BEVERAGES

DESCRIPTION

FIELD OF THE INVENTION

This invention relates to a process for the treatment of vegetable based beverages, including, in particular, wine and vinegar .

PRIOR ART

As it is known, alcoholic beverages are generally produced through a step defined, in broad sense, fermentation of a fruit juice. For example, wine is produced from a grape juice which is fermented in the presence (natural or after addition) of yeasts, such as Saccharomyces Cerevisiae. In some cases, the fermented product undergoes a distillation stage, removing from the final product heads and tails, in order to avoid the presence of methanol, which is toxic. This is how grappa and liqueurs are produced.

Fruit juices contains water, sugars, esters and vitamins which are generally beneficial to the health and of pleasing taste; they can also contain substances which are harmful to human health or that can compromise the organoleptic properties both of the juice as such and of the fermented beverage obtained.

If, for example, the grape has undergone attacks by pathogen agents, the wine produced from it may contain ochratoxin A (from bacteria Aspergillum and Penicillum) , 1- octen-3-ol, l-octen-3-one, 2-methylisoborneol , furfural, benzaldehyde, phenylacetaldehyde (from Botyric cinerea) , geosmin (from Penicillium expansum) . Even at very low concentrations (ng/1) , these substances can give the wine an unusual smell of mold, soil, or mushrooms, so impairing the quality.

Another class of materials derived from grapes and giving unpleasant odours to the wine is represented by methoxypyrazines and aldehydes, that are responsible for the negative taste of vegetable and herbaceous in the wine. These substances are present mostly in wines made from grapes not fully matured and/or that have suffered excessive mechanical stress in the preparation of the must.

During the fermentation also other substances with negative olfactory characteristics can be produced, such as volatile ethyl- and vinyl-phenols, which give an animal and a "chemical" smell and derive from contaminated yeasts of the genus Brettanomyces ; sulphur compounds such as sulphides, mercaptans and thiols, which give unpleasant odours, such as burning rubber, cauliflower, onion, garlic, and deriving from the metabolism of the yeast during fermentation; metabolites of some lactic acid bacteria, such as pyrrolidines and pyridines, which give odours smelling like mouse and mould; oxidation products, such as acetaldehyde , sotolon and acetamminofenone, which give smells of honey, wet rag, rotting apple.

As described above, most of the adverse effects, at least at olfactory and taste level, take place even at very low concentrations of contaminants, in nanogram or microgram per litre .

Remediees to avoid the build up of these substances are known in the prior art, but they have not always the desired effect and the build up of those substances may take place in any case and it could be even impossible to prevent it, even only partially.

There are also some curative treatments, but they are very limited in number and reduce their action in a few instances and are often overly severe, since they lead to the simultaneous elimination of positive substances, for example by practicing the absorption with activated coal, virtually completely nonspecific .

In beverages derived from vegetable matrix, the problem of protein instability in the bottle is very frequent, which is due to some protein fractions that remain in solution during the whole process of production, but which tend to aggregate upon heating during transport and distribution of the finished product, causing the appearance of precipitates in the bottle. In some beverages, the presence of these deposits, although of natural source, is refused by the customer and therefore entails a significant depreciation of the product. In wine, the main unstable protein fractions were identified in chitinase and thaumatin-like proteins, or TLP, produced by the vine, especially in response to fungal attack, as well as in lysozyme, used to inhibit the development of lactic acid bacteria.

To avoid the appearance of protein precipitates in the bottle, the wine is normally treated with bentonite, a montmorillonite clay which is kept in slurry in the wine for a certain period, during which it absorbs the unstable proteins that are dragged along the bottom of the container when the bentonite is deposited and, thus, are eliminated through the subsequent decanting or filtration. However, this process is not selective and, when high doses of bentonite are needed to achieve protein stability (even beyond 300g/hl) , the wine treated results depleted in aroma, taste and color. Moreover, the bentonite swells and thus retains considerable quantities of wine and its use results in substantial losses of product (up to 10%) .

