Associate Professor

Deptt. of Dairy Science & Technology (Formerly A.H. & Dairying)

R.K. (P.G.) College

 Shamli, U.P., India 

Introduction:

In India the major portion of the milk and milk products come from the cows and buffaloes. The milk of other animals is in nowly inferior to that of cow's milk. In country the majority of people holds the cow in great veneration on religious and sentimental grounds and due to this cow's milk is much prized.

In the diet of every nation, milk is an indispensable food items and is considered as nature's perfect food for human beings as well as other animals. The present scientist reaffirm its special and unique value for infants, growing children and youngers.

Milk contain all the constituents essential for the body in considerable amounts except iron, copper and iodine. Milk deficits crude fibre, yet it is good laxative. Major constituents of milk are water, protein, fat, lactose and minerals. Minor milk constituents include phospholipids sterols, vitamins, enzymes, pigments etc.

Milk is only source of lactose which is the principal carbohydrate in the milk. Its maintain the normal condition in the human being intestine and play a significant role in the calcium metabolism and also supply energy casein constitutes about 75% of total protein in milk and it is unique that it is found is milk. Milk protein contain all the nutritionally essential amino acids required for growth and good health. Fat contain all the essential fatty acids so necessary in the human nutrition.

Milk contain all the essential minerals required in human diet. Among the minerals calcium and phosphorus are essential in building the body skeleton as well as muscles including health muscle. In addition to the different constitutions Ca and P both of which together with vit. D are essential for bone formation. Milk is a good source of vitamins which is essential for normal growth, health issues and reproduction of living organism. The milk is so much nutritionally rich that it can be said as nutritional bank.

Carefully controlled experiments with school going children have conclusively proved that effect of milk on the general development and on the mental and physical well-being of the children.

The energy-giving milk constituents and their individual contribution are as follows:

Milk fat–9.3 C/g, milk protein 4.1 C/g and lactose 4.1 C/g

where 1C (Food calorie) = 1000c (Small calories)

on an average cow work furnishes 75C/100 gm. and buffalo milk 100C/100 gm.

Definition Of Milk:

There are several definitions for milk:

(a) General Definition: Milk is the normal secretion of mammary glands of the mammals.

(b) Physiological or Biological Definition: PFA (1976) Rules defined "Milk is normal mammary secretion derived from the complete milking of healthy milch animal without addition there to or extraction there form. It shall be free from colostrum and shall include cow's or buffaloes or goats or sheeps or a admixture there of."

Milk has defined in Davis (1940) "It is the secretion of mammary glands of mammalian animals intended for the immediate nutrition of newly born offspring's of species in questions."

Geneva congress defined "It is an integral product entire and uninterrupted milking of milch cows in good health, well nourished and not overworked. It ought to be collected in proper manner and contain no colostrum.

According to USA federal Milk may be defined as the whole fresh clean lacteal secretion obtained by complete milking of one or more healthy animals excluding that obtained within 15 days before and 10 days after calving and containing not less than 8.5%. Solids-not fat and containing not less than 3.25% milk fat.

(c) Legal Definition: India's legal definition of milk reads milk has been defined as the lacteal secretion obtained by complete milking of milch animals which free from colostrum and cow milk should contain minimum 3.5% fat and minimum of 8.5% S.N.F. Buffalo milk should contain minimum 6% fat and 9% S.N.F. Standardized milk contain not less than 4.5% fat and 8.5% S.N.F. Toned milk contain not less than 3% fat and 8.5% S.N.F. while in case of double toned milk contain not less than 1.5% fat and 9% S.N.F.

(d) Commercial Definition: Market Milk which is sold into market and directly consumed by the consumers. It is processed and pasteurized while term milk refers to generally raw milk which is drawn from the udder of the animal.

Commercially milk is the secretion of cow's udder containing not less than 3.5% fat and 8.5% S.N.F. and in which casein nitrogen constituents not less than 75% of the total nitrogen and which does not clot on boiling.

(e) Chemical Definition: (by some Dairy Scientist) Milk is a complex chemical substances in which fat is present in the form of emulsion, protein mainly casein alongwith some minerals in the form of colloidal state and lactose together with some minerals and whey protein in the form of true solution. Water plays the role of dispersion medium.

