Investigation of the protective effects of antifreeze peptides from grass carp skin on frozen surimi

This study investigated the protective effects of antifreeze peptides (CSAFPs), derived from enzymatic hydrolysis of grass carp skin, on frozen surimi. CSAFPs were incorporated into surimi at concentrations ranging from 0.01% to 0.5%, and their influence on the myofibrillar protein (MP) properties and textural characteristics of surimi gel during frozen storage was assessed. The results showed that CSAFPs enhanced the whiteness of surimi gel and alleviated the decline in salt-soluble protein content, sulfhydryl group levels, and Ca2+-ATPase activity. Furthermore, CSAFPs inhibited the increase in carbonyl content and surface hydrophobicity, suggesting their ability to minimize cryodamage to MP by reducing oxidation and denaturation, thereby preserving the spatial structure of MP. The cryoprotective effects of CSAFPs were dose-dependent, with the highest concentration (0.5%) achieving similar efficacy to the commercial antifreeze formulation (4% sucrose + 4% sorbitol). However, CSAFPs at concentrations of 0.1% or higher significantly reduced water-holding capacity, hardness, and recoverable springiness, while delaying the deterioration of these parameters during frozen storage. The microstructural analysis further corroborated these findings. In conclusion, CSAFPs demonstrate promising antifreeze effects in frozen surimi, although their impact on textural properties highlights the need for further research into the underlying mechanisms.