Effect of #gamma#-irradiation on the physicochemical properties of soy protein isolate and whey protein concentrate

摘要

Effect of #gamma#-irradiation on the SDS-PAGE pattern, secondary structure content, the solubility of commercial soy protein isolate (SPI) and whey protein concentrate (WPC) was investigated. The change in the subunit molecular weight of SPI and WPC irradiated in aqueous solution or dried state was studied using SDSPAGE. The SDS-PAGE pattern of SPI irradiated in aqueous solution revealed the fragmentation and aggregation of the subunit protein. For WPC irradiated in aqueous solution, fragmentation of the subunit protein up to 10 kGy was observed. In contrast, #gamma#-irradiation of SPI and WPC in dried state did not cause any significant changes in the SDS-PAGE pattern. The change in the secondary structure of irradiated SPI and WPC solution was studied using circular dichroism. The aperiodic structure content of SPI and WPC solution increased at higher irradiation doses, which suggests that #gamma#-irradiation caused the disruption of the ordered structure of SPI and WPC solution. Gamma-irradiation also caused the change in solubility of SPI and WPC in dried state.