Heat-induced modifications of the functional properties of sodium caseinate

The effects of heating sodium caseinate solutions (5-6%, w/v, pH 7.0) at 120 or 132 degrees C for 60 min on functionality were investigated by measuring solubility, viscosity, foaming and emulsifying properties. Solubility of the protein at pH 2.0-3.5 was increased markedly by the heat treatments, but there was little change at pH values above 5.5. The viscosity of Na caseinate solution was decreased by the heat treatments. Heating reduced significantly the foaming and emulsifying capacity of Na caseinate, but the foam stability appeared to be improved by the heating. The drainage of liquid from the foam appeared to follow first-order kinetics. The relative hydrophobicity also was reduced by the heat treatments. (C) 1996 Elsevier Science Limited