MULTIPLE-REGRESSION AND RESPONSE SURFACE-ANALYSIS OF THE EFFECTS OF CALCIUM-CHLORIDE AND CYSTEINE ON HEAT-INDUCED WHEY-PROTEIN GELATION

Multiple regression analysis was used to obtain prediction equations to measure individual and combination effects of CaCl2 and cysteine on gel texture parameters (hardness, cohesiveness, and springiness) and on compressible water of dialyzed whey protein concentrate (WPC) systems. Predicted maximum gel hardness occurred at11.1 mM CaCl2 or 9.7 mM cysteine. Cysteine levels at 30 mM or above drastically reduced gel hardness.Cohesiveness tended to decrease with addition of either reagent. Reagent addition generally decreased gel springiness while compressible water increased. Response surface contour predictions suggested that increases in CaCl2 or cysteine in reagent combination systems decreased hardness and increased compressible water. Predicted cohesiveness and springiness maxima were at 13.9 mM cysteine and 18.4 mM CaCl2 and at 10.3 mM cysteine and 10.0 mM CaCl2, respectively. Significant 2 interaction terms in the mathematical model for combined reagent effects were observed on hardness, cohesiveness, and compressible water in the WPCgel systems. © 1979, American Chemical Society. All rights reserved.