Field of the invention

The present invention relates to a new process for producing low-sulphite wine. Background of the invention

Sulphur dioxide (SO2) is an additive which has long been known in the food industry and is widely used especially in the wine industry.

Due to its well-known antiseptic, antimicrobial and antioxidant properties, as well as its relatively low cost, sulphur dioxide is added to must and/or wine during the winemaking process to prevent undesirable oxidation and browning, and to ensure the quality of the wine produced from a sanitary point of view. Over the last two centuries, winemaking techniques have undergone rapid development thanks to improvements in the management of sulphur dioxide during winemaking and packaging.

Residual sulphur dioxide occurs in food in various forms, including in particular the molecular form (SO ₂ ) and sulphite ions (SO ₃ ² ) resulting from dissociations of the molecular form, as well as further derived salt forms, compounds which are referred to collectively as 'sulphites' in the following.

Despite the advantageous properties that may be attributed thereto, sulphites have been classified as toxic and poisonous compounds, particularly because of their allergenic character. A number of scientific studies have also linked the intake of sulphites through food and drink with the possible occurrence of oncogenetic phenomena.

For these reasons, the World Health Organisation has established a maximum daily intake of sulphites of 0.7 mg/kg body weight, while the lethal dose has been set at 1 .5 g/kg body weight. As a result, the European Union has established a legislative framework obliging manufacturers to indicate on the label quantities exceeding 10 mg/I of residual sulphur dioxide in food and beverages (EU Regulation 1169/2011).

In recent years there has therefore been a considerable increase in demand for wines produced with very low or no sulphites, which has led wineries to look for valid alternatives to their use in order to prevent the health problems outlined above, while ensuring high quality standards of the wines produced in terms of microbiological and oxidative control. It should also be noted that some sulphur dioxide is also produced spontaneously by the fermentation yeasts conventionally used in winemaking, in concentrations of up to 100 mg/I depending on the specific strain and the composition of the must.

Related art

Among the possible solutions to reduce the use of sulphites in winemaking processes, numerous chemical products have been investigated, such as ascorbic acid, lysozyme, bacteriocins, dimethyl carbonate, glutathione, phenolic compounds and chitosan, as well as physical means such as pulsed electric fields (PEF), ultrasound, ultraviolet irradiation and high hydrostatic pressure (HP).

Among the various alternatives investigated, chitosan proved to be particularly promising due to its satisfactory antimicrobial, antiseptic and antioxidant power, in combination with high biocompatibility and non-toxicity.

Chitosan is a naturally occurring polysaccharide extracted from chitin, which is in turn obtained from shells of sea invertebrates or extracted from mushrooms. Today chitosan is widely used in pharmaceutical and biomedical applications. Chitosan extracted from the fungus Aspergillus niger is the only type that has so far been approved by the International Organisation of Vine and Wine as a product that can be used in oenology (OIV-OENO 336B- 2009).

WO 2011/157955 A2 describes an additive in powder form based on chitosan of fungal origin, having an average particle size between 0.1 and 200 pm. The additive is insoluble in water and is added in suspension to a liquid foodstuff to be treated, e.g. fermenting wine.

The document aims at specifically contrasting the yeast strain Brettanomyces and does not appear to seek for protection against other types of must alteration during winemaking. The paper suggests that the activity of chitosan should be as targeted as possible to prevent the inhibition of useful bacteria and yeasts during the fermentation and ageing of wines.

The additive disclosed in this document therefore does not appear to be optimised to provide, by itself, wide-ranging and effective microbiological stability throughout the whole winemaking procedure. In addition, the disclosure does not provide sufficient evidence that the quantities of chitosan used provide effective protection against oxidation.

WO 2013/066200 A2 discloses a winemaking process without the addition of sulphur dioxide, which includes the preparation of a chitosan-based film that is placed within the bottle during bottling so that it is in contact with the wine. The film is deliberately used only after fermentation to prevent its use in this step from altering the organoleptic characteristics of the wine.

Contrary to what is suggested in the aforementioned documents of the prior art, the Applicant believes instead that it is important to exercise an effective microbiological control also during the fermentation step, in order to counteract the uncontrolled proliferation of yeasts and micro-organisms that could establish undesirable alternative fermentations.

However, the Applicant has verified that high amounts/concentrations of chitosan on the one hand result in increased antimicrobial efficacy, but on the other hand may cause an undesirable inhibition of the yeasts selected for fermentation, thus lowering the quality of the wine produced.