Another category of unwanted proteins in wine are the oxydase enzymes, produced from grapes (tyrosinase) or from its pathogen agent (laccase) , which can result in must and wine oxidation phenomena that impairs the wine quality.

WO03/085 002 discloses the synthesis of polymers of cyclodextrin, but it does not disclose any of their application for the purification of beverages.

J. Incl Phenom. Macrocycl . Chem. (2010) 68: 11-122 discloses the use of cyclodextrins for the removal of patulin (a toxic substance) from apple juice. There is no mention of removing substances which are undesired from an organoleptic point of view, nor of a possible use with fermented beverages.

Similarly, Toxins, 2012, 4, 98-109 discloses the use of resins based on β-cyclodextrins and polyurethanes for the removal of ochratoxin A from beverages, including wine, without giving information of a good operation at low pH, or which may suggest that the same substances can work for the removal of substances harmful only from an organoleptic point of view.

The Journal of Chromatography, B, 745 (2000), 83-102 reports the use of cyclodextrins for the separation of substances in various analytical techniques.

WO03/085 002 discloses the use of crosslinked cyclodextrins to remove pollutants from wastewater. The field of wastewater treatment is surely very different from that of the production and organoleptic improvement of fermented beverages of plant origin .

SUMMARY OF THE INVENTION.

The problem underlying the invention is to eliminate as much as possible from beverages of vegetable origin, including grape, wines, vinegars and distilled spirits substances which negatively affect their organioleptic properties, so as to overcome the drawbacks mentioned above and which allows, on the contrary, not to remove from these beverages substances that may anyway be positive and beneficial. This aim is achieved through a process for treating fermented beverages of vegetable origin for the selective removal of molecules contained in them and impairing their organoleptic properties, characterised in that it provides the contact between the beverage and a synthetic polymer, obtained by polymerisation of monomers selected in the group of derivatives from starch. Preferably, such starch derivatives are α-, β-, γ-cyclodextrins and their derivatives and mixtures .

BEST MODE TO CARRY OUT THE INVENTION

As it has been shown, this invention relates to a process for the treatment of fermented beverages of vegetable origin, including the contact between the beverage and a polymer of cyclodextrinj , in order to absorb the harmful substances on the polymer, so as to effectively remove them from the juice or derivative .

The process can be applied to fermented beverages, such as wine, cider, beer and their respective vinegars. It can be applied to distilled spirits, such as grappa, whiskey, vodka, rum, cognac, to fermented beverages made from plant-derived extracts and others.

As polymers polymers obtained by polymerisation in different steps of α-, β-, γ-cyclodextrins and their derivatives can be used. The above mentioned polymers may also be co- polymerised with inorganic substances, such as silica gel via sol-gel. As crosslinking or functionalising agents active carbonyl compounds, organic anhydrides, citric acid, succinic acid, succinic anhydride, tartaric acid, malic acid, tetrabutancarbossilic acid, organic isocyanates, acid 2,2-bis (acrylamido) acetic acid can be used.

Among the active carbonyl compounds carbonyldiimidazol and triphosgene are preferred. Among the organic anhydrides the pyromellitic anhydride is preferred. The polymerisation can also be carried out in the presence of a templating molecule, forming molecularly imprinted polymers.

The polymers, synthetised, as seen, according to the common methods of organic chemistry, are put into contact with the beverage to be treated. The contact can occur in several ways, for example by dipping and suspending of the polymer in the beverage, optionally under stirring and subsequent pouring and filtration after a sufficient time has elapsed to allow the absorption of the harmful substances by the polymers to a sufficient extent.

A possible variant of this embodiment is to mix the polymer with filtering aids, such as diatomaceous earth and cellulose, so that the phenomenon of absorption occurs during the passage of the beverage through the filtration pan. Another possibility is to fill a column, for example a chromatographic column, of polymer, for example in pellets, powder or beads and to pass the beverage to be treated with a flow rate, calculated in order to allow the beverage a residence time in the column that will be sufficient to allow the mentioned absorption. In this case, it is appropriate to equip the column of a filtration system at its end, so as to prevent leakage of the polymer during the treatment. In any case, the insolubility in water of the polymers used in the treatment according to this invention results in them not mixing with the fermented beverage (possibly altering the flavour) , what is particularly important in the case of finest wines and beverages. In case the polymer is suspended, after the time necessary for the absorption elapses, the polymer is left to settle and is then removed by decantation, centrifugation and/or filtration. In case of working in a column, the polymer may be subjected to regeneration cycles, for example by treating with organic solvents, such as ethanol, or with aqueous solutions, having suitable pH and ionic strength. The process in column has the advantage that the loss of beverage caused by the treatment is in any case negligible.

