Long shelf life single-serve packaged wine

Abstract

A method of making a long shelf-life package containing wine is described, enabling it to have a long shelf-life and to remain indistinguishable from the same wine kept in a bottle. The method comprises encapsulating single-serve amounts of the wine into a series of flexible-walled containers, and sealing the amount therein substantially to fill each container, placing the filled containers into a holding container, placing the holding container into a pressure vessel, altering the pressure in the tank for a time period sufficient essentially to create a differential between any microbial organisms and their surrounding environment within each filled container in order to inactivate them, removing the filled containers from the holding container, and packaging them for shipping.

Description

[0001] LONG SHELF LIFE SINGLE-SERVE PACKAGED WINE

[0002] Technical Field

[0003] This invention relates to packaging wine to make single-serve packages with a long shelf life. A single-serve package is defined as a container which holds a volume of wine that is designed to be consumed by one or more people on a single occasion, rather than being in the form of a resealable package, for exam pie a wine box, which can be opened and then closed to enable the wine in it to be consumed over a day or longer.

[0004] Background of the Invention

[0005] Wine is a particularly challenging beverage to pack for numerous reasons.

[0006] Firstly, the chemical makeup of the hundreds of thousands of different styles of wines available on the market at any one time is highly varied, leading to a significant number of different paths to spoilage.

[0007] Secondly, wine is incredibly sensitive to oxygen contact, with both too much and too little offering different challenges. Too much will destroy fragile flavours, but too little will lead as the wine ages or matures to the development of undesirable compounds such as hydrogen sulphide.

[0008] Thirdly, wine is vulnerable to damage from a plurality of different microbial elements and the legislative environment means that many chemical preservatives are not approved for use in their manufacture.

[0009] The generally accepted biggest challenge for wine is oxygen contact. Oxygen reacts with volatile aromatic compounds such as thiols, polyphenols that define colour, flavour and tannins, and alcohol, forming aldehydes, quinones and other undesirable chemicals. Traditionally, sulphur dioxide, in the form of potassium metabisulphite, is added to the wine to act as an antioxidant, binding to the oxygen before it reacts with the other components.

[0010] By far the most used way of preserving a wine against deterioration once made is to bottle it, using glass bottles. Various standard sizes are specified by regulation, by far the most used being 750ml capacity. The wine once made is filled into the bottle (usually immediately after the interior of the bottle has been sparged with an inert gas) and then corked, using a traditional natural cork bung or a synthetic one, in either case usually leaving no headspace. The 750ml bottle of wine is seen as the golden standard of wine: it can be stored for up to a century, depending on the closure and the wine style, and the wine in it may continue to develop desirable flavour compounds.

[0011] Once a standard size bottle is opened, the wine in it starts to deteriorate. Oneway of reducing such deterioration is to inject argon, an inert gas, to replace air in the headspace of the bottle has been commercialised under the Trade Mark CORAVIN.

[0012] Consumers who are aiming to drink alcohol in a more mindful and healthy fashion are expressing commercial preferences for smaller containers that do not encourage excess consumption, i.e. which are designed to be opened and the content drunk. Since the effect of oxygen leakage for exam pie via the cork, is more pronounced the less wine is in the container, this is problematic. However, a move to smaller containers also presents a significant barrier to consumers who wish to try new wines. The industry has tried for at least 30 years to explore small containers, without much change in the availability of a wide range of wines, even in so- called “half bottles”.

[0013] US patent specification 10759553 discloses a method of repackaging wine into small PET bottles which focuses on the use of inert gas chambers to reduce contact with atmospheric oxygen during the repackaging process, but this does not solve the challenges of microbial spoilage, which is a far more significant factor than oxygen exposure for many wine styles.

[0014] In terms of the microbial spoilage pathway, wines can go off by a number of different means. Acetobacter can react with ethanol to create ethanoic acid and ultimately turn the wine into vinegar. Lactic bacteria can operate on lactic or citric acid in the wine. Yeast can operate on sugars in the wine to cause secondary fermentation and many others can cause the wine to spoil.

[0015] Standard practice in the wine industry is to clean and sterilise the bottle before it is filled, and to filter the wine, removing any microorganisms present before it is bottled.