Summary of the invention

An objective of the present invention is to provide a winemaking process that does not involve the use of sulphite-containing additives and that allows to solve the drawbacks of the processes of the prior art, by performing an effective broad-spectrum microbiological control before, during and after fermentation, while ensuring high quality standards of the wine produced.

A further objective of the present invention is to provide a winemaking process that can be applied in a versatile manner to the production of different types of wine (e.g. red and white wines).

A further objective of the present invention is to provide a simplified and cost-effective winemaking process that can be applied to industrial-scale production.

A further specific objective of the present invention is to obtain a wine with a shelf life of at least 12 months.

In particular, the inventors perceived and experimentally found that the above-mentioned problems related to the use of chitosan-based products in a winemaking process can be overcome by combining their use with a thermo-maceration step, during which the grapes are subjected to a temperature and pressure regime that allows the undesirable microbial load to be lowered to essentially zero before the fermentation step begins. Thus, according to a first aspect thereof, the invention relates to a process for producing a low-sulphite wine, comprising the steps of: a) providing crushed grape; b) submitting said crushed grape to thermo-maceration, by heating it to a temperature comprised between 50 and 90°C, preferably between 75 and 87°C, more preferably between 82 and 85°C; c) extracting a must from said crushed grape; d) fermenting said must, obtaining wine; and e) adding a chitosan-based product to at least one of the crushed grape, the must and the wine.

Within the context of the present description and following claims, all the numerical magnitudes indicating quantities, parameters, percentages, and so on are to be considered preceded in every circumstance by the term “about” unless indicated otherwise. Further, all the ranges of numerical magnitudes include all the possible combinations of maximum and minimum numerical values and all the possible intermediate ranges, as well as those indicated below.

Within the scope of this description and subsequent claims, and as noted above, the term "sulphites" is broadly used to include sulphur dioxide (SO ₂ ) and sulphite ions (SO ₃ ² ) derived therefrom, as well as further derived salt forms. Within the scope of this description and in subsequent claims, the expression "crushed grape" means grapes that have undergone conventional crushing operations to give a mixture of crushed grapes, pulp, pomace, grape juice and possibly stems.

Within the scope of this description and subsequent claims, the term "must" means a liquid grape-based product, not yet fermented or only partially fermented, obtained by separating the liquid component from the solid components such as pomace and stems, if present, in the crushed grapes.

In this description and in the subsequent claims, the term "wine" means the raw product obtained at the end of the must fermentation step or, depending on the circumstances, the finished product obtained at the end of the overall winemaking process. Within the scope of this description and subsequent claims, the expression "low-sulphite wine" means a wine, understood as a finished product, with a sulphite content of less than 10 mg/I. Similarly, the expression "SC free process" will sometimes be used in this document to designate a process for the production of low-sulphite wine.

In the process according to the invention, the steps of thermo-maceration and of use of chitosan cooperate in preserving the crushed grapes, the must and subsequently the wine from possible alterations caused by undesirable microorganisms and by the initiation of oxidative phenomena. The thermo-maceration step, carried out by heating the crushed grapes to the indicated temperatures, effectively reduces the microbial load in the grapes and in the must extracted from them before fermentation begins. In this way, the provision of the preliminary thermo-maceration allows a subsequent reduced and more targeted use of chitosan, so that the negative microbial load of the must can be effectively controlled on a broad spectrum during fermentation and in any subsequent processing steps up to the bottling of the wine obtained, without negatively interfering with the activity of the fermentation yeasts.

The combination of the steps of thermo-maceration and of addition of the chitosan-based product advantageously allows to completely avoid the use of sulphur dioxide additives during winemaking. The process of the invention thus results in wines which containing no sulphur dioxide other than the minimum residual amount, well below the legal limit of 10 mg/I, which is produced spontaneously by the yeasts during fermentation.

Most advantageously, the process of the invention applies indiscriminately to the production of low-sulphite red and white wines of different types and qualities depending on the starting grapes. In all cases, the wines produced are found to possess qualitative and organoleptic characteristics at least comparable to those of wines produced according to known SO2- free winemaking processes.

Moreover, the process developed is effectively applied to large-scale production, and the wines produced have an average shelf life of at least 12 months.

The inventors have also found that the provision of the step of thermo-maceration of the crushed grapes advantageously increases the dry extract of the wine produced compared to known SC ree processes, conferring more structure and body to the wine, and raising its content of naturally antioxidant molecules such as polyphenols and anthocyanins.

When the process is carried out on red grapes for the production of red wine, the thermo- maceration step brings the additional advantage of facilitating the extraction from the skins and the release into the must of colour, resulting in wines with a more intense colour.

