The invention describes a method of manufacturing low calorie frozen dessert with little or no fat content. Ice creams have been perennial favourites as desserts. The palate has grown accustomed to the richness, creaminess and taste of ice creams. Present day emphasis on a low-fat diet has caused health concious people to cut back on the fat and cream in ice cream, and hence the world over people are seeking techniques for making low calorie frozen desserts. One such low calorie frozen dessert is sorbet.
Normal sorbet is made out of water, fruit pulp and/or flavor along with appropriate emulsifiers and stabilizers. It is light, fresh tasting and fluffy when consumed fresh on site. The difficulty with normal sorbet is that it tends to melt quickly and, in cold storage, tends to collapse in to an icy mass, thus having a very limited shelf life.
The present invention describes for the first time a frozen dessert from milk whey which may be clarified or used as is, depending upon the extent of fat and smoothness desired in the end product. The frozen dessert, which is a kind of sorbet has the much desired low-fat and low calorie value and the lightness, fluffiness and fresh taste of sorbet, and is akin to ice cream in its creaminess, smoothness, appearance and mouth-feel. In addition, it has a reasonable shelf life.
Whey is the serum remaining after most of the casein and fat from the milk has been removed, but still contains lactose, minerals, dissolved fat and proteins, often referred to as whey proteins. Whey is a voluminous bi-product of the cheese making industry. The use of whey in the form of whey powder of various concentrations of proteins, fat and lactose has been known for some time in the manufacture of ice cream, especially as a cheaper substitute for milk or nonfat milk solids. However the commercial cost of manufacturing whey powder is quite high, which adds to the final cost of ice cream made using whey powders.
In U.S. Pat. No. 4,840,813, of 1989 a method of preparation of low-fat or non-fat frozen desserts using whey protein concentrates has been described. The multi-stage method described in this patent is both complex and elaborate.
In Canadian Patent WO 92/20239, the inventors have described a denatured whey protein product, which can be used in the production of dairy products especially ice cream. This method again is an expensive and complex process, which involves concentrating the heat treated whey.
In Canadian Patent No: WO/16637, the inventors have described the preparation of a whey product with extended shelf life, which could be a frozen beverage, made from defatted whey to which an adjuvant is added, and the adjuvant is usually a milk protein preparation.
In Japanese Patent No: 61 224939 A, the inventors have described a method of preparing ices by freeze-agitation and aeration of milk whey(full whey). Ices prepared from full whey tend to be very opaque and heavy, and with very little creamy quality.
In U.S. Pat. No. 5,547,697, the inventors have described a method of preparing a zero fat whipped dessert comprising of milksolids non-fat, whey solids or mixture thereof. The invention describes an emulsion prepared from wheysolids, or milksolids using water or water containing liquid including whey. Zerofat as used herein is intended to mean that no fat is intentionally added to the whipped cream frozen dessert product and the ingredients used are substantially fat free. It has however made exception to the presence of fat traces present in milk solids not fat and small of triglycerides present in the emulsifiers used.
Loewenstein et al, 1975 have described a process wherein neutralised clarified whey has been hydrolised prior to the concentration process. The neutralised clarified whey is obtained by addition of potassium hydroxide, which precipitates out the protein. No mention has been made as to whether the clarified whey so obtained still contains the dissoved and undissolved fat. Concentrating whey to obtain whey solids is an expensive process, involving high energy costs, which makes the end products using an emulsion of whey solids or addition of whey solids commercially unviable. Further the whey used in all known methods is whole whey which normally contains substantial amounts of dissolved and undissolved fat and protein.
The present invention describes for the first time the preparation of a frozen dessert more akin to sorbet, from liquid milk whey, wherein the undissolved fat has been removed and if desired, the whey is further suitably treated to remove the dissolved fat and proteins to obtain clarified whey.
Clarified whey is the serum after the dissolved fat and protein have been removed, leaving behind the minerals, lactose, all water soluble vitamins, inorganic nitrogen compounds, peptones and some polypeptides.
Sorbet made out of clarified whey instead of water thus has the positive characteristics of sorbet, while mitigating some of the limitation of normal sorbet. The physico chemical properties of whey, including its colloidal properties promote locking in of air and foaming and allow for sorbet made out of whey to have the smoothness without ice crystal formation, the lightness, the fluffiness and mouth-feel akin to ice cream, without the high calorie and fat of ice cream. Its slow melting and storage behaviour allows for longer shelf life of the sorbet-like product. This invention describes a simple, low cost method for producing an essentially fat-free frozen dessert using milk whey preferably, clarified milk whey.