Solubility and heat stability of whey protein concentrates

Rennet whey protein concentrates have excellent nutritional properties, but their use in fluid food systems is impaired by the poor heat stability of the protein. Heating whey protein concentrated solutions at neutral pH caused up to 70% losses in solubility. In the absence of added calcium, protein coagulation occurred. near the iso-electric zone whereas in the presence of .03 M calcium chloride, similar protein coagulation occurred in the whole pH range (pH 2 to pH 12). Tryptic hydrolysis of the protein increased the heat stability of whey protein concentrates considerably.