Study on the mechanism of protein hydrolysate delaying quality deterioration of frozen surimi

The surimi processing industry generates a large number of underutilized by-products. The aim of this study was to evaluate the protein oxidation, protein degradation, and gel property of surimi during frozen storage to investigate the mechanism of cryoprotective effects of surimi by-product protein hydrolysates on surimi. The results showed that compared with Control and Cryoprotectant surimi, surimi by-product protein hydrolysates groups had lower thiobarbituric acid content, carbonyl content and surface hydrophobicity, higher Ca2+-ATPase activity, total sulfhydryl groups and salt-soluble proteins (P < 0.05), which significantly delayed the freezing denaturation and oxidation rate of surimi myofibrillar protein during frozen storage. Aggregation of surimi proteins occurred during frozen storage, and surimi by-product protein hydrolysates could inhibit the degradation of myofibrillar protein and effectively induce protein cross-linking, which led to the formation of a denser gel network in surimi. In summary, surimi by-product protein hydrolysates was expected to be a natural and green cryoprotectant and gel texture enhancer in surimi.