PREPARATION AND PROPERTIES OF SALT-INDUCE D GEL OF WHEY-PROTEIN

Salt-induced gelation of partially heat-denatured whey protein isolate (WPI) solution and the theological properties of the resultant gels w ere investigated. A 10% WPI solution, pH 7.0, was heated at 80 degrees C for 30 min, and then cooled to 5 degrees C for obtaining the partia lly heat-denatured WPI solution. The solution was incubated at 20 degr ees C in the presence of salts such as NaCl and CaCl2. During incubati on, the solution turned to homogeneous gel with increasing viscosity. Gel strength was dependent on heating temperature of the WPI solution and salt concentration. Electron microscopy showed the presence of sho rt-chained soluble aggregates in the partially heat-denatured WPI solu tion, and the gelation of the aggregates initiated by the addition of NaCl at 20 degrees C. The network structure of salt-induced gel was to some extent coarser than that of acid-induced gel. It was indicated t hat the formation of the soluble aggregates by healing and the interac tion between the soluble aggregates by salt were related to salt-induc ed gelation.