Instead, when the process is carried out starting from white grapes for the production of white wine, the thermo-maceration step advantageously allows to obtain fuller-bodied white wines with a higher polyphenol and anthocyanin content than white wines produced according to known white wine making processes, in which the pomace is typically separated almost immediately from the liquid component in order to prevent maceration.

The present invention can have, in one or more of its aspects, or one or more of the preferred features reported below, which can be combined with one another as preferred according to the application requirements.

Preferably, the grapes prepared in step a) are destemmed crushed grapes.

In this description and in the accompanying claims, "destemmed crushed grapes" or sometimes in short "crushed grapes" means grapes which have been subjected to conventional destemming or crushing operations to give a mixture of crushed grapes, pulp, pomace and grape juice, devoid of stems.

The exclusion from the crushed grapes of stems, which are rich in less noble tannins, prevents the development of excessively astringent, bitter and/or herbaceous notes in the wine produced.

As indicated above, the starting grapes can be red grapes or white grapes of any type and/or variety. When red grapes are used, the final product obtained is red wine. When white grapes are used, the final product obtained is white wine.

Preferably, the thermo-maceration step b) has a duration comprised between 1 and 8 minutes, more preferably between 1.5 and 4 minutes, even more preferably of about 2 minutes.

The Applicant has verified that these times allow for the effective inactivation of the harmful bacterial load present in the grapes, while preventing deterioration of the grapes caused by too prolonged exposure thereof to heat.

Preferably, the thermo-maceration step b) is carried out continuously in a thermo maceration plant, including a first dynamic heat exchanger.

By operating continuously, heating of the must is faster as it does not require the must to remain in a vessel for heating. More preferably, said first dynamic heat exchanger is chosen from a multi-tubular heat exchanger and a coaxial heat exchanger, more preferably being a multi-tubular heat exchanger.

Preferably, immediately after the thermo-maceration step b), the process further comprises a step f) of subjecting the crushed grapes to a vacuum condition.

More preferably, in said step f), the must is subjected to a negative pressure comprised between -1.1 and -0.7 bar, even more preferably of around -0.9 bar.

In that case, preferably the thermo-maceration step b) and the subsequent step f) of subjecting the crushed grapes to a vacuum condition are performed continuously in a thermo-maceration plant of the flash detente type.

Preferably, in this case, in accordance with the flash detente technology, in the thermo maceration step b) the crushed grapes pass into the first dynamic heat exchanger in which they are heated to the operating temperature included in the above mentioned ranges. In the next step e), the heated crushed grapes are then continuously introduced into a chamber subjected to a high vacuum, within the preferred pressure ranges indicated above. Passage through the vacuum chamber causes the crushed grapes to cool almost instantaneously, and the steam generated condenses. The condensates and drained juices extracted from the crushed grapes are then pumped out of the chamber and continue along the line for further processing.

The application of negative pressures, in particular using the briefly described flash detente technology, allows more effective extraction of desirable substances such as polyphenols, anthocyanins and polysaccharides, loading the wine with fruity, rounded aromas. Furthermore, in the case of winemaking from red grapes, the application of a high vacuum during the thermo-maceration step further enhances the extraction of colour and organoleptically relevant substances from the macerating skins in the must.

Preferably, in the thermo-maceration step b) the crushed grapes are pumped into the thermo-maceration plant, possibly of the flash detente type, at a flow rate comprised between 10 and 18 t/h, more preferably between 12 and 17 t/h, even more preferably of about 16 t/h.

Preferably, step c) of extracting the must from the crushed grapes comprises Ci) subjecting the thermo-macerated crushed grapes to draining. Draining is an operation that involves circulating the crushed grapes in static or moving frames with perforated walls, so that the liquid part of the crushed grapes drains away by gravity.

Alternatively or additionally, step c) of extracting the must from the crushed grapes includes C ₂ ) subjecting the thermo-macerated crushed grapes to pressing.

Pressing involves subjecting the thermo-macerated crushed grapes to compression in an oenological press in order to squeeze the macerated pomace to extract all the residual solid component.

Preferably, step c) of extracting the must from the crushed grapes comprises C3) subjecting the thermo-macerated crushed grapes to pressing and/or filtration draining.

Preferably, the step C3) of filtering the thermo-macerated crushed grapes is performed using a tangential filter, more preferably comprising ceramic membranes.

Step C3) of filtering the must removes the solid particles remaining in suspension in the liquid extracted by pressing and possible draining. In other words, in step c) of extracting the must, the crushed grapes undergo one or more operations to separate the solid components, such as pomace and possibly stems, from the liquid part that makes up the must.

