Résumé:
The objective of the study is to identify the qualitative aspects of cow's milk produced in the western region of Algeria. Mixed milk analyzes during the summer and fall seasons show different fat levels between the two seasons (34.07 g / l ± 0.74 vs 32.88 g / l ± 0.84) below the reported values. By literature. On the other hand, these milks have higher or lower protein contents compared to milks produced in Algeria, especially in autumn (33.14 g / l ± 0.81 vs 32.7 g / l ± 0.89). In this fraction caseins present 80.6% of total proteins in summer and 78.93% in autumn. The analysis of the casein fraction under electrophoretic separation conditions gave profiles with a high similarity and homogeneity of electrophoretic mobility between the different samples of the milks of the two seasons. However PAGE urea analyzes demonstrated that the content of main caseins vary in the following proportions: β casein from 33.44% to 43.31% in summer and from 37.45% to 43.65% in autumn, αs1 casein from 38.71% to 44.20% in summer and from 39.14% to 43.74% in autumn, αs2 casein from 5.9% to 21.60% in summer against 5.18% to 13.86% in autumn, finally Kappa casein from 7.58% to 9.65% in summer versus only 5.22% to 11.42% in autumn. The ratio αs casein / β casein was better in the autumn of the order of 1.24 against 1.14 in the summer period.
