Séparation et caractérisation des caséines de laits de chèvre et de brebis (Étude comparative)

Abstract

Milk is considered a complete and balanced food because of its richness in several nutrients (proteins, lipids, mineral salts, lactoses and vitamins). the objective of our study is to characterize sheep and goat milk produced in the western regions of Algeria. We analyzed and compared, in a first stage of the work, the physicochemical characteristics of the two original milks sheep and goat. The analyzes performed included pH, density, freezing point, fat, protein and dry matter. The physicochemical analyzes of ewe's milk and goat's milk, respectively, obtained in particular the density (1034.79 vs 1035, 60), freezing point (0.59 ° C. vs. 68 ° C.) and fat (5.48%). vs 5, 27%), dry matter (0.79% vs. 0.78%) and the protein material (3.71% vs. 3.54%). The second stage of our work consisted of the isolation and characterization of the milk caseins. For this, we used the precipitation at pH (pH 4.6) isoelectric casein. The fractions were then monitored by polyacrylamide gel electrophoresis in the presence of urea. Sheep and goat milks differ from each other, but also show significant differences in some criteria. Sheep's milk contains significantly more fat and protein than goat, and more fat-soluble vitamins (A and E). It also has a relatively high calcium content.