Effect of different frozen storage conditions on Yuba quality

Yuba is a vegetable protein made from soya beans, with high-protein and high-lipid characteristics. This study investigated the quality change and deterioration mechanism of Yuba during frozen storage at different temperatures and times. The significant decrease in the water holding capacity (WHC) of Yuba occurred during frozen storage. And the sulfhydryl groups within the Yuba protein (YP) were broken with more disorder structure. The frozen storage refolds the polypeptide chains into proteins aggregates. Yuba occurred ripening at -3 °C obviously compared to -20 °C and -40 °C after 21 d of frozen storage. The quality change of Yuba was dominated by protein denaturation and mechanical damage by ice crystals in the early stage. The sharp increase in protein and lipid oxidation of Yuba at the later stages suggests that higher lipid oxidation reactions are promoted along with protein oxidation. Synergistic effects of lipid and protein oxidation in the later stages exacerbated the degradation of Yuba quality. The high-lipid content makes Yuba more susceptible to quality deterioration during frozen storage compared to other high-protein foods. This study provides a reference for the preservation of high-lipid and high-protein foods.