[0016] For smaller containers, though, this is very challenging. When combined with the oxygen challenge, no small (<500ml) container has been proven capable of reliably packaging many styles of wine without spoilage or rapid ageing. Often, the wine can deteriorate badly in just two weeks at room temperature, to the point where it is no longer drinkable, and certainly does not match the taste and bouquet of a freshly poured serving from a traditional 750ml glass bottle. Small portions of wine in particular are less stable than larger containers, owing to a higher ratio of surface area to volume, with many potential contaminants resting on the internal surface of the container prior to filling thus increasing the concentration of contaminants per unit volume.

[0017] Many wines make use of sub-micron filtration to reduce microbial activity, but this relies on being run through a perfectly-sterile packaging process into a perfectly-sterile container, which is not always the case.

[0018] Filtration is also associated with stripping flavourand texture from the wine and is not favoured by many winemakers.

[0019] Other wines add chemical preservatives, including but not limited to potassium metabisulphite, dimethyl dicarbonate or potassium sorbate to provide microbial stability, but consumers are increasingly opposed to use of chemical preservatives, and these affect the flavour, can cause allergic reactions and are not all suited to all potential microbial contaminants.

[0020] Packaging small quantities of beverages in flexible packaging involves more pronounced challenges than using small glass bottles. A common technique to destroy microorganisms in the beverage in question is pasteurisation through application of high heat, which is not suitable for flexible packaging, nor for delicate substances in the wine which are negatively affected by heat. Pasteurisation can be used for cider or sangria or even table wines, but are inappropriate for many wines where the consumer chooses on the basis of their flavour. Flexible packaging however cost little and has a small environmental footprint

[0021] Even if the wine is filtered before being filled into a flexible package, for example the bag in a wine box, this often does not prevent deterioration as the flexible package may not be perfectly sterile prior to filling (unlike a glass bottle which can be sterilised with heat treatment) so allowing the ingress of microorganisms into the final sealed product, either from the atmosphere in the packaging machine, or from the surface of the flexible packaging material.

[0022] Another type of container is the can, but this has disadvantages. Cans do not permit enough oxygen to enter the wine, resulting in several chemical reactions suffering from insufficient oxygen to carry out their usual process. An example of this is the polymerisation of tannins, a group of phenolic compounds which bind together over time, with a small amount of oxygen, smoothing out the wine and creating a more pleasant flavourand feeling in the mouth. Cans have proven inadequate for many styles of red wine because of this. Likewise, there have been challenges with the passivation layer conventionally applied to the interior surface of the can suffering from fractures, allowing a galvanic reaction that creates hydrogen sulphide, smelling of rotten eggs. Finally, as a non-sterile filling process, many wines are not suitable and refermentation has been seen to destroy can packaged wines in as little as two weeks.

[0023] Finally, in recent years there has been an attempt at commercial activity involving repackaging small portions of wine in glass tubes. This requires all wines to be submitted to a laboratory analysis to estimate their suitability for such repackaging. The view by many is that nonalcoholic or low alcohol content wines are not suitable because of the potential for microbial spoilage. Attempts to reduce this through addition of further chemical preservatives changes the flavour and aroma characteristics of the product, rendering it inappropriate for most if not all wines.

[0024] Since the 1990s it has been known that the application of a high pressure differential to a food product such as jam as part of the manufacturing process can markedly increase the stability of the end product.

[0025] JP published specification 1994217758 discloses a method of increasing protection against spoilage by Niochi bacteria - a key cause of damage to a rice-based product - by filling a sealable plastics foil bag with the rice wine, placing it in a tank of water, and subjecting the tank content to a pressure of between 100 and 600 MPa, preferably at least 300 MPa. The temperature of the water in the tank may be greater than ambient, e.g. up to 50 degrees centigrade, in order to reduce the bacterial and enzyme inactivation times, but even at that temperature, processing time can be reduced to 10 minutes, compared with 30 minutes needed at 25 degrees centigrade.

[0026] Limited experimentation has been carried out on the use of high pressure on wine in plastic kegs to reduce the amount of preservatives required for long-distance shipping. Limited experimentation has also been carried out on the effect of a pressure differential on the organoleptic properties of wine.