Preferably, before the start of the fermentation step d), the must is cooled to a temperature comprised between 15° and 30°C. The Applicant has verified that within this temperature range the subsequent fermentation proceeds in a linear manner, without being subject to any halting or slowing down due to inhibition of yeast activity.

More preferably, before the start of the fermentation step d), the must is cooled to a temperature comprised between 16° and 18°C. At temperatures within this range, the must has a lower tendency to develop higher alcohols which, if present in excessive quantities, can detract from the freshness and give the wine overly herbaceous aromas.

Preferably, said cooling of the must is achieved by means of a second dynamic heat exchanger. More preferably, said second dynamic heat exchanger is chosen from a multi-tubular heat exchanger and a coaxial heat exchanger, more preferably being a multi-tubular heat exchanger.

Preferably, the must fermentation step d) is activated by inoculation of a selected fermentation yeast.

In this description and the appended claims, the term "brewer's yeast" in the singular form is intended to broadly encompass, as the case may be, a single brewer's yeast, or a mixture of different brewer's yeasts, possibly also of different types, strains and/or species.

Preferably, before inoculation into the must, the fermentation yeast is rehydrated in a warm aqueous solution at a temperature comprised between 25° and 35°C.

In oenology, the technique of rehydrating and reactivating the fermentation yeast in a warm aqueous solution is known as the fermentation starter or pied de cuve technique, and constitutes a conventional practice in the oenological field, and therefore within the reach of a person skilled in the art. The aqueous solution containing the rehydrated and therefore activated yeast is inoculated into the must, initiating the fermentation step d).

Preferably, the fermentation yeast used in the must fermentation step d) belongs to the Saccharomyces cerevisiae species.

Preferably, the fermentation yeast used in the must fermentation step d) belongs to a low sulphite-producing strain.

This limits the production of sulphites during fermentation of the must and, consequently, the residual sulphite content in the finished product.

Commercially available low sulphite-producing fermentation yeasts which have been found to be particularly suitable for use in the process according to the invention are, by way of non-limiting example: Aleaferm Arom made by Alea Evolution S.r.l., Selectys® La Marquise made by Oenofrance, Lalvin ICV Okay® made by Lallemand Inc, Zymaflore® Xpure made by Laffort®, Selectys® Italica AM37 made by Oenofrance, IOC BE FRUITS made by Institut Oenologique de Champagne, IOC BE THIOLS made by Institut Oenologique de Champagne, Lalvin ICV Opale® made by Lallemand Inc. Preferably, the must fermentation step d) has a duration comprised between 8 and 15 days, more preferably between 10 and 13 days.

Preferably, the chitosan-based product is an additive, more preferably in powder form.

Preferably, in step e) above, the chitosan-based product is added to the must. In other words, in this case step e) of adding the chitosan-based product is only performed after step c) of extracting the must from the crushed grapes.

By adding the chitosan-based product to the must, the action of possible pollutants or microbes that may have occurred, for example as a result of must extraction operations (e.g. draining, pressing, filtration) is effectively counteracted. Furthermore, using the product on the must prevents exposing the chitosan to the temperature conditions of thermo-maceration -and possibly the vacuum conditions of the subsequent step f), if present-1 which may partially alter the properties thereof and compromise the antimicrobial and antioxidant efficacy thereof.

Preferably, the total amount of chitosan-based product added to the must is comprised between 25 and 80 g/hl, more preferably between 30 and 60 g/hl of must.

Preferably, the aforesaid step e) comprises ei) adding said chitosan-based product to the must prior to the activation of the must fermentation step d).

In fact, it is of fundamental importance that the must is in the best possible conditions even during the pre-fermentation step, in which it is particularly susceptible to attacks from bacteria, changes caused by microbial activities and oxidation. For this reason, the use of chitosan has a protective anti-oxidative and anti-microbial action that prevents spoilage of the must from the start of fermentation, and then promotes the establishment of proper fermentation by the selected fermentation yeast only.

Alternatively or additionally, step e) includes e _å ) adding said chitosan-based product to the must during the fermentation step c).

In this way, the chitosan provides antimicrobial protection from possible contamination of the must during already established fermentation and counteracts the oxidative mechanisms caused by the metabolism of fermenting yeast. Preferably, in this case the chitosan-based product is added to the must in a second half of the total time of the fermentation step.

In this way, the must is better protected after the end of fermentation, even during any subsequent processing of the raw wine obtained at the end of fermentation. In preferred embodiments, the chitosan-based product is added to the must two or more times during the fermentation step c).