The process according to the present invention can be used for protein stabilisation in fermented beverages, in particular wine. In this case, it is expected that unstable protein fractions and possible undesirable enzymes, present in the beverages themselves, are removed from fermented beverages. The process according to this invention is useful also when it is not able to completely remove' all the unwanted substances from a beverage, in such case, it may still be necessary to treat the beverage with a nonspecific absorbent, such as bentonite or activated charcoal, but the amount of substance used in this case will be considerably less, so that the removal of substances beneficial to the beverage will be reduced to a minimum, with a clear advantage in terms of quality and costs.

Preferably, the polymer is added to the beverage in an amount ranging between 0.1 mg and 200g per hectolitre of beverage .

The effect of treatment according to this invention may in some cases be improved, using for the synthesis of the polymers the so-called molecular imprinting technique. In this case, as previously mentioned, the polymer is synthesised in the presence of a substance (said templating molecule) equal or similar to that which is meant to absorb, at the end of the synthesis, the templating agent is removed by washing. The use of polymers synthesized according to the technique of molecular imprinting is useful in case it is intended to remove molecules, such as, in particular, methoxypyrazines , aldehydes, geosmin, l-oc.ten-3- ol, l-octen-3-one, 2 - methylisoborneol , furfural, benzaldehyde , phenylacetaldehyde, sulfides, thiols, mercaptans, pyridines, pirrolines, sotolon, acetoamminofenone, individually or in combination between them. The treatment with the molecularly imprinted polymers can take place simultaneously either by treating the beverage with different molecularly imprinted polymers or templated polymers in order to absorb simultaneously several unwanted substances. Alternatively, it may be advantageous to perform multiple treatment stages, each one with a different molecularly imprinted polymer, thus removing the unwanted substances, one at each treatment stage.

The polymers to be used in the process according to this invention can be synthesised in various ways. In the following, some synthesis examples are reported. The function of these examples is purely illustrative and it is understood that these examples absolutely do not limit this invention. It should also be borne in mind that these examples are extremely general and they must be adapted from time to time to the particular type of chosen polymer.

SYNTHESIS EXAMPLE 1

Different amounts of carbonylimmidazol are added to a solution of cyclodextrin in dimethylformamide . If it is desired to proceed according to the technique of molecular imprinting, a dose suitable for templating molecule is also added. It is subjected to sonication at room temperature, then causing the cross-linking at 75 ⁰ C in an oil bath, maintaining under stirring for 3 hours, then at room temperature for 24 hours. The polymer is then broken, an excess of water is added to remove any unreacted carbonyldimidazol, filtered, dried and, if necessary, crushed to obtain a powder. It is then washed with water and with ethanol to remove residual reactants and byproducts derived from these chemical reactions.

SYNTHESIS EXAMPLE 2 Aminopropyltrimethoxysilane and tetraethylorthosilicate are solubilised in a basic aqueous solution with ammonium hydroxide at room temperature. Then, cyclodextrins are added to this reaction blend, which is maintained under stirring at 40 ⁰ C, until complete precipitation. Then residual water is eliminated drying the product. The solid is crushed in the desired size and washed with large excess of water and subsequently with ethanol APPLICATION EXAMPLES

In the following, the effects of this invention will be illustrated more in depth, through some application examples, intended only to illustrate and not to limit the invention.

