Effect of Temperature and pH on Solubility and Aggregation of Whole γ-Casein

The solubility of whole v-casein in citrate-phosphate buffer at pH values from 4.0 to 6.5 and at temperatures of 5, 15, and 25 C was investigated. Solubility decreased with increasing temperature at all pH values. At all three temperatares, the solubility approached a minimum near the isoelectric point of whole casein (pH 4.6) rather than that of y-casein (pH 5.8 to 6.0). Unlike a~and K-caseins, whole V-casein was soluble at all temperatures and pH values. Minimum solubility (.66 mg/ml) occurred at pH 4.5 and 25 C. Sophadex G-100 gel filtration profiles of whole V-casein solutions indicate that both a temperaturedependent and a concentration-deigndent aggregation of whole v-casein occurs.