Abstract:
An aerated or carbonated milk product drink comprising a shelf stable pre-heated and pressurized ultra-heat treated milk product which has been carbonated with a gas or gases under pressure and packaged into a container. The milk product may be 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 shelf-stable 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 degrees centigrade and high pressure of from 50 kpa to 200 kpa. The carbonated milk product remains carbonated and shelf stable in the package until opened.

Description:
BACKGROUND  
         [0001]    1. Field of Invention  
           [0002]    The present invention generally relates to food substances, and in particular to beverages. More particularly, the present invention relates to ultra heat treated (UHT) milk drinks which have been carbonated or aerated. Preferred embodiments of the present invention include an ultra heat treated, (UHT) sparkling skim milk including combinations of all ultra heat treated, (UHT) milk and all flavors of ultra heat treated, (UHT) milk, all ultra heat treated, (UHT) fruit juice combinations, ultra heat treated, (UHT) fermented yogurts, ultra heat treated, (UHT) non-dairy products, e.g.: soya, field milk, artificial milk and the like. In addition, the present invention relates to a method of carbonating ultra heat treated, (UHT) milk in aseptic and non-aseptic packaging.  
           [0003]    Although the present invention will be described with particular reference to an ultra heat treated, (UHT) 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.  
           [0004]    It is to be noted that the use of the general term, ultra heat treated (UHT) milk products include all kinds of ultra heat treated (UHT) milk products whether natural or artificial, milk or substitute milk materials, such as for example, whole milk, low fat milk, modified milk, yogurt, and milk products in general including combinations with other beverages such as fruit juices, soy and the like.  
           [0005]    2. Discussion of Prior Art  
           [0006]    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 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.  
           [0007]    The use of ultra heat treated (UHT) milk is well established in the art. It is well known that preheating milk to a temperature of 80 degrees centigrade then heating the preheated milk intensively for a short period of time, i.e. for approximately 2-5 seconds, to approximately 130 degrees-150 degrees centigrade followed by instant cooling to a temperature below 80 degrees-90 degrees centigrade will allow milk to become shelf stable. This heat sterilization process which also uses pressure during the ultra heat process kills micro organisms and allows one to keep milk shelf stable without refrigeration. Typical ultra heat treated (UHT) milk formulation processes are set forth in the U.S. Pat. No. 3,973,048 to Tetra Pak Development SA (1976), U.S. Pat. No. 6,165,532 to Parmalat S.p.A. (2000) and in U.S. Pat. No. 4,921,717 to Milk Marketing Board (1990).  
           [0008]    Unfortunately, these patents do not relate to the process of carbonating or aerating the ultra heat treated (UHT) milk.  
           [0009]    It is to be noted that the carbonation of milk is also well established in the art. Typical milk carbonation formulas are set forth in U.S. Pat. No. 607,362 to F W H Graeff (1898), in U.S. Pat. No. 1,570,975 to D. Sweeney (1926), in U.S. Pat. No. 2,394,303 to H. Griesbeck (1940), in U.S. Pat. No. 4,804,552 to Dairy Research (1989) and U.S. Pat. No. 4,919,960 to Dairy Research (1990).  
           [0010]    Unfortunately these patents to do not relate to carbonating ultra heat treated milk products using a pre-heat and pressure process. In addition, these patents relate to the need of refrigerating the finished milk product and are not shelf stable.  
           [0011]    Thus, a need exists for a carbonated or aerated ultra heat treated (UHT) milk beverage which uses a pre-heat/pressure process and does not need refrigeration for the finished product and is shelf stable.  
         OBJECTS AND ADVANTAGES  
         [0012]    Accordingly, several objects and advantages of my invention are:  
           [0013]    (A) to provide a method for carbonation of pre-heated and pressurized ultra heat treated (UHT) milk products and combinations of pre-heated and pressurized ultra heat treated (UHT) milk products and to provide a pre-heated and pressurized ultra heat treated (UHT) carbonated milk product that may also be flavored.  
           [0014]    (B) to provide a method to aerate of carbonate pre-heated pressurized ultra heat treated (UHT) milk with suitable gas or mixture of gases in a suitable package whereby the pre-heated and pressurized ultra heat treated (UHT) milk product remains carbonated in the package for a reasonably long shelf life until opened and no refrigeration is required.  
           [0015]    (C) to provide a method of aerating or carbonating pre-heated and pressurized ultra heat treated (UHT) milk comprising of introducing a gas or a mixture of gases such as carbon dioxide into an pre-heated and pressurized ultra heat treated (UHT) milk product under pressure, maintaining the pre-heated and pressurized ultra heat treated (UHT) milk product in an aerated or carbonated state and packaging the aerated or carbonated pre-heated and pressurized ultra heat treated (UHT) milk product into a package Typically, the package includes bottles, aluminum cans, cartons of paperboard, aseptic or non aseptic packaging, plastics including PET, polypropylene and mixtures thereof or the like.  
           [0016]    (D) to provide a method of aerating or carbonating pre-heated and pressurized ultra heat treated (UHT) milk to include whole milk, low fat milk, total milk solids, non-fat milk, soy or any other product conventionally referred to as milk or dairy product or non-dairy product or artificial milk product or milk substitute product where solid or liquid of any viscosity.  
           [0017]    (E) to provide a method of carbonating pre-heated and pressurized ultra heat treated (UHT) milk without the excessive foaming and destabilization caused by sparging with gases at lightly elevated temperatures.  
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    In the present invention, the foregoing difficulties are obviated in that there is provided a method to carbonate or aerate pre-heated and pressurized ultra heat treated (UHT) milk. In a preferred embodiment the carbonated or aerated pre-heated ultra heat treated (UHT) milk is flavored and packaged in sterile bottles, cans or aseptic packaging.  
