Hygroscopicity and antioxidant activity of whey protein hydrolysate and its ability to improve the water holding capacity of pork patties during freeze−thaw cycles
Lingru Kong, Chunyun Liu, He-xin Tang, Pengjuan Yu, Rongxin Wen, Xinyan Peng, Xinglian Xu, Xiaobo Yu
Abstract
The antioxidant capacity and hygroscopic properties of whey protein hydrolysates and their ability to improve the water holding capacity of pork patties during repeated freeze−thaw cycles (F−T cycles) were investigated in this study. It was found that the optimum hydrolysis time of native whey protein (NWP) was 4 h by hydrolysis degree and iron reduction antioxidant capacity. The separation of 4-h hydrolysate by molecular weight showed that fraction I (F I < 1 kDa) was the most important antioxidant component. Furthermore, it was found that F I had good hygroscopicity, solubility, and stable spatial conformation based on apparent morphology, fourier transform infrared spectroscopy, and circular dichroism spectroscopy. When incorporated into pork patties, adding 15 g of F Ⅰ per 100 g of pork patties (15% F Ⅰ) significantly improved the cooking loss during repeated F−T cycles, and the cooking loss only increased by 18.52 percentage units after 7 F−T cycles. Moreover, F I effectively reduced the destruction of the microstructure of the pork patties. Overall, F Ⅰ is expected to act as an antioxidant and water retaining agent to effectively inhibit food quality deterioration during F−T cycles.