EXAMPLE 1

A synthetic wine contains high amounts of hexanal, a substance deriving from the oxidation of lipids in grapes and which gives the wine an unpleasant grassy smell. It is subjected to a treatment according to the present invention, with a polymera. In test A, the wine is added with the polymer-pCD CDI in powder form, based on β-cyclodextrin crosslinked with carbonyldiimidazol . 3.7 g of polymer per hectolitre of wine are used, corresponding to 3.7 mg of polymer per mg of hexanal, since the concentration of hexanal in the wine is 10 mg/1. The polymer is maintained in a slurry for 24 hours. The results are in Table 1.

Table 1

As it is possible to see from table 1 above, already after only 24 hours a significant reduction of the concentration of hexanal can be reached which can be enough to be outside the detection threshold.

EXAMPLE 2

A synthetic wine containing 2-methoxypyrazine was subjected to the following treatments. Test A polymer aCD-CDI in powder form, based on a-cyclodextrins cross-linked with carbonyldimidazol at a dose of 0.5 mg of polymer per hectolitre of wine containing methoxypyrazine . Test B, the polymer-pCD CDI, based on β-cyclodextrin crosslinked with carbonyldimidazol, under the same conditions of test A. The polymer is maintained in a slurry for 24 hours; the polymers were subjected to molecular imprinting syntetising them in the presence of 2% and 10% of 2-methoxypyrazine and synthesising them without templating. The results are reported in Table 2.

Table 2

imprinting technique allows to significantly increase affinity and specificity of the polymer for a specific compound and shows that, by using the right combination between templating substance and monomere in the synthesis process (in the example, a concentration of 2% is better than that at 10%) the content of a substance in wine can be reduced largely, so as to bring its concentration below the threshold of sense perception.

EXAMPLE 3

Some polymers were added to aqueous solutions of lysozyme at a concentration of 120 mg/1 for a variable time, namely: EB 12 and EB5, nanosponges derived from β-cyclodextrin and PCD- HMDI 1:2, another polymer based on β-cyclodextrins and hexamethylene diisocyanate . The results are reported in Table 3. Table 3

Table 3 shows that some polymers are able to eliminate from the system entirely (or substantially all of) the protein present, even in very rapid times and doses of utilisation of 10-20 g/hl. The results, moreover, show also considerable differences between the different polymers.

EXAMPLE 4 The results of Example 2 were confirmed, using a synthetic wine containing 120 mg/1 of lysozyme. Polymers were left in a slurry in the wine for a period of 12 or 24 hours and then were eliminated by centrifugation, then determining the amount of residual lysozyme in the synthetic wine. The polymers used were EB12 and a pyromellitic nanosponge based on β-cyclodextrins , defined NS-pl8. Also blank tests were carried out, without any added polymer. The results are reported in Table 4.

Table 4

The results of Table 4 show the absorption potential of the two polymers used, in particular of EB12.

'EXAMPLE 5

I

Three different types of white wine and two different types of red wine were subjected to a treatment with NS-pl8. 50 g/hl of polymer were added to the wine and were left to settle on the bottom of the container. Then centrifugation was carried out and then the protein instability of wines was evaluated before and after the treatment. This evaluation was achieved through a hot test, commonly used in cellars and consisting in heating wine at 80°C for 30 minutes and measuring the turbidity in ANTU. The results are summarised in Table 5. Table 5

The results show the reduction of the indices of protein instability in the treated wine, always more than 50% and in certain wines it is even virtually total. In three out of five cases, the wine has become completely stable and the other two took the instability index below the values that require to proceed to treatment with bentonite.

EX/AMPLE 6

A white wine Sauvignon blanc was treated with increasing doses of EB12 and NS-pl8, according to the same procedure described in the previous Examples. The concentration of protein fractions was determined accurately by electrophoresis. The treatment was performed also in the presence of a bentonite of excellent quality, commonly used for these purifications. The results are reported in Table 6.

Table 6

From the results shown in Table 6 the different effectiveness of possible adjuvants is seen; particularly good results are obtained using NS-pl8, while EB12 proved to be the least effective.

It is understood that the invention should not be considered limited to the particular examples illustrated above, which represent only exemplary embodiments of it, but different variants are possible, all within the reach of a skilled person, without departing from the scope of the invention itself, as defined by the appended claims.