EFFECT OF PREHEATING AT HIGH-TEMPERATURE UNDER VACUUM ON PHYSICAL-PROPERTIES OF HEAT-INDUCED WHEY-PROTEIN ISOLATE GELS - (STUDIES ON AVAILABLE UTILIZATION OF WHEY PROTEINS .4.)

In this study we investigated the effect of preheating at high tempera ture under vacuum (preheating) on physical properties of heat-induced whey protein isolate (WPI) gels. Weak gels of preheated WPI (120 degre es C for 1 hr) was obtained at low heating temperature (70 degrees C). elastic modulus were formed when preheated WPI was heated at 90 or 10 0 degrees C. behaviour of preheated WPI solution from rheopexy to thix otropy suggested that a precursor of gelation accompanied by reduction of activation energy required for gelation occured in the preheated W PI. The changes in molecular shape and surface charge of protein molec ules associated with conformational changes in preheated WPI were obse rved by HPLC analyses. beta-Lactoglobulin structure was markedly influ enced by preheating of WPI.