Patent IE-33309-B1 (IE)
Title: Improvements in or relating to foodstuffs
IPC: A23L9/20
Filed: 1969-09-02
Abstract: Cheese is made from an emulsion which contains a fat fraction including at least 25 percent non-milk fat, fat-free milk solids, butter serum and buttermilk. This invention relates to foodstuffs and, in particular, to foodstuff intermediates suitable for the production of cheeses. Cream substitutes made from animal or vegetable fats, skim milk and an emulsifier are generally known. For instance, in the U.S.A. whipping cream mixtures have been marketed in which a portion and preferably all the milk fat is replaced by vegetable fat. These products, which often include flavoring materials such as sugar and vanilla, are especially suitable for individuals having a high cholesterol count in the blood or who, for other reasons, have a low toleration of milk fat. Such diet foods are normally manufactured by mixing together the ingredients in the appropriate proportions and subjecting the mixture to light homogenization to avoid too rapid a separation of the fat. Cheeses are usually made by processing a product comprising natural whole milk and/or cream and customarily have milk fat contents as high as 60 percent by weight. Thus, as in the case of cream substitutes, there is a real need to reduce the amount of milk fat in cheese without affecting the special characteristics thereof. Although the consistency of a cheese is governed largely by fat content, its flavor is influenced to at least as high a degree by the nature of the starting material. It is an object of the present invention to provide novel intermediates from which cheeses can be produced of reduced milk fat content as compared with conventional cheese made from natural whole milk and/or cream. It is another object of the invention to provide novel intermediates from which cheeses can be produced having a similar taste or flavor to those made from natural whole milk and/or cream. According to the present invention an emulsion product suitable for producing cheese comprises up to 85 weight percent fat, of which fat at least 25 weight percent is non-milk fat, emulsified in a low fat milk fraction having a fat-free milk solids content of from 6 to 12 weight percent. Also according to the invention are cheeses prepared from the aforesaid emulsion product. More usually, the emulsion product contains a major proportion of non-milk fat and, if desired, the whole of the milk fat can be replaced. In the preparation of the emulsion product, the fat is emulsified into the low fat fraction, preferably at an elevated temperature of, said, 50.degree. to 60.degree.C, by appropriate mechanical means, such as by circulation pumping with a centrifugal pump. In this way, an emulsion is obtained substantially without free fat. In a modified procedure in accordance with the invention, this emulsion can be separated into fat-rich and fat-poor fractions, the former fraction containing, for example, about 15 weight percent fat. The fat-rich fraction is then homogenized prior to being mixed together with the fat-poor fraction to form the emulsion product from which the cheese is to be made. A cheese according to the invention can be made from such emulsions using any of the procedures and equipment which are standard in the industry. It is generally known that the milk fat in milk is present in the form of a large number of dispersed particles which are mainly spherical in shape. These particles are surrounded by certain materials which collect on their surfaces and maintain the particles dispersed in the aqueous phase. These materials which include albumins, globulins and phospholipoids such as lecithin and hephalin, thus form a boundary layer between the fat globules and the aqueous phase and microscopic examination of milk and cream has shown each fat particle to be enclosed by a membrane or film of such materials. Such membranes are unimolecular and their combined lipophilic and hydrophilic properties are believed to confer the relatively good stability which the fat emulsion of natural milk possesses. An important aspect of the present invention is based upon the discovery that the taste or flavor of cheeses is governed only to a small extent by the type of fat they contain. What is considerably more significant is the composition of the membrane or film by which the fat globules of the starting material are bounded. Inasmuch as phospholipoids per se are unsatisfactory, a possible explanation is that complex compounds are formed between the former and milk proteins. Thus in manufacturing cheese substitutes, the composition of the membrane or film should be as similar as possible to that forming the boundary layer in natural milk or cream if the flavor of genuine cheese is to be achieved. The term "low fat milk fraction" in this specification refers to a variety of extracts, including mixtures thereof, which can be separated from milk or from solid or liquid emulsions