Effect of Whey Protein Isolate on Ice Recrystallization Characteristics in Whey Protein Isolate/κ-Carrageenan Matrix

cryoprotectant,This study was carried out to investigate the physical and thermal properties of κ-carrageenan (κ-car) gel added whey protein isolate (WPI) as a cryoprotectant. The concentration of κ carrageenan was fixed at 0.2 wt%. The mean ice crystal size of the WPI/κ-car was decreased according to increasing whey protein isolate concentration. The temperature of gel-sol (Tg-s) and sol-gel (Ts-g) transition of WPI/κ-car maxtrix was represented in the order of 3.0, 0.2, 5.0 and 1.0 wt%. In addition, the transition temperature of gel-sol of WPI in sucrose solution were showed in order of 1.0, 5.0, 0.2 and 3.0 wt% depending on whey protein isolate concentration. The shape of ice crystal was divided largely into two types, round and rectangular form. 1.0 wt% WPI/κ-car matrix at pH 7 and 9 showed minute and rectangular formation of ice crystals and whey protein isolate in sucrose solution at a concentration of 1.0 wt% WPI/κ car matrix at pH 3 and 5 showed relatively large size and round ice crystals. The ice recrystallization characteristics and cryprotective effect of κ-carrageenan changed through the addition of different concentrations of whey protein isolate. It seems that the conformational changes induced interactions between whey protein isolate and κ-carrageenan affected ice recrystallization. ice recrystallization, κ-carrageenan, whey protein isolate