Résumé:
The cattle milk is very busy in Algeria, in order to meet the needs of the population which is
constantly increasing and who consumes the milk in the fresh state or transformed many are
the manufacturers who transforms the milk products derived mainly cheese. For the latter
case, it established that only milks possessing αs1 exprimée avec fort pourcentages1 casein expressed with a high percentage
could give rise to the manufacture of cheeses.
For that, we conducted a study, which aims at first to evaluate the amount of casein produced
in these milks of western Algeria. The results obtained show that the casein fraction was
higher in spring (80.52%) which coincides with the period of high lactation against 79.75%
for winter milk.
In a second step, we proceeded to the isolation and the characterization of the caseins. For
this, we used the isoelectric pH precipitation of caseins (pH 4.6). The fractions were
monitored by polyacrylamide gel electrophoresis in the presence of urea. The resulting
electrophoretic profiles made it possible to identify the presence of 04 bands, which
correspond to the caseins αs1 exprimée avec fort pourcentages1, αs1 exprimée avec fort pourcentages2, β and K casein. The quantification of the latter showed
some differences between the milks obtained during the two seasons when casein αs1 exprimée avec fort pourcentages1 was
greater in spring 41.10% against 38.80% in winter.
The use of PAGE-urea is more suitable for the study of casein profiles.