derived from milk, such as cream and butter, and which contain to varying extents the aforementioned membrane- or film-forming substances. Typical low fat milk fractions containing the membrane-forming substances are skim milk, buttermilk as well as various serums which can be extracted from milk, cream and butter by removing butter oil. Butter oil serums remaining after refining butter oil to higher degrees of purity provide additional important sources of these substances. It will be appreciated that the quantity of membrane-forming substances present in a low fat milk fraction can vary over quite wide limits depending upon what the fraction is and the manner in which it has been prepared. For example, skim milk has a lower concentration of membrane-forming substances per unit volume than a cream separated from the original milk and hence buttermilk separated on churning that cream to butter has a concentration of membrane-forming substances per unit volume many times that of skim milk. In turn, a serum prepared form this butter has a concentration of membrane-forming substances several times that of buttermilk. Furthermore, the higher the milk fat content of the cream, the higher the concentration of membrane-forming substances in the buttermilk extracted therefrom. Moreover, as the milk fat content of a skim milk increases so increases the amount of membrane-forming substances per unit volume. It is usual to separate cream from milk at a temperature of from 40.degree. to 45.degree.C. However, experience has shown that as the temperature is increased, the concentration of membrane-forming substances in the cream decreases while that of the skim milk correspondingly increases. The amount of membrane-forming substances present in the emulsion product of the invention is of real significance since too high a quantity prevents the separation of whey during cheese production while too little results in the separation of free fat. At the same time, the fat-free milk solids content (sometimes referred to as the milk solid non-fat or MSNF content) of the low fat milk fraction is extremely important if a satisfactory cheese is to be obtained, a range of from 9 to 10 weight percent being found to be especially convenient, Generally speaking, a low fat milk fraction having a MSNF content exceeding 12 weight percent results in a cheese which is too dry, while with a MSNF value below 6 weight percent a fatty product is obtained having a consistency somewhat resembling that of mayonnaise. An upper limit of 85 weight percent fat is specified above for the emulsion product since with fat contents exceeding this figure, a phase-exchange takes place from the desired fat-in-water emulsion to a water-in-fat emulsion. However, it is more usual to prepare the cheese from an emulsion containing from 3 to 5 weight percent emulsified fat, although fat contents as low as 0.03 weight percent have been used for certain cheeses. Emulsions of higher fat content can be readily diluted to this level by the addition of skim milk. Non-milk fats which can be employed in producing the emulsion products of the present invention include vegetable and animal oils. Examples of such oils are cocoa nut oil, palm oil, cotton seed oil, ground nut oil, soya bean oil, olive oil, corn or maize oil, sunflower oil, whale oil and lard. Preferably, vegetable fat mixtures are used which melt between 25.degree. to 35.degree.C. Such a mixture can conveniently consist of liquid and solid soya bean oil and semi-solid sunflower oil. A mixture which has proved to be especially suitable in practice has soya bean oil and semi-solid sunflower oil present in respective amounts of from 30 to 40 weight percent and 25 to 35 weight percent with the balance being liquid soya bean oil. Skim milk produced from natural milk by separating cream having a fat content range of from 20 to 40 percent by weight is a source of appreciable quantities of membrane-forming substances. However, skim milk which remains after separating, for example, a 35 percent cream (a cream containing about 35 weight percent milk fat) from natural whole mil, while possessing a satisfactory MSNF content, has per se too low a concentration of membrane-forming substances per unit volume for making most cheeses. For preparing suitable low fat milk fractions in which the fat can be emulsified, it has been found convenient to add to such a skim milk predetermined quantities of, for example, buttermilk and cream or butter serums as well as mixtures thereof. The proportions of the ingredients used in preparing the low fat milk fractions depend on their respective contents of membrane-forming materials and fat-free milk solids. Thus mere concentration of a skim milk to increase its membrane-forming material percentage can result in a MSNF percentage which is too high. However, since skim milk, buttermilk and cream and butter serums prepared from the same natural milk source have progressively lower MSNF contents, the