Thus, by increasing the frequency of addition of the chitosan-based product, it is possible to decrease the amounts in each individual addition, thus prolonging its effectiveness over time and minimising the risk of inhibiting fermentation yeast activity. Alternatively or additionally, step e) comprises e3) adding said chitosan-based product to the raw wine obtained at the end of the fermentation step d). For example, the chitosan- based product can be added to raw wine during its storage pending further processing or bottling. In this way, the protective action of the chitosan is further extended right up to the bottling of the finished product. In preferred embodiments, the chitosan-based product comprises an additive for stabilising the protein component of the must.

The addition of the chitosan-based product also containing the aforesaid stabilising additive to the must enables a partial clarification of the must to be carried out already in the pre fermentation step and/or during the fermentation step c), promoting the precipitation and sedimentation of the protein complex of the must and guaranteeing further effective protection against oxidative phenomena.

By way of example, the stabilising additive may comprise one or more of the additives of the group consisting of bentonite, gelatine, albumin, sol-silica, preferably bentonite.

Preferably, the process according to the invention further comprises one or more of the steps of: g) addition of one or more antioxidant additives to the must; h) clarification of the must; i) tartaric stabilization of the must; j) filtration of wine; and k) bottling.

Preferably, the at least one antioxidant additive of step g) comprises tannin. Tannin greatly enhances the antioxidant action already exerted by the chitosan.

When the process is carried out starting from red grapes, ellagitannin is preferably used.

Ellagitannins, extracted from oak wood, besides showing excellent antioxidant properties, indirectly contribute to the stabilisation of the colouring matter in red wine by catalysing the formation of acetaldehyde during ageing of wine, which in turn promotes increased colouring in the wine. Ellagitannins, especially when extracted from precious wood sources, are able to significantly enhance the sensory and organoleptic qualities of the red wines produced.

When the process is carried out starting from white grapes, gallic tannin is preferably used. This type of tannin is particularly effective in preventing oxidation when making white wine, as it is particularly unreactive towards polyphenols.

Gallic tannins act as clarification aids for must, as they are very reactive towards the proteins present in must and wine, in particular towards thermo-unstable proteins which frequently give rise to protein instability and browning, especially in musts intended for white wine making. Gallic tannins are also highly reactive towards oxidase enzymes such as laccase and tyrosinase, which are also responsible for the darkening of white musts.

Furthermore, from a sensory and organoleptic point of view, the use of gallic tannins confers good body and tannic structure to the white wine produced, while offering softness and balance of taste.

Preferably, step h) of clarifying the must includes hi) adding one or both of gelatine and bentonite to the must.

More preferably, step h) of clarifying the must also comprises h ₂ ) filtering the must, more preferably using a tangential flow filter, even more preferably comprising ceramic membranes.

Preferably, step i) of tartaric stabilisation of the must comprises adding one or more of the additives chosen from potassium polyaspartate, carboxymethylcellulose (CMC) and cationic resins to the must.

Preferably, step i) of tartaric stabilisation step i) is performed cold, more preferably by bringing the must to a temperature comprised between -4° and 7°C, even more preferably between about 0° and 6°C, even more preferably of about 4°C.

Preferably, the wine filtration step j) comprises microfiltration.

More preferably, the wine filtration step j) is carried out using a filter comprising polymeric membranes.

Preferably, the wine filtration step j) is carried out just before bottling step k).

The pre-bottling wine filtration step j) removes processing residues from the wine, such as sediment from tartaric stabilisation, any clarification residue, and the undissolved chitosan residue. Detailed description of currently preferred embodiments

In order to verify the performance of the process according to the invention, various experiments were carried out, some of the results of which are set out below, which are intended to be illustrative and not limiting of the present invention.

EXAMPLE 1 - Red wine production process Sangiovese red grapes (180 t) were harvested and destemmed in a destemming machine (DIEMME Kappa 90), obtaining 171 t of destemmed crushed grapes including a liquid component of juice and a solid component consisting of pulp and pomace.

The destemmed crushed grapes obtained were subjected to thermo-maceration in a first multi-tubular dynamic heat exchanger, and then introduced into a vacuum chamber in a flash detente thermo-maceration plant (Biothermo system, Della Toffola), setting the parameters listed in Table 1 :

Table 1 - Thermo-maceration and passage in vacuum chamber The destemmed crushed grapes, cooled to around 35°C by effect of the passage in the vacuum chamber, were drained and pressed continuously (DIEMME draining machine, maximum flow rate 14 t/h) and filtered through a ceramic membrane tangential flow filter (OMNIA Della Toffola tangential flow filter, filtering surface area 60 m ² , maximum flow rate 25 hl/h), thus eliminating the solid components and obtaining a must.