[0027] US published specification 2020 / 0369993 discloses the application of high-pressure treatment to beverages, particularly natural beverages, packed into food grade plastics bottles, for example of PET, for 1 to 5 minutes, at ambient temperature, and at a pressure of 70000 to 95000 psi (485 to 655 MPa).

[0028] We have now found that the problem of producing single-serve wine packages with long shelf lives and without material deterioration of the quality of the wine in question can be solved by the use of a method of processing comprising a number of steps and using a combination of materials and process conditions, the latter including encapsulating a single-serve quantity of wine into a sealed pouch or sachet and subjecting it to the application of very high hydraulic pressure conditions.

[0029] Summary of the invention

[0030] According to the present invention there is provided a method of making a long shelf-life package containing wine which comprises the following sequence of steps: a) encapsulating single-serve amounts of the wine into a series of flexible-walled containers, preferably pouches or sachets made of a multilayer plastics film or foil, and sealing the amount therein substantially to fill each container b) placing the filled containers into a holding container c) immersing the holding container into a pressure vessel d) increasing the pressure in the pressure vessel , preferably to at least 10OM Pa, and least for a time period sufficient essentially to deactivate any microorganisms within each filled container, and e) packaging the containers in any secondary packaging required for presentation or shipping .

[0031] As a preliminary step, it may be convenient to start the method by transferring the wine into a large capacity holding vessel under conditions of little or no oxygen contact.

[0032] Step a) may be carried out by using a continuous operation filling machine of a type used in the food processing industry, and which is designed to produce, usually under inert atmospheric conditions, a sequence of sealed packages of in the form of liquid- or paste-filled pouches or sachets. Such a filling machine may include means for separating the sealed packages into units and applying markings to each.

[0033] One of the major advantages of this process is that it can all be carried out at ambient temperature, so changes in the wine composition which often occur with sterilisation using heat are entirely avoided.

[0034] While theoretically the wine to be processed may be freshly made, the particular advantages of the inventive process are that it can be applied to wine which has been made some time in the past, stored in bottles for months or years, and then decanted from the bottles and processed to provide the single serving which reflects and maintains the qualities of the bottled and matured wine from which it came. Using the method of the present invention it is possible to undertake commercial-scale high volume production of small, single-serve wine-containing products which can be packed in simple card or like containers which can be distributed as samples. We have found surprisingly that the treatment of the wine according to the method steps just identified enables singleserve packages in which the wine, after storage for six or more months, is indistinguishable from the taste and bouquet of the wine which has not undergone the method but simply been allowed to mature in (usually) bottles.

[0035] The use of high differential pressure leads to a dramatic advance in the shelf life of all wines in small portions. More than 350 different styles of wine have been tested successfully, including those which lasted just weeks at ambient temperature if simply filled into singleserving size containers.

[0036] The method of the invention employs a high differential pressure process for reducing the level of active microorganisms in commercial single-serve wine portions.

[0037] The method thus provides an alternative mechanism for sterilising the final packaged product. Because high differential pressure can be applied to a closed, complete flexible package containing wine, the contents are not subjected to any post-processing contamination with spoiling or pathogenic microorganisms, resulting in a considerably longer shelf life than products which are heat-treated or filtered, then subsequently packaged.

[0038] The high differential pressure processing acts to inactivate any spoiling or pathogenic microorganisms that have entered the product, with at least a 4 Iog10 to 5 Iog10 reduction in active cell count. The organoleptic flavour and aroma qualities of the final product are not affected by the process, maintaining the desirable fresh qualities.

[0039] A major advantage of the process according to the invention is that it protects the wine against one of the main spoilage mechanisms which cause wine to become poorer in quality or indeed undrinkable, viz. the refermentation of the sugar by yeast. The high differential pressure processing has the advantage that it solves other yeast, mould and bacteria-induced problems as well.

