Characterization of milk proteins from different animal species through gel electrophoresis

Abstract

Present investigation covers the chemical composition, nitrogenous compounds and protein fractionations of casein and whey proteins of milk from different dairy animals like buffalo, cow, sheep, goat and camel. The buffalo and sheep milks have comparatively higher fat, solid-not-fat and total solid contents than other milks. Maximum whey proteins were found in the sheep milk (0.78%) whereas cow milk had lowest contents (0.54%). Non-casein-nitrogen (NCN) contents in sheep milk were higher followed by camel and buffalo milks. Electrophoresis study of caseins on Urea-PAGE showed darker bands of aS1-CN and β-CN in sheep, buffalo, goat and camel while k-CN band only appeared in buffalo's milk. The aS2-CN was found to be absent in camel milk whereas merged in buffalo and sheep with aS1-CN. Electophoretic mobility of aS1-CN in goat and sheep milk was higher than buffalo milk. Examining the SDS-PAGE of whey proteins of these species, β-Lg was found to be the major protein in sheep and buffalo milks, while in goat it was the second predominant protein and it was absent in the camel milk. The concentration of immunoglobin was found higher in camel and goat milks as compared to other species. Moreover, the strength and mobility of bovine serum albumin (BSA) was different in all milk species.