CARBONATED MILK

Abstract: An aerated or carbonated milk product drink comprising a milk product which has been carbonated with a gas or mixture of gases under pressure and packaged into a container. The milk product may be any natural or artificial milk product including dairy products and non-dairy milk products and includes combinations of milk products with other beverages such as fruit juices. The method of producing the carbonated milk product of the present invention comprises injecting under pressure carbon dioxide gas or a mixture of gases into the milk product at low temperature of less than 10 DEG C and high pressure of from 50 kpa to 200 kpa. The carbonated milk product remains carbonated in the package until opened for a reasonable shelf life.

Description: CARBONATED MILK The present invention generally relates to food substances, and in particular to beverages. More particularly, the present invention relates to milk drinks which have been carbonated or aerated. Preferred embodiments of the present invention include an ultra heat treated sparkling skim milk drink including combinations of all milk and all" flavours of milk, all fruit juice combinations, fermented yoghurts, non-diary products e.g. soya, field milk, artificial milk and the like. In addition, the present invention relates to a method of carbonating milk and packaging the carbonated milk in aseptic and non-aseptic packaging. Although the present invention will be described with particular reference to an ultra heat treated pasteurization, (HTST) and chemical pasteurization milk drink aerated with sterilized and purified carbon dioxide and to methods of carbonating the treated milk it is to be noted that the present invention is not necessarily limited to this embodiment and the scope of the invention may be more extensive by including within it other beverages aerated with other gases and gas mixtures of varying ratios, such as substitute milk products, for example soya substitutes. It is to be noted that the use of the general term milk products includes all kinds of milk products whether natural or artificial, milk or substitute milk materials, such as for example, whole milk, low- fat milk, modified milk, yoghurt and milk products in general including combinations with other beverage materials such as fruit juices, soy and the like. Soft drink sales and sales of aerated and/or carbonated beverages in general have over a period of time increased so that not only are more beverages in general being sold but the market share of soft drinks and other carbonated drinks have been increasing at the expense of other types of drinks, such as milk product drinks. In order to increase the appeal of milk as a drink and hopefully to gain an increased market share for milk drinks, particularly in situations away from a refrigerator such as during out-of-home activities, it has been thought that if carbonated and/or aerated milk was available this product, because of its similarities to soft drink in appeal, would be successful in view of it being perceived as a more healthy alternative to soft drinks. Additionally, at present in many countries there is an oversupply of milk and large surpluses of milk and milk products are in existence. Carbonated milk could at least alleviate these large surpluses of milk and milk products. Therefore, the present invention is an attempt to redress both problems mentioned above, (i) to gain a greater market share for milk drinks and (ii) to reduce the amount of surplus milk or milk products. Technically, there are some inherent problems which must be overcome in order to be able to carbonate milk and to package the carbonated milk in aseptic packages while carbonated. Among these problems include the following two technical problems which are (a) the nature and behaviour of the product stored under aseptic refrigeration during the manufacture before packaging requires that a settling step be introduced in the manufacture to allow the carbonated product to have the required desired properties when packaged, and (b) the excessive foaming caused by sparging with gases at lightly elevated temperatures which may require the use of anti-foam additives. Moreover, there is the general problem of the stability of milk emulsion during processing and subsequent packaging and storage which makes the carbonation of milk difficult. Therefore, it is an aim of the present invention to provide a method for carbonating milk products and combinations of milk products and to provide a carbonated milk product. According to the present invention there is provided an aerated beverage comprising a milk product in general which is aerated or carbonated with a suitable gas or mixture of gases in a suitable package whereby the milk product remains carbonated in the package for a reasonably long shelf life until opened. According to a further aspect of the present invention there is provided a method of aerating or carbonating a milk product comprising introducing a gas or a mixture of gases into a milk product under pressure, maintaining the milk product in an aerated or carbonated state and packaging the aerated or carbonated milk product into a package. Typically, the milk product includes whole milk, skim milk, low fat milk, total milk solids, non-fat soy or any other product conventionally referred to as a milk or dairy product or non-dairy product or artificial milk product or milk substitute product where solid or liquid of any