of the polymer.
• the fermented beverages keep for longer times, as the nearly total elimination of iron ions prevents oxidative phenomena that result in the deterioration of the organoleptic properties of the fermented beverage, in particular an alcoholic fermented beverage, preferably wine.
• calcium ions present naturally in the fermented beverage are also removed; in particular, the excess calcium ions which can cause the formation of a calcium tartrate precipitate are removed.
• the efficiency of removal in the case of calcium ions is equivalent to at least half the concentration of ions present in the beverage; preferably, more than half the ions present in the beverage are removed with the polymers of the invention, in particular with the polymer based on chitosan, phytic acid or salts thereof and polyaspartate, which has shown to be particularly effective in removing the calcium ion.
• Another polymer that has shown to be particularly effective is the polymer obtained from the reaction of carboxymethyl chitosan and phytic acid or salts thereof.
• the typical concentrations of the calcium ion in fermented beverages, in particular in wine, can exceed 100 mg/L
• the polymers of the invention are thus used to prevent the formation of unaesthetic precipitates of calcium tartrate crystals.
• the method for removing iron and/or calcium ions comprises a step in which the polymers, on their own or in combination, preferably in dry powder form, are dispersed in the fermented beverage, preferably in the alcoholic fermented beverage, for example white, red or rose wine.
• each polymer is used in an amount of between 0.1 and 5 g/l, preferably between 0.1 and 3 g/l, more preferably between 0.1 and 1 .0 g/i.
• Each polymer is suspended directly in the fermented beverage or is first suspended in a volume of water or the beverage to be treated equal to or greater than 10 times the weight of the polymer.
• the beverage containing the polymer is optionally subjected to homogenisation, for example by stirring of the treated mass or recirculation by means of a pump (pumping over in closed tank).
• the polymers are left in a suspension for a time of between 1 and 120 days, preferably between 3 and 60 days, more preferably between 5 and 10 days.
• a time of between 1 and 120 days preferably between 3 and 60 days, more preferably between 5 and 10 days.
• the polymers are left to settle on the bottom of the tank and removed from the system by separation from the beverage, for example by decanting.
• centrifugation or filtration can be performed to separate the polymers loaded with iron and/or calcium from the beverage.
• Example no. 1 Effectiveness of chitosan-phytate polymer in removing iron from wine (Fig. 1).
• a white wine with 3.7 mg/l of total iron is treated with 600 mg/l of chitosan of microbial origin, which is compared with a series of polymers used at the same doses: - CS-NP: chitosan-phytate polymer obtained by cross-linking the above-mentioned chitosan of microbial origin in a sodium phytate solution
• chitosan-phytate polymer obtained by cross-linking the above-mentioned chitosan of microbial origin in a phytic acid solution
• chitosan-phytate polymer obtained by cross-linking the above-mentioned chitosan of microbial origin in a potassium phytate solution
• chitosan-polyaspartate polymer obtained by cross-linking the above-mentioned chitosan of microbial origin in a potassium polyaspartate solution
• chitosan-phytate-polyaspartate polymer obtained by cross-linking the above-mentioned chitosan of microbial origin in a phytic acid and potassium polyaspartate solution.
• a white wine with an original iron content of 1 .6 mg/l was subjected to a treatment of varying duration with 10 g/hl of chitosan-phytate polymer. Over 50% of the iron was absorbed by the polymer in the first 48 hours of contact; however, total removal of the metal was achieved by the 5th-6th day of treatment.
• Example no. 3 Effect of treatment with chitosan-phytate polymer on the quality of white wine
• a white wine with a high iron content was treated with 600 mg/l of chitosan in comparison with the chitosan-phytate polymer. After two days of treatment, the wine was kept in the presence of air to accelerate the oxidation phenomena, and then subjected to chemical analyses.
• the CS-AP polymer confirms a much higher iron absorption capacity than the chitosan of which it is composed, whereas it shows no effect of reducing copper, calcium or phosphorous, thus demonstrating the selectivity of its action (Fig. 3A).
• the CIELab coordinates describe the colour tone of the treated wine as less red and greener than the wine as is and wine treated with chitosan alone (Fig. 3C).
• Example no. 4 Effect of treatment with chitosan-phytate polymer on the quality of red wine
• a red wine with a high iron content was treated with 600 mg/l of chitosan in comparison with the chitosan-phytate polymer. After two days of treatment, the wine was kept in the presence of air to accelerate the oxidation phenomena, and then subjected to chemical analyses.
• the treatment with CS-AP polymer removes the iron almost completely in only two days, without significantly altering the mineral composition of the wine (Fig. 4A).
• the CS-AP polymer does not significantly modify the phenolic profile of the red wine; it absorbs neither anthocyanins nor tannins (Fig. 4C). Although the phenolic composition is unchanged compared to untreated wine, the colour indices describe the wine that remained in contact with the CS-AP polymer as redder, more luminous and with greater chromaticity (Fig. 4D).
• Example no. 5 Effectiveness of chitosan-phytate-polyaspartate polymer in removing iron and calcium from wine
• a white wine with a high calcium content, susceptible to calcium tartrate instability, is subjected to treatment with 60 g/hl of the following adjuvants for comparison: a) chitosan of microbial origin, previously dissolved in 10 times its weight of an aqueous solution acidified with lactic, citric and ascorbic acid; b) chitosan-phytate polymer, suspended in 10 times its weight of water prior to its addition; c) chitosan-phytate-polyaspartate polymer added in the same manner. The polymers were synthesised using the same chitosan as in test sample a).

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• 2022
  • 2022-03-02 IT IT102022000003860A patent/IT202200003860A1/it unknown
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