Isoélectrofocalisation des lactosérums de fromages de mélange brebis-vache sur gel de polyacrylamide. Application à la recherche et au dosage du lait de vache dans les fromages de brebis

Abstract

Summary - Isoelectric focusing of wheys of mixture milk cheeses ewe-cow in polyacrylamide gel. Application to evaluation of cow's milk in ewe's cheeses. Farm type cheeses made from a mixture of ewe's and cow's milk were ripened in a cellar over a period of 1 to 4 months. The whey from these cheeses was extracted and analysed by isoelectrofocusing (IEF) on polyacrylamide gel (gradient 4-6). Specifie bands of cow's and ewe's milk were identified. Densitometric analysis of the IEF patterns were used to calculate the density coloration ratios of the CIE bands; C and E corresponding bands chosen to characterize cow and ewe's milk respectively. From the expression of this ratio, according to the percentage of cow's milk in the mixture, an abacus was established. This abacus was used to assess the quantity of cow's milk added to ewe's milk during the manufacture of cheeses.