Nutritional and Health Benefits of Various Animal's Milk

Taru Negi, Neha Rawat, Deepa Saini and BL Saini

Department of Food Science and Technology, GBPUAT, Uttarakhand-263145, India Division of Animal Genetics, ICAR- IVRI, Izatnagar, U.P., India

Milk is known to be “Mother Nature's most perfect food” and also termed as “complete food for human diet”. Its major components i.e., water, lactose, fat, whey protein and minerals present in different ratio depending on the animal species. These components are essential for the proper growth of the human body. Total milk production and per capita availability of milk in India was 187.7 MT and 394 gms /day, respectively in the year 2018-19. Milk of dairy cattle, buffalo, goats, sheep and camels are dominated in global milk production.

Cow milk

Cow milk is most commonly consumed animal milk, thus largely commercialized globally to make up about 85% of milk global production. It is composed of about 87% water, 3–4% fat, 3.5% protein, about 5% lactose, and 1.2% minerals, with some variation depending on the breed. About 60% of total fatty acids in milk are saturated fatty acids, (palmitic, myristic and stearic acids). Among the unsaturated fatty acids, oleic acid is present in highest concentration. Additionally, essential fatty acids linoleic and alphalinolenic are also present in cow's milk. Oleic acid (monounsaturated fatty acid) is considered to be favourable for health as it lower down the plasma cholesterol, LDL-cholesterol and triacylglycerol concentrations. Cow milk proteins are of high biological value because they contain all the essential amino acids required by the human body, and because of their high digestibility and bioavailability. It stimulates muscle synthesis and have positive health effect e.g. on blood pressure, inflammation, oxidation and tissue development. Milk provides a variety of minerals, in particular calcium and phosphorus, but also potassium, magnesium, zinc, and selenium and both B-group watersoluble vitamins (riboflavin and B12) and fat-soluble vitamins (A and E). Getting enough calcium in the diet gives healthy bones and teeth, and it may also help prevent hypertension, decrease the odds of getting colon or breast cancer, improve weight control and reduce the risk of developing kidney stones. Another mineral i.e. selenium plays an important role in the immune and antioxidant system and in DNA synthesis and DNA repair. Magnesium deficiency has been linked to atherosclerosis and help to reduce asthma. Zinc is an essential part of several enzymes and metalloproteins and known to participate in several functions in the body such as in DNA repair, cell growth and replication, gene expression, protein and lipid metabolism, immune function, hormone activity.

Buffalo milk

Buffalo milk has the high nutritive value compared with cow milk as it is high in water content (84%), protein (3.7%), fat (6.9%), lactose (5.2%) and minerals (0.79%). It has complete proteins of high quality, that is, they contain all the essential amino acids in the proportions required by the body. It is a rich source of most water-soluble and fat-soluble vitamins. Buffalo milk is higher in vitamin A content (340 IU/ kg) than in cow milk (230 IU/kg ) and in calcium content (about 1.5-fold Ca than in cow's milk). It also contains h i g h e r ( 2 6 . 0 m g / 1 0 0 m l )

o l i g o s a c c h a ri d e c o n te n t i n comparison to cow milk (20.3 mg/100 ml).

Goat milk

India (26.3%) and Bangladesh (14.3%) is the largest producer of goat's milk. Due to lower participation of αs1casein (5% of the total casein), it is often considered to be less allergenic than cow milk. Best composition of exogenous amino acids found in the milk of goats. Goat milk contains higher concentration of short-chain fatty acids such as capric acid and caprylic acid which are found useful in therapies for patients suffering from malabsorption syndrome, metabolic disorders, problems with cholesterol, anaemia, bone demineralization and in infant malnutrition. Iron, zinc, and c o p p e r a re p re s e n t i n l e s s concentration. In spite of the fact that iron is present in low concentration, its bioavailability is higher than cow milk as it contains a higher share of nucleotides which contribute to higher absorption in the intestine. Goat milk found high in vitamin A concentration as compared to cow milk. All of the βcarotene of goat milk is converted into retinol and hence, it become more whiter than cow milk. It is a good source of niacin, thiamin, riboflavin, and pantothenic acid. However, it contains 5 times less vitamin B12 and folic acid than cow milk. The lack of these two vitamins in the human diet is thought to result in anaemia. It is found that fat globules of goat milk (3.2 μm) are smaller than that of buffalo's (8.7 μm), cow's (3.95μm), and sheep's (3.78μm) but bigger than camel's (2.99μm). This results in the better digestibility of goat milk in human body, a more efficient lipid metabolism and also a softer texture to goat milk products. Additionally, goat milk has higher calcium, phosphorus, potassium, magnesium, and chlorine and lower sodium and sulfur contents than cow milk.

Sheep milk

Sheep's milk also known as ewe's milk is the milk that has been extracted from the mammary glands of domestic sheep. It is mainly used for the production of fine cheese varieties, yogurt, and whey cheeses as it contain high amount of protein, fat, and calcium. Smaller size of fat globules of sheep milk make it easy digestible than cow's milk. It contains almost twice as much protein as goat and cow milks. These proteins molecular forms and amino acid sequences have nutritional quality, as well as positive impact on digestibility, and thermostability. Sheep milk has higher serine, alanine, histidine, valine, and lysine contents, whereas the cystine and glycine contents are lower. The polyunsaturated fatty acids (PUFAs) in sheep milk fat are mainly comprised of linoleic and α-linolenic acids. Mono and polyunsaturated fatty acids in sheep milk may contribute to the prevention of cardiovascular diseases due to the atherogenic and thrombogenic indices. It is also a rich source of minerals such as calcium, phosphorus, magnesium, zinc, manganese, and copper than cow milk, whereas the opposite appears to be the case for potassium and sodium. The vitamin contents in sheep milk are mostly higher than those in cow and goat milks, except for carotene and folate and vitamin D, which are at equal concentrations to those observed in cow milk. It is favourite among atheletes as it contains one third more energy than cow or goat milk.

Camel milk

Camel milk so called white gold of the desert has valuable nutritional properties as it contains a high propor tion of antibacterial substances and 30 times higher concentration of vitamin C in comparison with cow milk. Camel milk is much more nutritious than that of cow milk because it is low in fat, cholestrol and lactose contents, and higher in potassium, iron and vitamin C, calcium, magnesium, copper and zinc. Additionally, it is more in vitamins A, B2, E and C as compared to cow's milk. The camel milk contains several protective proteins like lysozyme, lactoferrin, lactoperoxidase, NAGase, PGRP, IgG and IgA among them effective one is lysozyme which has the ability to inhibit growth of pathogenic bacteria. These protective proteins help in enhancing immune defense mechanism. Camel milk also contains higher amount of zinc which helps in the development and maintenance of normal functioning of immune system. It is used in the treatment of diseases such as dropsy, jaundice, t u b e r c u l o s i s , a s t h m a , a n d leishmaniasis. It does not contain beta lactoglobulin and beta casein that are present in cow's milk which are the main causative of allergy in humans.

Conclusion

Cow milk proteins known for its high biological value. Sheep and buffalo milk, regarding the high content of protein, including casein, and also fat, make a very good raw material for processing, especially cheese making. Goat milk contains high concentration of short-chain fatty acids that is helpful for treating various diseases and its digestibility is higher than other milk. Camel milk contains 30 times and 6 times more vitamin C than cow and human milk, respectively. It also has valuable nutritional properties as it contains a high proportion of antibacterial substances. r