Distribution of Constituents of Cow Milk:

The composition of milk of all mammals consists of the same constituents though in varying proportions. The major constituents present in milk are water Fat, lactose Protein and mineral (ash). The milk has broadly two parts viz. water and the total solids (T.S.) by substracting the water content out of 100, the remaining solids part is called total solids. These total solids are again fat and solids-not-fat (S.N.F.). Less fat out of the total solids is the S.N.F. S.N.F. includes the milk protein, lactose and ash (minerals), vitamins & pigments and enzymes.

Average Composition of Cow milk for some Indian breeds

Indian Breeds	Water %	Total Solids % (T.S.)	Solids not fat (S.N.F.) %	Fat %	Total Protein %	Lactose %	Ash %
Red Sindhi	86.17	13.83	8.93	4.90	3.42	4.81	0.70
Thar Parkar	86.58	13.42	8.87	4.55	3.36	4.83	0.68
Sahiwal	86.42	13.58	9.03	4.55	3.33	5.04	0.66

Source: Average complied from various sources.

Average Composition of Cow milk for some Foreign breeds

Foreign Breeds	Water %	Total Solids % (T.S.)	Solids not fat (S.N.F.) %	Fat %	Total Protein %	Lactose %	Ash %
Jersey	85.27	14.73	9.36	5.37	3.73	4.93	0.70
Holstein	87.77	12.23	8.69	3.54	3.29	4.68	0.72
Brown Swiss	86.69	13.31	9.32	3.99	3.64	4.94	0.74
Ayrshere	87.07	12.93	8.93	4.00	3.58	4.67	0.68
Guernsey	85.47	14.53	9.58	4.95	3.91	4.93	0.74

Source: Average complied from various sources.

Average milk composition of selected breeds of Buffalo

Breed of Buffalo	Water %	Total Solids % (T.S.)	Solids not fat (S.N.F.) %	Fat %	Total Protein %	Lactose %	Ash %
Murrah	83.56	16.44	9.44	7.00	3.72	4.95	0.77
Jaffarabadi	83.18	16.02	9.52	7.30	3.70	5.01	0.81
Surti	82.07	17.93	9.53	8.40	3.67	5.06	0.80

Source: Milk and its products NCERT (1991).

Average chemical composition of milk of different species

Species of animals	Water %	T.S. %	S.N.F.%	Fat %	Total Protein %	Lactose %	Ash %	Energy (Kcal)
Cow	87.00	13.00	9.00	4.00	3.50	4.70	0.80	70
Buffalo	83.50	16.50	9.50	7.00	3.90	4.80	0.80	101
Goat	87.00	13.00	8.80	4.20	3.65	4.30	0.85	68
Sheep	81.50	18.50	10.60	7.90	4.90	4.80	0.90	111
Camel	87.25	12.75	7.35	5.40	3.00	3.60	0.75	73
Human	88.00	12.00	8.75	3.25	1.50	7.00	0.25	66

Source: Complied from various sources.

References:

1. Jenness Rand Patton S. (1959). Principles of Dairy Chemistry, John Wiley's U.S.A.

2. Ling, E.R. (1956). A Text Book of Dairy Chemistry, Vol. 1 & 2, Chapman and Hall, London.

3. Mathur, M.P., Datta Roy, D. and Dinakar (1999). Text Book of Dairy Chemistry, ICAR New Delhi.

4. Webb, B.H. & Johnson A.H. (1979). Fundamental of Dairy Chemistry, AVI Publishing Co., Connecticut, U.S.A.

5. Singh, T.B. & Shukla, S.G. (2014). Dairy Chemistry & Animal Nutrition, Rama Publishing House, Meerut.

6. Jauhar, I.J. & Gupta Ramji (2022). Food Process up & safety issue, Ram Publishing House, Meerut, ISBN-978-93-88821-43-8.

7. Saraswat, B.L. and Agarwal, J.P. – Dairy Chemistry & Animal Nutrition, Kushal Publication & Distributor, Varansi.