Nutritional ingredients cow's milk

Cow's milk is a rich source of high quality proteins, fats, carbohydrates, vitamins a, b and mineral elements (Annex B, table. 13-15). It in sufficient quantities contains all essential amino acids. At the same time in milk is not enough iron and vitamins C and D. In many countries marketed pasteurized milk, usually fortified with vitamin D (400 IU/l). In patented milk mixtures, prepared on the basis of cow's milk, add other vitamins and sometimes iron.
The protein content in whole cow's milk varies from 2.8 d 4.1 g per 100 ml, on average amounting to 3.3 g/100 ml (table. 3). The two main protein components of cow's milk is casein, which constitutes about 80%, and serum proteins that make up about 20%. The number of individual proteins can be different and depends on the period of lactation, livestock breeds and use of feed; thus proteins in qualitative terms, apparently, little change [2].
State of cow's milk are colloid complexes with phosphate of calcium. Four main casein called alpha, beta, gamma and Kappa; electrophoretic mobility them at alkaline pH is reduced from alpha to Kappa, relative molecular mass varies from 18 000 to 24 000 [4]. Beta-lactoglobulin, the primary protein of milk whey, consists of two identical polypeptide chains, molecular weight of each of which is about 18 000 daltons. The term "lactalbumin" can be misleading, because this protein fraction of serum milk contains a heterogeneous group of protein, soluble in saturated ammonium sulfate. Alpha lactalbumin cow's milk protein consisting of a single polypeptide chain with relative molecular mass of about 15 000 daltons. Serum albumin is also composed of a single polypeptide chain, relative molecular mass of which is about 68 000 daltons. Immunoglobulins are around 2% cow's milk protein (most of them are found in colostrum), and the number of IgG - largest, IgM - average and IgA least. Casein and beta-lactoglobulin synthesized directly in the breast of amino acids, coming down from the blood; they are not associated with any of plasma proteins [4]. Beta-lactoglobulin consider pure protein, but a comparison of protein preparations isolated from different cows, testifies to their heterogeneity. By electrophoresis in starch gel identified 3 genetic forms of beta-lactoglobulin, called a, b and C, depending on their degree of mobility. In the body of each animal is synthesized one of these beta lactoglobulin or two of them in any combination. It should be noted that immunological all three forms are identical [5].
Only carbohydrate in milk is lactose; the number varies from 4.5 to 5 g per 100 ml, in the average of 4.8 g/100 ml
The fat content in milk is 3.1-5,2 g/100 ml (an average of 3.7 g/100 ml), i.e. changing more than the content of any other element. Cream contain mostly triglycerides: olein, palmitin and stearin and less cholesterol. Whole cow's milk cholesterol is 9-17 mg/100 ml, and in the removed - only 0.4 mg/100 ml
Saturated fatty acids contained in 2,5 times more than unsaturated.
Whole milk contains 20 calories per oz *, 50% fat, 30% carbohydrates, and 20% from protein.
More detailed information about the biochemistry of cow's milk can be gleaned from a number of works [6-10].

* An ounce is equal to 28.3 g - note. Ed.