Protective Effect of L-Lysine on Silver Carp Surimi During Freezing Storage: Gel Quality Improvement and Physicochemical Properties

Abstract

This study aimed to investigate the protective effect of 0.1%, 0.2%, 0.3%, 0.4% and 0.5% L-lysine (Lys) on frozen silver carp surimi by evaluating gel strength, water holding capacity and protein structure, and further to explore the mechanism of Lys delayed the quality deterioration of frozen silver carp surimi. Among these concentrations, 0.4% Lys exhibited optimal freezing protection for silver carp surimi. Compared with control groups and commercial antifreeze agents, Lys-treated frozen surimi demonstrated superior gel strength, water holding capacity, and whiteness after 30 d of frozen storage while exhibiting a compact gel network. The mechanism of action was mainly due to the rise of pH value in the freezing process to form myofibrillar protein aggregates that exhibited high resistance to degradation, which prevented the exposure of hydrophobic amino acids and the oxidation of sulfhydryl groups, thus affecting the effective cross-linking of proteins during the gelation process and forming a smoother and denser fiber structure. The findings demonstrated the potential of Lys as a cryoprotectant, thereby establishing a theoretical foundation for the development of eco-friendly alternatives to antifreeze and high-gel frozen surimi products.

Keywords: L-lysine, Silver carp surimi, Frozen storage, Gel properties