viscosity. Typically, the package includes bottles, cartons of paperboard or any suitable materials, softpacks of suitable plastic materials, bottles of plastics including PET, polypropylene and mixtures thereof or the like. The present invention will now be described by way of example with reference to the accompanying drawings in which Figure 1 is a flow chart illustrating one embodiment of the overall method and apparatus of one form of making the product of the present invention by one method. Example 1: An ultra heat treated sparkling skim milk ' drink. (a) Skim Milk Product which typically contains the following ingredients in the following ranges: (b) A batch of fresh whole milk is pumped from a suitable source into stainless steel holding tank 2 where its pH is adjusted to a desired level in accordance 10 with a preselected product taste usually in the range from 3.8 to 6.9 and cooled to a temperature of about 5°C where it is maintained for a suitable period until required. The milk sample is then pumped to heat exchanger 4 where it is heated to a temperature of about 15 40°C. However other temperatures may be obtained. It is preferable that indirect heat is used to. raise the temperature, such as for example by using a plate heat exchanger. The heated whole milk is then separated in a separator 6 to produce a first portion which is 20 substantially skim milk and a second portion which is essentially cream having a fat content of about 40%. The second portion is pumped to a refrigerated stainless steel holding tank 8 where it is stored until required for further use. The first portion of skim milk is 5 standardized to about 1%' + .5%, as required, 0 - 5%, is then pasteurized at about 72°C. After maintaining the skim milk at 72 C for the required time, such as for example for 15 seconds or other corresponding time in accordance with the approved heat holding time method, 0 the skim milk is cooled to about 2 - 10°C, preferably 4°C, and ' the pH is adjusted to the preselected value which is between 3.8 and 6.9 as required by adding citric acid monohydrate CgHgO H-O and citric acid C g Hg0 7 and stored in a refrigerated stainless steel vat, mix tank or similar 10 for use as required- When required the skim milk is passed to refrigerated stainless steel mix tank 12 where additives may be added in predetermined amounts. Examples of such additives include flavours, colours, sweeteners and the like including any food grade material. In one embodiment an alcoholic additive may be used such as for example a whiskey-base flavouring. Thus, by this process there is produced a skim milk product, optionally containing any suitable or desirable additives, suitable for subsequent processing into a drink in accordance with the present invention. Typically, the mixture thus produced is held at this temperature for approximately up to 1 hour, preferably 30 minutes for protein protection maturity= (b) Ultra heat treatment The skim milk sample, optionally containing any suitable, conventional or desirable additives, is pumped from the stainless steel mix tank 12 to a ultra heat treatment (UHT) plant 14 where in the first stage which is the UHT preheater being a plate heat exchange 16, the skim milk is indirectly heated from a temperature of from 4°C to a temperature of about 138 C. After attaining a temperature of 138°C the milk is ultra heated from 138°C to 150°C in the UHT heater 18 where it is held at a pressure of 700 kPA or an appropriate pressure for about 2.25 seconds within limits as required to kill microorganisms, pathogens, bacteria and the like. It is to be noted the precise conditions can change such as at a temperature of 153 for 2.5 seconds or similar. Thereupon it is cooled, preferably to below 10 C, more - 1 - preferably to 2°C immediately. Thus, at this stage in the regeneration part 20 of the UHT plant 14, there is now provided a ultra heated skim milk product. (c) Product carbonating The ultra heated skim milk product may be carbonated in the following ways-by direct injection of sterilized, purified carbon dioxide gas into the coding chamber section of the plate heat exchange to the stainless steel holding receptacles, refrigerated in aseptic-modified pressurised maturing tanks. One form of the carbonator is substantially integral with the UHT and is denoted generally as 22. Another form of the carbonator may be located remote from the UHT plant 14. In the embodiment illustrated the carbonator 22 is integral with the UHT plant or nearly so. Briefly, carbonator 22, which may be especially designed or modified for the present plant or may be a conventional carbonator either as is or modified as required comprises a carbon dioxide inlet for receiving carbon dioxide or a mixture of gases, a filter and an injection nozzle (atomizer). Typically, the supply of carbon dioxide is from 11 to 56 kg per hour and is typically delivered under pressure range of from 50 kPA to 200 kPA. The carbon dioxide then passes through a filter sterilizer to ensure that the carbon dioxide which is used to carbonate the skim milk is pure, sterilized and aseptic. Typically, the carbon dioxide undergoes gas filtration and sterilization to produce a substantially purified carbon dioxide. After passing through the filter the carbon dioxide is passed to a carbon dioxide injector for actually injecting gaseous carbon dioxide into the skim milk. Typically, the injector is an adjustable or otherwise controllable carbon dioxide injector used in the beer-brewing