Proteins Profile in Milk from Three Species of Ruminants

Abstract

Milk proteins, caseins and whey proteins, are very important nutritionally, as they contain all essential aminoacids in optimal proportions and are the most important source of bioactive peptides. These peptides are protein fragments resulting from enzymatic hydrolysis of milk proteins, which carry numerous beneficial effects on the cardiovascular, nervous, gastrointestinal and immune systems. In this research, total proteins, caseins and whey proteins respectively, were dosed in milk from three species of ruminants-cow, goat and sheep, using a very sensitive method, Bradford photometric method. The highest content of total proteins was obtained in sheeps’ milk (65.92 mg/ml) and the lowest in cows’ milk (40.03 mg/ml), intermediate values occurring in goats’ milk (46.79 mg/ml). The lowest amount of caseins was found in cow milk (28.26 mg/ml), followed by sheep milk (42.55 mg/ml) and goat milk (44.03 mg/ml). When the case of whey proteins, the highest values occur in sheep milk (23.36 mg/ml) and the lowest in cow milk (11.79 mg/ml), goat milk having intermediate values (17.7 mg/ml). The results obtained indicate the dependence of protein concentration in milk of the studied ruminant species and stresses the importance of including goat and sheep milk in daily diet, along with cow milk, for an optimal intake of protein.