As a food milk is unique. It has all the food factors:
(1) Proteins. The milk proteins are: casein, lactalbumin and lactoglobulin. Casein, the chief protein occurs combined with calcium as calcium caseinogenate. Milk from cow, buffalo and goat has three times of protein compared to the human milk. The ratio of casein to albumin is nearly 1:1 in the human milk; it is 7:1 in animal milk. Milk protein has all the essential amino acids for body building.
(2) Fat. Its content is 3.10 per cent in the human milk ; in the buffalo milk, it is 7 per cent. Milk fat is a good source of retinol and vitamin D.
(3) Carbohydrates. Lactose or milk sugar is the carbohydrate in all milks; this is unique to milk and is found nowhere else. It is less sweet than cane sugar and is readily fermented by acid bacilli. Human milk has more sugar than animal milk. Fresh cow’s milk yields about 60 kcal or energy per 100 gram.
(4) Minerals. Milk has almost all known minerals needed ..by the body: calcium, phosphorus, sodium, potassium, magnesium, cobalt, copper, iodine and so on. Milk is a specially rich source of calcium and this occurs in an easily assimilable form. It is however a poor source of iron which is just absent in the human milk. The mineral content of the animal milk is two to three times that of the human milk.
(5) Vitamin: There is vitamin A in milk, but the amount is dependent on the feed given to the animal, which can therefore be suitably manipulated. Milk is a rich source of riboflavin but contains very little of Vitamln-C.
Toned milk is an Indian term. This is made by reconstituted milk (using skimmed milk powder and water) with milk having a high fat content such as buffalo milk. When the supply of buffalo milk is restricted, toned milk is prepared from imported butter, fat or butter oil and dried skimmed milk powder. It is much cheaper though quite a wholesome product.