The must was further cooled to a temperature of approximately 17°C in a second multi tubular dynamic heat exchanger, and distributed in fermentation tanks (maximum capacity 1200-1500 hi) equipped with an external cooling jacket and automated temperature control. Before the beginning of fermentation, a powdered additive based on chitosan and bentonite (No[OX], made by the Institut Oenologique de Champagne), ellagitannin (TANIN VR SUPRA®, made by Laffort®) and an antioxidant additive based on yeast lysates (PURE LEES™ Longevity, made by Lallemand Inc.) were added to the must.

Fermentation was activated by preparing a fermentation starter by means of conventional piedde cuve fermentation techniques, by rehydrating a low sulphite-producing yeast (Lalvin ICV Opale®, made by Lallemand Inc.) in a 3% aliquot of must at approximately 30°C. The fermentation starter containing the activated yeast was then slowly added to the must. Once fermentation had started, an additional antioxidant and yeast nutrient additive (Superstart® Spark, made by Laffort®) was added to the must.

Fermentation was carried out at a controlled temperature of around 17°C for approximately 12 days until the sugar component had finished.

After 6 days, about halfway through fermentation, the must was further enriched with nutrient/antioxidant additives (from IOC ActivitO and IOC Activit, made by the Institut Oenologique de Champagne).

For clarification purposes, bentonite was added to the must on day 4, and bentonite again in combination with gelatine on day 12. The must was then subjected to filtration with a tangential flow filter (Pall® Oenoflow tangential flow filter, polysulphone membrane, maximum flow rate 50 hl/h) to remove precipitates.

On day 12, an additional powdered additive based on chitosan (IOC Sentinel, made by the Institut Oenologique de Champagne) and ellagitannin (TANIN VR SUPRA®, made by Laffort®) was added to the wine.

The raw wine thus obtained was then subjected to tartaric stabilisation by the addition of potassium polyaspartate, causing the precipitation of potassium bitartrate.

The raw wine was then subjected to microfiltration with polymeric membranes (Sartorius SARTOFLOW® 10 system) at a flow rate of 40hl/h. At the end of the process, 1260 hi of Sangiovese red wine was obtained. 100 hi of the wine produced was stored in a storage tank, while the remainder was packed partly in 0.5 L Tetra Pak® cartons (Tetra Pak® A3/Flex packaging machine), and partly in 0.75 L bottles (MBF bottling machine, 15000 pieces/h). Table 2 below shows the quantities of the various ingredients / oenological additives used in the process as outlined above.

Table 2 - Oenological additives used in the production of red wine

EXAMPLE 2 - White wine production process

White Trebbiano grapes (110 t) were harvested and crushed and destemmed in a destemmer-crusher (DIEMME Kappa 90), obtaining 104.51 of destemmed crushed grapes including a liquid component of juice and a solid component consisting of pulp and pomace. The destemmed crushed grapes obtained were subjected to thermo-maceration in a first dynamic heat exchanger of the multi-tubular type, and then introduced into a vacuum chamber, in a flash detente thermo-maceration plant (Biothermo system, Della Toffola), setting the same parameters as those shown above in Table 1.

The destemmed crushed grapes, cooled to around 35°C by effect of the passage in the vacuum chamber, were drained and pressed continuously (DIEMME draining machine, maximum flow rate 14 t/h) and filtered through a ceramic membrane tangential flow filter (OMNIA Della Toffola tangential flow filter, filtering surface area 60 m ² , maximum flow rate 25 hl/h), thus eliminating the solid components and obtaining a must.

The must was further cooled to a temperature of approximately 17°C in a second multi tubular dynamic heat exchanger, and distributed in fermentation tanks (maximum capacity 1200-1500 hi) equipped with an external cooling jacket and automated temperature control. Before the beginning of fermentation, a powdered additive based on chitosan and bentonite (No[OX], made by the Institut Oenologique de Champagne), gallic tannin (Oenotannin® Excellence Gold White, Oenofrance) and an antioxidant additive based on yeast lysates (PURE LEES™ Longevity, made by Lallemand Inc.) were added to the must.

Fermentation was activated by preparing a fermentation starter by means of conventional piedde cuve fermentation techniques, by rehydrating a low sulphite-producing yeast (Lalvin ICV Opale®, made by Lallemand Inc.) in a 3% aliquot of must at approximately 30°C. The fermentation starter containing the activated yeast was then slowly added to the must. Once fermentation had started, an additional antioxidant and yeast nutrient additive (Superstart® Spark, made by Laffort®) was added to the must.

