Effect of whey protein hydrolysate on the structural and functional stability of surimi myofibrillar protein gels during freeze-thaw cycles

This study investigates the effects of varying concentrations of whey protein hydrolysate (WPH) (5 %, 10 %, 15 %) on surimi myofibrillar protein gels subjected to freeze-thaw (FT) cycles. With an increase in the number of FT cycles, there was a decrease in both ionic and hydrogen bonding, resulting in reduced chewiness and elasticity. At the same time, hydrophobic interactions were strengthened, leading to disruptions in protein secondary structures. In contrast, the addition of WPH significantly improved and stabilized the gels' intermolecular interactions and textural properties, particularly at the 15 % concentration, which demonstrated superior effects compared to both the untreated control and the positive control treated with 0.02 % butylated hydroxyanisole (BHA) (P < 0.05). Furthermore, 15 % WPH effectively preserved the gel's secondary structure and water-holding capacity, significantly outperforming the 0.02 % BHA positive control group (P < 0.05). These findings highlight the potential of WPH to enhance intermolecular interactions and preserve the structural integrity of myofibrillar protein gels during FT cycles, indicating its promising application in food science.