addition to skim milk of one or other of the remaining fractions enables the proportion of membrane-forming materials in the resulting low fat milk fraction to be adjusted to the desired level without raising the overall MSNF percentage as compared with skim milk. Suitable low fat milk fractions include those containing (a) skim milk and buttermilk in a ratio of from 2:1 to 1:2 by volume, (b) 10 to 20 volume percent butter serum with the balance being buttermilk, and (c) about 5 volume percent butter serum, 30 to 40 volume percent buttermilk with the balance being skim milk. The skim milk, in this instance, is that obtained by separating 20 to 40 percent cream from a natural milk containing, for example, 5 weight percent milk fat, the buttermilk that obtained by churning the 20 to 40 percent cream to butter and the butter serum that obtained by separating butter oil from the butter. The butter serum is preferably separated from a non-acidified, unsalted butter, although for making certain cheeses an acidified, salted butter can be employed. This can be done quite simply by melting the butter and centrifuging out an aqueous lipoid fraction which constitutes the butter serum. The butter oil so obtained finds application as the fat raw material for use in recombining, a 99.5 percent pure butter fat being preferred because of its extreme durability, in contrast to butter, which turns rancid on storage. Butter oil can also be separated from natural whole milk or cream by utilizing various special types of homogenizers or similar apparatuses which operate on a centrifugal principle. An example of such an apparatus is the "Clarifixator" manufactured by AB Separator of Sweden. A description of the apparatus is to be found in the article "From Idea to Product" appearing at page 15 to 22 of the 75th Jubilee Memorial Publication of the Association of Swedish Inventors, Stockholm 1961. By carefully selecting the operating conditions, butter oils can be readily removed at temperatures above 32.degree.C, and preferably from 50.degree. to 55.degree.C, having varying degrees of purity from, say, 85 percent upwards. Moreover, a butter oil of, for example, 85 percent purity can be purified in this manner still further to a degree of purity close to 100 percent, leaving behind a butter oil serum having a concentration of membrane-forming substances similar to that of a butter serum, that is a serum obtained by separating butter oil from butter. The components of the low fat milk fraction, as well as the fraction itself, can be utilized in a concentrated or dried condition provided appropriate quantities of water are added. Where sterilization is effected, it is necessary to replace the original cheese-forming bacteria destroyed thereby. It is not customary to use buttermilk alone because it generally has too low a MSNF value. However, this difficulty can be overcome by concentration and/or the addition of buttermilk powder or skim milk powder. Moreover it has been found that where a buttermilk/skim milk mixture contains somewhat less than the desired content of membrane-forming materials, the emulsifying properties of the low fat milk fraction can be improved by simply adding a conventional emulsifier. Thus where the ratio of skim milk to buttermilk is of the order of 3:1 by volume, the skim milk being obtained from, for example, a 5 percent natural milk by separating a 20 to 40 percent cream and the buttermilk by churning this cream to butter, the addition of 0.2 weight percent of emulsifier results in a satisfactory low fat milk fraction. Examples of emulsifiers which can be used in preparing the low fat milk fractions are the mono- or diglycerides of fatty acids such as monostearic and dipalmitic acid; polyoxyalkylene ethers of fatty acid esters of polyhydric alcohols such as polyoxyethylene ethers of sorbitan monostearate of polyoxyethylene ethers of sorbitan distearate; fatty acid esters of polyhydric alcohols such as sorbitan monostearate; mono- and diesters of glycols and fatty acids such as propylene glycol monostearate and propylene glycol monopalmitate; and partial esters of carboxylic acids such as lactic acid, citric acid and tartaric acid with mono- and diglycerides of fatty acids such as glycerol lactopalmitate and glyceryl lactooleate. Fatty acids which can be used in producing these emulsifiers include those which are extracted from beef tallow and cocoanut oil, cotton seed oil, palm oil, ground nut oil, soya bean oil and marine oils. The emulsion product of the invention can also be made to incorporate vitamins which have a slight emulsifying effect. Cheeses have been made containing at least one of vitamins A to E with a total vitamin content of 20,000 units per kilogram. While it will be readily appreciated that the primary purpose of the invention is to provide emulsion products from which novel cheeses can be prepared, these products also find useful application in the manufacture of icecream.[US3716377A]