![]() Similarly the Ascorbic acid concentration is also low. ![]() The vitamin D content of milk is very small. Milk is a good source of Vitamin A and its precursors. Lactose increases the intestinal absorption of Ca and P. This factor has complex polysaccharides in its structure. A factor named bifidus occurs in milk which favors the growth of Lactobacillus bifidus in the intestine of the breast-fed infants. This process involves the conversion of lactose to lactic acid ethyl alcohol and CO2 are also produced. If due to bacterial contamination milk lactose gets fermented, the milk becomes sour. Lactose is the chief sugar of milk two other sugars namely gynolactose and allolactose are also present. Cow’s milk has about 11 mg cholesterol per 100 ml, all of which is free. Milk has also essential fatty acids and cholesterol. The most abundant fatty acid occurring in milk is oleic acid. But in human milk, fatty acids are of a chain length above 10C. Cow’s milk triglycerides contain fatty acids ranging in chain length from 4C to 20C. ![]() Milk is an oil in water emulsion which is made stable by phospholipids and proteins of milk which are absorbed on the surface of the small-sized fat globules. Lactoglobulin is least abundant milk protein this fraction contains antibodies as well. Lactalbumin is also not a single protein but there are at least three types of this protein. The cow’s milk has relatively more casein than human milk and therefore it makes tough curds as compared to human milk. Paracasein then combines with Ca++ ions to form calcium paracaseinate which gives rise to curds. In the first step, casein is partially hydrolyzed giving rise to paracasein.Ĭasein -> Paracasein (Partial hydrolysis) The proteolytic enzymes, rennin, pepsin and chymotrypsin, can produce curdling of milk which takes place by following mechanism for which Ca ++ ions are essential. The reaction is given below.Ĭa-caseinate + 2HCL -> Casein + CaCl 2 Casein is low in methionine and threonine.Ĭasein can be precipitated by adding an acid to milk. Casein, however, is not a single protein but there are several types of casein which differ from each other mainly in respect to phosphorous content. It is a phosphoprotein and its isoelectric pH is 4.6. These are casein, lactalbulmin and lactoglobuline.Ĭasein is the characteristic and most abundant protein of the milk. Milk has proteins, lipids, carbohydrates, vitamins enzymes and many organic constituents. The exact composition of milk varies with the breed of cattle, the feed used and the period of lactation. Fresh milk does not coagulate on boiling but a surface film is produced that contains casein and calcium salts.Ĭhemical Constituents of Milk Chemical Constituents of Milk Milk is slightly acidic with a pH between 6.6 and 6.9. Its specific gravity ranges from 1.026 to 1.036. Physical Characteristics: Milk is a liquid a white to yellowish white color due to substances such as carotenes and xanthophylls dissolved in milk fat. The chief essential dietary ingredients which are less or absent in milk are the two minerals name iron and copper both needed for red blood cell formation. This high nutritional value of milk is quite useful to mammals because milk remains the only food for the young mammal for long period. Milk is nutritionally one of the best food items.
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