Effect of Sodium Chloride on the Solubility of Caseins

Abstract

The functionality of caseins in food systems depends on their solubility. The solubilities of whole casein, asl-casein, t3-casein, and dephosphorylated whole casein were measured as the pH was adjusted from 7 to 2 with HCI. When NaCl was added before pH adjustment, solubilities of whole casein at pH 2.5 decreased by 25, 40, 85, and 98% at NaCI concentrations of .01, .05, .1 and .2 M, respectively. Likewise, solubilities of dephosphorylated whole casein decreased by 50%, asl-casein by 30%, and t3-casein by 90% in .1 M NaCl.