The determination of the zeta potential of casein micelles

Abstract

SUMMARYThe principle of moving boundary electrophoresis has been employed for the measurement of the electrophoretic mobility and subsequent calculation of zeta potential of bovine casein micelles. The zeta potential of casein micelles was observed to increase with increase in temperature (from 10 to 50 °C) and to decrease with decrease in pH. Heat treatment of milk between 90 °C/30 min and 135 °C/50 min had no significant effect on zeta potential. The zeta potential of casein micelles during rennet action decreases until all the κ-casein has been cleaved by the enzyme.The results of this study indicate that electrostatic interactions alone are not sufficient for an understanding of the absolute stability of casein micelles.