and bottling industry or a modified sparger. One form of the injector is supplied by Holstein V. Koppert GmbH of West Germany. Briefly, this injector has an adjustable needle-like valve which controls the size of opening of a port which is located in a tube perpendicular to the direction of flow of the milk inside the tube. Typically, the amount of carbonation is about 3 vols./8 vols. and the -carbon dioxide is supplied at a pressure of 60 p.s.i. to the milk. The injection of the carbon dioxide takes place by sparging the milk product. An inlet for the carbonator is provided to admit the milk product thereto from the remainder of the UHT plant. A further inlet in the form of a conduit is provided for admitting carbon dioxide under pressure into the carbonator for atomisation. Another example is a sparge pipe provided with an injector for dispersion. In one embodiment the milk product is passed through the i jector. Once the skim milk has been carbonated at 2 C + 1°C it is pumped to a pressurised carbonator holding tank 30 where the carbonated product is held under pressure in order to maintain its carbonation to fully mature and saturate. Typically, the carbonator holding tank is maintained at a pressure of 450 kPA and a temperature of 2 to 6°C. Holding tank 30 is provided with a carbon dioxide sensor probe for measuring the amount of the carbonation of the milk product. One form of the carbon dioxide sensor is that provided by Canongate Technology Limited of Scotland under the name "EMBRA" carbo-check gas monitor. In another embodiment carbon dioxide from the carbonator is used to carbonate the milk product in line in a manner similar to that described using an injector but with the difference that in this case it is in-line sparger. In this embodiment the carbon dioxide is delivered-at a pressure which is compatible with the filling operations, typically of about 450 kPA. The carbon dioxide is cooled to about 0.2°C or thereabouts and is filtered by two Sterile Micron Filters, typically each being a 3-stage filter arrangement. The amount, quality and other characteristics of the carbon dioxide is maintained by an 'in-line' gas analyser set-up for carbon dioxide, such as for example, the "Embra" gas monitor and/or analyzer. Control of the distribution of carbon dioxide to the in-line type modified sparger for milk is by means of a carbon dioxide Control Panel which controls the amount of carbon dioxide being delivered to various locations for carbonating the milk product. Conventional gas control means are employed. In the event that the amount of the carbon dioxide levels or the amount of carbonation of the milk product is insufficient, suitable sensors connected to the gas analyser detect this condition so that by means of the control panel the insufficiently carbonated product can be diverted to be reprocessed through the carbonator in a return loop to a holding tank to be repasteurized to be within the specification. (d) Packaging After the milk is carbonated by the process described above either using a carbonator more or less integral with the UHT plant, a separate carbonator or an in-line sparging pipe, it is conveyed to an aseptic pressure balanced.tank which is specifically designed to settle/pacify the milk. It is then conveyed to the packaging station 40 where the carbonated milk product is packaged into sterile containers. Prior to packaging the milk, suitable containers such as for example cans or bottles, are sterilised by dry heat such as for example using hot blasts of air heated to a temperature of 150°C directed onto the cans or bottles for about 58 seconds or a chemical (cooled refrigerated) twist rinse sterilising bath suitable for bottles, including plastic bottles using ultra violet sterilization. The bottles or cans may additionally be sterilised by the injection of nitrogen. The milk product is maintained at a suitable pH depending on the product, during the packaging operations. Just prior to filling, the sterilised containers are purged with sterilised purified carbon dioxide and/or nitrogen. Typically, the packages into which the carbonated milk is packed are bottles, cans, plastic containers, either rigid or flexible. Additionally, the caps, tops, lids, closure means or the like are either separately or simultaneously sterilized by any suitable or convenient method. After packaging the milk product into individual containers the milk may be further sterilized by non-toxic radiation or pasteurizationation. The filling operations is by means of a modified counter pressure aseptic filler conveniently housed in a clean environment, i.e. forced air pressure in super atmospheric clean surroundings. The finished packages are then pressure checked, product coded, boxed into cartons and the cartons stacked onto pellets for storage in refrigerated or chilled conditions. It is anticipated that the shelf life will be about 6 ' eeks. However, in UHT situations coupled with 100% aseptic filling the shelf life will be greatly extended. Under refrigeration the containers have an extended shelf life. The described arrangement has been advanced by explanation and many modifications may be made without departing- rom the spirit and scope of the invention which includes every novel feature and novel combination of features hereindisclosed. Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is understood that the invention includes all such variations and modifications which fall within its spirit and scope.