Fermentation was carried out at a controlled temperature of around 17°C for approximately 12 days until the sugar component had finished.

About halfway through fermentation, 6 days after the start of fermentation, the must was further enriched with nutrient/antioxidant additives (IOC Activit O and IOC Activit, made by the Institut Oenologique de Champagne).

For clarification purposes, bentonite was added to the must on day 4 of fermentation, and bentonite again in combination with gelatine on day 12. The must was then subjected to filtration with a tangential flow filter (Pall® Oenoflow tangential flow filter, polysulphone membrane, maximum flow rate 50 hl/h) to remove precipitates.

On day 12, an additional powdered additive based on chitosan (IOC Sentinel, made by the Institut Oenologique de Champagne) and gallic tannin (Oenotannin® Excellence Gold White, Oenofrance) was added to the wine.

The raw wine thus obtained was then subjected to tartaric stabilisation by the addition of potassium polyaspartate, causing the precipitation of potassium bitartrate.

The raw wine was then subjected to microfiltration with polymeric membranes (Sartorius SARTOFLOW® 10 system) at a flow rate of 40hl/h.

At the end of the process, 800 hi of white Trebbiano wine was obtained. 150 hi of the wine produced was stored in a storage tank, while the remaining part was packed partly in 0.5 L Tetra Pak® cartons (Tetra Pak® A3/Flex packaging machine), and partly in 0.75 L bottles (MBF bottling machine, 15000 pieces/h).

Table 3 below shows the quantities of the various ingredients / oenological additives used in the process as outlined above. Table 3 - Oenological additives used in the production of white wine

EXAMPLE 3 - Analysis and shelf-life test on unpackaged red wine

The portion of Sangiovese red wine produced according to Example 1 stored in the storage tank was subjected to chemical, quality and organoleptic analyses.

The measurements were made on samples taken from the storage tank at two distinct time points T 1 (at the start of storage, approximately 6 days after the end of fermentation) and T2 (6 months after the start of storage), in order to assess the shelf-life of the wine in an unpackaged condition. The parameters analysed, their measurement methods and the results obtained are shown in Table 4 below. Table 4 - Results of analyses on unpackaged red wine

The results shown in Table 4 show that the red wine produced has a residual sulphite content below the legal limit of 10 mg/I for labelling, and is therefore classifiable as a low- sulphite or SC>2-free wine. In addition, all the chemical/physical parameters assessed were found for all the measurements carried out to be within the respective compliance ranges dictated by the IGT standard and/or by legal requirements, indicating that the unpackaged red wine has features comparable to those of wines produced using traditional winemaking processes.

Moreover, small variations in the parameters are observed between the first and second measurements taken at T 1 and T2, indicating that the chemical and physical characteristics of the red wine stored in the storage tank remained more or less unchanged over the 6 months of observation.

In particular, the non-significant variation in the optical parameters (Colour intensity and Hue) between the two measurements shows that the red wine was not subject to cloudiness caused by oxidative phenomena, and did not lose its original colour and clarity, which further confirms the excellent state of preservation maintained by the unpackaged red wine over the 6-month observation period. EXAMPLE 4 - Analysis and shelf-life test on packaged red wine

Sangiovese red wine produced and packaged according to Example 1 was subjected to chemical, quality and organoleptic analyses.

For each batch of wine packaged in 0.75 L bottles and 0.5 L Tetra Pak® cartons, respectively, and appropriately stored, measurements were taken on a sample basis on the contents of the bottles and cartons at three distinct time points T 1 (the day after packaging), T2 (2 months after packaging) and T3 (13 months after packaging), in order to evaluate the shelf-life of the wine in the packaged condition.

The parameters analysed, their measurement methods and the results obtained are shown in Table 5 below.

Table 5 Results of analyses on packaged red wine As already discussed above in Example 3, the red wine produced has a residual sulphite content below the legal limit of 10 mg/I for labelling, and is therefore classifiable as low- sulphite or SC>2-free wine.

The chemical/physical parameters assessed were found to be within the respective compliance ranges dictated by the IGT standard and/or by the legal requirements, indicating that the packaged red wine has characteristics comparable to those of wines produced using traditional winemaking processes.

Furthermore, from the results shown above in Table 5, it can be seen that all the chemical/physical parameters measured underwent small variations between the first, second and third measurements taken at T1 , T2 and T3, indicating that the red wine produced keeps substantially unchanged in both packaging methods (bottle/carton) for at least 12 months.