[0040] While considerable experimental data has been gathered on food processing through the application of high differential pressure to kill microorganisms, even at room temperature, there are considerable engineering challenges to generating and containing the extreme pressures, and in ensuring a flexible package can survive the process without damage occurring, before it can reach a reliable, repeatable commercial process. It has been surprisingly found that the contact with oxygen during the packaging process does not cause a chain reaction in the wine that leads to its spoilage, as is described in much scientific literature in this area, but that even a small level of microbial contamination causes a far more significant challenge for wines under 15% alcohol by volume, above which the activity of many microorganisms is reduced by the level of alcohol.

[0041] Through use of the invention, care about oxygen contact during repacking can be greatly reduced as the wine is far more resistant against oxygen damage than previously thought. The difference can be explained by the fact that microbial growth will also reduce the levels of preservatives in the wine, leading to further oxygen contact reacting with the wine, not the antioxidant preservatives.

[0042] Preferably the maximum hydrostatic pressure differential applied would be around 600 MPa.

[0043] Best results have been achieved when the pressure differential is held for between 30 and 120 seconds, preferably between 45 and 90 seconds.

[0044] What has been especially surprising is the effect on wines with lower alcohol levels, higher levels of residual sugar and volatile chemicals, or lower levels of free SO2 preservatives. In these wines, the maintenance of the taste of the bottled wine once processed and treated in accordance with the invention to provide a single serve package is remarkable and dramatic and is key to creating a small portion of these products. In particular, none of the prior art is capable of producing samples of these low alcohol wines.

[0045] The particular advantage of achieving these levels of pathogen inactivation with such relatively short cycle times and without any changes to the flavour is that the overall throughput of the process can be fully-commercial at scale, while also presenting the product as it would be if it had just been poured from a freshly opened traditional glass bottle.

[0046] Packages of commercial wine products produced according to the method described above have been shown to have a shelf life of greater than 365 days at ambient temperatures between 5 and 25 degrees Celsius.

[0047] Through high differential pressure processing, the membranes of the microorganisms, which are at ambient pressure, are exposed to significant stresses, causing them to rupture, rendering it inactive. Carried out in a pressure vessel, this can be applied simply by subjecting the interior of the vessel to high pressure. The vessel may be filled with liquid or simply ambient atmosphere

[0048] The time that the wine container is placed under this level of pressure must be consistent with commercial production process requirements and result in elimination or inactivation of a sufficient proportion of the target microorganisms while maintaining the quality and flavour of the wine.

[0049] The preferred multilayer flexible foil or film used when practicing the invention relies on a strong flexible layer laminated to an oxygen barrier layer in order to protect it during the application of a high differential pressure. One layer may be of nylon to provide resistance to delamination and puncture. A preferred example is a four-layer laminate of PET / nylon / aluminium / polyethylene, where the polyethylene layer is on the inside of the pouch or sachet, in contact with the wine.

[0050] The method according to the invention is of particular value in enabling sample packs to be assembled containing, for example, 6 different wines. By the used of card cartons for each sachet and a cardboard outer box fitted to the 6 assembled packages, an overall packaged product may be produced with a very low environmental footprint.

[0051] Further details of how the invention may be put into practice are described in a non-limiting fashion in the following two examples. The first example describes an initial attempt to carry out the method of the invention. Example 2 describes the successful use of the method.

[0052] Example 1

[0053] The following test conditions were applied to 12 different wines, covering a range of styles including dealcoholised, natural (without preservatives), low alcohol, aromatic, rich, full-bodied and delicate, including red, white and rose wines.

[0054] First, a stainless steel tank in an ISO class 7 clean room was sterilised with steam and filled with CO2. The wines were then decanted from 750ml bottles into the tank.

[0055] 50 pouches of laminate aluminium / PE film were formed and cleared of oxygen and the wine was measured into 100ml portions and transferred into the pouches, which were closed and marked with a batch code and filling date. Half of the pouches were then subjected to a differential pressure treatment and the other half kept as control samples.

[0056] The pouches were opened and the contents tested at periods of one month, three months and six months after filling.

[0057] The extremities of the pressure process caused significant damage to several of the pouches, with leaks and delamination occurring. In particular, the oxygen barrier was damaged in many pouches, with the aluminium peeling away from the inner layer of polyethylene (PE).

[0058] This provided three groups to analyse:

[0059] 1) Control group. Oxygen and microbial exposure during packing, but good oxygen seal so little oxygen contact after sealing.

