Influence of NaCl and CaCl2 on cold-set gelation of heat-denatured whey protein

Heat-denatured whey-protein isolate (HD-WPI) solutions were prepared by hea ting a 10 wt% WPI solution (pH 7) to 80 degrees C for 10 min and then cooli ng it back to 30 degrees C, Cold-set gelation was initiated by adding eithe r NaCl (0 to 400 mM) or CaCl2 (0 to 15 mM). Both salts increased the turbid ity and rigidity of the HD-WPI solutions. Gelation rate and final gel stren gth increased with salt concentration and were greater for CaCl2 than NaCl at the same concentration because the former is more effective at screening electrostatic interactions and can form salt bridges.