As with the unpackaged red wine, the non-significant variation in the optical parameters (Colour intensity and Hue) over the first two measurements shows that the packaged red wine was not subject to cloudiness caused by oxidative phenomena, and did not lose its original colour and clarity. A slightly more significant increase in hue, slightly above the compliance limit, was only detected at month 13, but already beyond the product's 12-month shelf life.

EXAMPLE 5 - Analysis and shelf-life test on unpackaged white wine The portion of Trebbiano Sangiovese white wine produced according to Example 2 stored in the storage tank was subjected to chemical, quality and organoleptic analyses.

The measurements were made on samples taken from the storage tank at two distinct time points T 1 (at the start of storage, approximately 6 days after the end of fermentation) and T2 (6 months after the start of storage), in order to assess the shelf-life of the wine in an unpackaged condition.

The parameters analysed, their measurement methods and the results obtained are shown in Table 6 below. Table 6 - Results of analyses on unpackaged white wine

The results shown in Table 6 show that the white wine produced has a residual sulphite content below the legal limit of 10 mg/I for labelling, and is therefore classifiable as a low- sulphite or SC ree wine.

In addition, all the chemical/physical parameters assessed were found for all the measurements carried out to be within the respective compliance ranges dictated by the IGT standard and/or by the legal requirements, indicating that the unpackaged white wine has characteristics comparable to those of wines produced using traditional winemaking processes.

Moreover, small variations in the parameters are observed between the first and second measurements taken at T 1 and T2, indicating that the chemical and physical characteristics of the white wine stored in the storage tank remained more or less unchanged over the 6 months of observation. In particular, the non-significant variation in optical density between the two measurements shows that the white wine was not subject to cloudiness caused by oxidative phenomena, and retained its original clarity, which further confirms the excellent state of preservation maintained by the unpackaged white wine over the 6 months of observation. EXAMPLE 6 - Analysis and shelf-life test on packaged white wine

Trebbiano white wine produced and packaged according to Example 2 was subjected to chemical and organoleptic analysis.

For each batch of wine packaged in 0.75 L bottles and 0.5 L Tetra Pak® cartons, respectively, and stored appropriately, measurements were taken on a sample basis on the contents of the bottles and cartons at three distinct time points T 1 (the day after packaging), T2 (2 months after packaging) and T3 (13 months after packaging), in order to evaluate the shelf-life of the wine in the packaged condition.

The parameters analysed, their measurement methods and the results obtained are shown in Table 7 below.

Table 7 - Results of analyses on packaged white wine

As already discussed above in Example 5, the white wine produced has a residual sulphite content below the legal limit of 10 mg/I for labelling, and is therefore classifiable as low- sulphite or SC>2-free wine. The chemical/physical parameters assessed were found to be within the respective compliance ranges dictated by the IGT standard and/or by the legal requirements, indicating that the packaged white wine has characteristics comparable to those of wines produced using traditional winemaking processes. Furthermore, from the results shown above in Table 5, it can be seen that all the chemical/physical parameters measured underwent small variations between the first, second and third measurements taken at T1 , T2 and T3, indicating that the white wine produced keeps substantially unchanged in both packaging methods (bottle/carton) for at least 12 months. As with the unpackaged white wine, the non-significant change in optical density over the first two measurements shows that the packaged white wine was not subjected to cloudiness caused by oxidative phenomena, and did not lose its original clarity. A more significant increase in optical density, above the compliance limit, was only detected at month 13, but already beyond the product's 12-month shelf life.

EXAMPLE 7 - Sensory analysis

Samples of red wine and white wine, produced in accordance with Examples 1 and 2 and packaged in 0.5 L Tetra Pak® carton, were subjected to tasting analysis (in particular visual, olfactory and taste-olfactory) in order to assess their sensory characteristics. Samples were taken from the contents of the cartons at three distinct time points T 1 (the day after packaging), T2 (2 months after packaging) and T3 (6 months after packaging), and immediately evaluated. The samples were blindly submitted to a panel of judges who awarded between 1 and 10 points for each sensory parameter of interest.

For each sample, the overall score was calculated by adding up the median of the points awarded by all panel members in relation to each parameter.

The results of the sensory analysis are shown in Table 8 below.

Table 8 - Results of sensory analysis

The overall score awarded by the panel of judges was well above the sufficiency level for all the samples evaluated, set at a score of 65, demonstrating that the process of the invention results in high quality wines also from a tasting and sensory point of view. Comparative experimental tests carried out by the Applicant have shown that the combination of the thermo-maceration steps and the use of chitosan synergistically cooperate in preserving the destemmed crushed grapes and/or the must and/or the wine from possible alterations caused by undesirable microorganisms and from the initiation of oxidative phenomena during the winemaking process.