[0060] 2) Treated but damaged. Oxygen and microbial exposure during packing. Microbes potentially killed by pressure, but oxygen transfer allowed by damaged aluminium layer.

[0061] 3) Treated. Oxygenand microbial exposure during packing. Microbes potentially killed by pressure. Little oxygen contact after sealing.

[0062] This approach enabled determination of the effectsofthe oxygen on its own and the microbes.

[0063] At two weeks, the untreated dealcoholised wines were refermenting, as evidenced by the pouches inflating through CO2 produced by yeast turning the sugar into alcohol and other microbial damage. The same wines treated with the differential pressure did not suffer the same problem. The untreated samples had to be removed before they exploded through excess pressure.

[0064] After one month, the first taste tastes and laboratory analyses were performed. Unexpectedly, the count of active microorganisms remained low. However, the difference between the treated and untreated was dramatic. The untreated low SO2 wines had turned rancid, as had several others. The treated ones remained fine.

[0065] On the wines with damaged oxygen barriers, the first signs of classic oxidation had emerged, with aromas of baked apple appearing, indicating the transformation of alcohol into aldehydes.

[0066] Of the control group (1), the higher alcohol wines remained in acceptable condition, with a hint of mustiness. However, the lighter wines were in a very poor condition, and many were rancid. All of group (2) were destroyed after 6 months, confirming that the transfer of oxygen into the sealed container was still very important. However, the spoilage mechanism was very different to the control group - wines were overdeveloped, with oxidative flavours rather than rancid.

[0067] After six months, all of the treated, undamaged wine samples from group (3) remained in perfect condition, compared to freshly -opened 750ml bottles of wine which had been stored at ambient temperature together with the group (3) samples. This is consistent with a conclusion that during the packaging process oxygen contact was largely irrelevant and that the approach used demonstrated that a packaging process as described was capable of producing single-serve wine packages in which the wine was kept perfectly for at least 6 months at ambient temperature. The results are set out in the following table:

[0068] Example 2

[0069] The test from example 1 was repeated on 24 different wines but using as the flexible laminate film one comprising a layer of nylon in addition to the layers of aluminium and PE in order to protect it against the stresses endured during the pressure application.

[0070] 100% of the wine samples tested remained in perfect condition for 12 months after storage at room temperature, even low alcohol, high sugar wines which present the most challenging case. The test was judged by the Master of Wine who oversaw production of all 24 wines. The results are set out in the following table:

[0071]

[0072] Subsequent tests on more than 350 different wines have been tested in the new material and there has been a zero failure rate, even on de-alcohol ised wines, after 12 full months or longer. Some of these fragile wines were tested in parallel with 100ml glass bottles at the same time. Many of these glass-bottled samples lasted less than 3 weeks before undergoing major deterioration.

Claims

CLAIMS1. A method of making a long shelf-life package containing wine which comprises the following sequence of steps: a) encapsulating single-serve amounts of the wine into a series of flexible-walled containers, and sealing the amount therein substantially to fill each container b) placing the filled containers into a holding container c) placing the holding container into a pressure vessel d) increasing the pressure differential in the pressure vessel for a time period sufficient essentially to deactivate any microorganisms within each filled container, and e) removing the filled containers from the holding container, and packaging them.

2. A method according to claim 1 wherein the flexible-walled containers are pouches or sachets made of a multilayer plastics film or foil.

3. A method according to claim 2 wherein in step a) the flexible-walled containers are produced by a continuous operation filling machine which produces a sequence of sealed packages of wine.

4. A method according to claim 3 wherein the filling machine includes means for separating the sealed packages into units and applying markings to each.

5. A method according to any one of claims 1 to 4 wherein in step d) water is added and the pressure is increased to at least 100 MPa.

6. A method according to any one of claims 1 to 4 wherein in step d) water is added and the pressure is increased to a maximum value between 100 and 600 MPa.

7. A method according to any one of claims 1 to 6 wherein in step d) the pressure is applied for a time period of 30 to 240 seconds.

8. A method according to any one of claims 1 to 6 wherein in step d) the pressure is applied for 45 to 90 seconds.

Images