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 heating a 10 wt% WPI solution (pH 7) to 80 degrees C for 10 min and then cooling it back to 30 degrees C, Cold-set gelation was initiated by adding either NaCl (0 to 400 mM) or CaCl2 (0 to 15 mM). Both salts increased the turbidity and rigidity of the HD-WPI solutions. Gelation rate and final gel strength 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.