Claims: THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A method of aerating or carbonating a milk product comprising introducing a gas or a mixture of gases under pressure into a milk product, maintaining the milk product in an aerated or carbonated state and packaging the aerated or carbonated milk product into a package. 2. A method according to Claim 1, in which the milk product is whole milk, skim milk, low fat milk, total milk solids, modified milk, non-fat soy or any other milk product either essentially natural or essentially artificial. 3. A method of according to Claim 2 in which the skin milk product has the following formulation: 4. A method according to Claim 1, in which the milk product is a skim milk comprising standardising the skim milk to about 0 to 5% fat content, preferably 0.5 to 1.5% fat content. 5. A method according to Claim 4 in which the skin milk is heated to at least 70°C and maintained at that ** temperature and then cooled to about 2 to 10°C whereupon the pH is adjusted to a range between 3.8 and 6.9. 6. A method according to Claim 5 in which the milk product is ultra heat treated in an ultra treatment apparatus. 7. A method according to Claim 6 in which the ultra heat treated milk product is carbonated by a carbonator comprising a direct injection of sterilized, purified carbon dioxide gas or gas mixture. 8. A method according to Claim 7 in which the carbonator is substantially integral with the ultra heat treatment apparatus. 9. A method according to Claim 7 in which the supply of carbon dioxide from the carbonator is from 11 to 56 kg per hour at a pressure in the range from 50 kPA to 200 kPA. 10. A method according to Claim 9 in which the injector of the carbonator has an adjustable needle-like valve. 11. A method according to claim 10 in which the carbonator has an injection tube part of which is located in a tube for injecting carbon dioxide perpendicularly to the direction of flow of the milk in the tube. 12. A method according to Claim 11 in which the amount of carbonation is in the range of from about 3 vols. to 8 vols. 13.- A method according to Claim 7 in which the carbonation takes place at about 0 to 5°C preferably 2°C to 1°C. 14. A method according to Claim 13 in which the carbonated milk product is maintained under pressure in a pressurised carbonator holding tank or settling tank in * order to facilitate the carbonated milk product to mature and saturate. 15. A method according to Claim 14 in which the holding'or settling tank is maintained at a pressure of 450 kPA and a temperature of from 2 to 6°C. 16. A method according to Claim 7 in which the carbonated milk product is packaged into sterile containers. 17. An aerated or carbonated beverage comprising a milk product aerated or carbonated with a gas or gas mixture in a suitable package made in accordance with the method of any one of Claims 1 to-16, whereby the milk product remains carbonated in the package.

Inventors: TRACEY MICHAEL ALOYSIUS, TRACEY, MICHAEL, ALOYSIUS
Applicants: TRACEY MICHAEL ALOYSIUS, TRACEY, MICHAEL, ALOYSIUS
Application year: 1988
Main classification: A23C9
IPC codes: A23C3, A23C9