         [0019]    In accordance with the invention, the un-carbonated milk can be processed into pre-heated and pressurized ultra heat treated (UHT) milk in the usual well known method in the art. To carbonate and package, the following formulations can be utilized:  
       EXAMPLE 1  
       [0020]    A. (Ultra Heat Treatment)  
         [0021]    The milk sample, optionally containing any suitable, conventional or desirable additives is pumped from a stainless steel mix tank to an ultra heat treatment (UHT) plant where in the first stage which is the UHT pre-heater being a plate heat exchange, the milk is indirectly heated from a temperature of from 4 to 8 degrees centigrade to a temperature of about 138 degrees centigrade. After attaining a temperature of 138 degrees centigrade the milk is ultra heated from 138 to 150 degrees centigrade in the UHT heater 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.  
         [0022]    It is noted the precise conditions can change such as at a temperature of 153 degrees centigrade or similar. Thereupon it is cooled, preferably to below 10 degrees centigrade, more preferably to 2 degrees centigrade immediately. At this point a flavoring agent may be introduced preferably from about 0.1% to 3% or as desired.  
         [0023]    Thus, at this stage in the regeneration part of the UHT plant, there is now provided a pre heated and pressurized ultra heat treated optionally flavored milk product which is well known in the art.  
         [0024]    B. (Milk Product Carbonating)  
         [0025]    The pre-heated and pressurized ultra heat treated (UHT) 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 pressurized maturing tanks. One form of the carbonator is substantially integral with the UHT plant. Another form of the carbonator may be located remote from the UHT plant.  
         [0026]    Briefly, the carbonator which may be especially designed or modified for the present UHT 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).  
         [0027]    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 sterilization to ensure that the carbon dioxide which is used to carbonate the pre-heated ultra heat treated 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 actual injecting gaseous carbon dioxide into the pre-heated ultra heat treated milk.  
         [0028]    Typically, the injector is an adjustable or otherwise controllable carbon dioxide used in the beer brewing or bottling industry or a modifier sparger. 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 pre-heated ultra heat treated milk. The injection of the carbon dioxide takes place by sparging the pre-heated ultra heat treated milk. An inlet for the carbonator is provided to admit the pre-heated ultra heat treated milk thereto from the remainder of the UHT plant. A further inlet in the form of a conduit is provided for admitting carbon dioxide for atomisation. Another example is a sparge pipe provided with an injector for dispersion, in one embodiment the pre-heated ultra heat treated milk product is passed through the injector.  
         [0029]    Once the pre-heated ultra heat treated milk has been carbonated at 2 degrees centigrade±1 degrees centigrade it is pumped to a pressurized carbonator holding tank 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 degrees centigrade. The holding tank is provided with a carbon dioxide sensor probe for measuring the amount of the carbonation of the pre-heated ultra heat treated milk product.  
         [0030]    In another embodiment, carbon dioxide from the carbonator is used to carbonate the pre-heated ultra heat treated 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.  
         [0031]    The carbon dioxide is cooled to about 0.2 centigrade 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 analyzer set up for carbon dioxide gas. Control of the distribution of carbon dioxide to the in line type modified sparger for pre-heated ultra heat treated 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 ultra heat treated milk product. Conventional gas control means are employed.  
         [0032]    In the event that the amount of carbon dioxide levels or the amount of the carbonation of the pre-heated ultra heat treated milk product is insufficient, suitable sensors connected to the gas analyzer 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 re-pasteurized to be within the specification.  
         [0033]    C. (Packaging)  
         [0034]    After the pre-heated ultra heat treated 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 pre-heated carbonated ultra heat treated milk. It is then conveyed to the packaging station where tie pre-heated carbonated ultra heat treated milk product is packaged into sterile containers.  
         [0035]    Prior to packing the milk, suitable containers such as for example cans or bottles, are sterilized by dry heat such as for example using hot blasts of air heated to a temperature of 150 degrees centigrade directed onto the cans or bottles for about 58 seconds or a chemical (cooled refrigerated) twist rinse sterilizing bath suitable for bottles, including plastic bottles using ultra violet sterilization. The bottles or cans may be additionally sterilized by the injection of nitrogen.  
         [0036]    The milk product is maintained at a suitable PH depending on the product, preferably 4.0 to 5.7 during the packaging operations. This suitable PH levels keep the pre-heated ultra heat treated milk from approaching or going below the isoelectric point of the milk and thus avoiding the unwanted destabilization and or foaming experienced by the prior art. Just prior to filling, the sterilized containers are purged with sterilized 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.  
         [0037]    After packaging the milk product into individual containers, the milk may be further sterilized by non-toxic radiation or pasteurization. The filling operations is by means of a modified counter pressure aseptic filler conveniently housed in a clean environment. The finished packages are then pressure checked, product coded, boxed into cartons and the cartons are warehoused accordingly.  
       CONCLUSION, RAMIFICATION AND SCOPE OF THE INVENTION  
       [0038]    Accordingly, the reader will see that a carbonated pre-heated and pressurized ultra heat treated (UHT) milk beverage of the inventor provides a solution to:  
         [0039]    aerating or carbonating a pre-heated and pressurized ultra heat treated milk product comprising introducing a carbon dioxide gas or mixture of gases under pressure into a milk product.  
         [0040]    a maintaining the pre-heated ultra heat treated milk product in an aerated or carbonated state and packaging the aerated or carbonated milk product into a shelf stable non-refrigerated package.  
         [0041]    the destabilization effect (frothing and foaming) which occurs when milk is carbonated.  
         [0042]    The described arrangements has been advanced by explanation and many modifications may be made without departing from the spirit and scope of the invention which includes every novel feature and novel combination of features herein disclosed.  
         [0043]    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.