EFFECTS OF PH, SODIUM-CHLORIDE AND CALCIUM-CHLORIDE ON HEAT AGGREGATION OF WHEY-PROTEIN CONCENTRATE AND WHEY-PROTEIN ISOLATE

To improve utilization of whey protein concentrate (WPC) and whey prot ein isolate (WPI), effects of pH, sodium chloride (NaCl) and calcium c hloride (CaCl2) on heat aggregation of WPC and WPI were investigated b y determining changes in turbidity and viscosity. A time course of tur bidity was measured by heating at 2-degrees-C/min from 30-degrees-C to 95-degrees-C. The turbidity of WPC and WPI solution at pH 5.0 was inc reased from 75-degrees-C. The rate of turbidity of WPI solution was hi gher than that of WPC. Turbidity changes of WPC and WPI solution were observed from addition of 50mM NaCl and 100mM NaCl, respectively. The turbidity of WPC solution by addition of 1mM CaCl2 was increased from about 72-degrees-C. The turbidity changes of WPI solution by addition of 1, 2, 5 or 10mM CaCl2 were sharply increased at the temperature fro m 72-degrees-C to 82-degrees-C, from 65-degrees-C to 75-degrees-C, fro m 55-degrees-C to 70-degrees-C, and from 50-degrees-C to 65-degrees-C, respectively. When WPC and WPI solution were heated at 80-degrees-C f or 15min, viscosity of those was determined. There was little effect o f pH on viscosity of WPC and WPI solution. Viscosity of WPI solution a dded 200mM NaCl was markedly increased by heating. The viscosity of WP I solution was increased by addition of CaCl2, and furthermore it was remarkably changed by heating. These results suggested that desirable coagulates of WPI were formed by adjustment of pH and addition of CaCl 2.