Effects of arginine and lysine on quality of shrimp during freeze-thaw cycles

Abstract The objective of this study was to investigate the impact of arginine (Arg) and lysine (Lys) on the quality of shrimp during freeze-thaw (F-T) cycles. The application of Arg and Lys significantly enhanced the a* value of shrimp while effectively suppressing the increase in L* and b* value during the F-T process. Thawing loss, cooking loss, low field-nuclear magnetic resonance, and texture analysis showed that Arg and Lys could significantly reduce water redistribution during the F-T cycle, thereby reducing the effect of F-T process on hardness of shrimp. Hematoxylin and eosin staining also revealed that Arg and Lys were able to inhibit the destruction of muscle tissue by ice crystals. Furthermore, total sulfhydryl content, thiobarbituric acid reactive substances, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis demonstrated that Arg and Lys effectively inhibited oxidation and degradation of lipid and protein on white shrimp during the F-T cycles. Raman spectra showed that Arg and Lys significantly inhibited protein structure changes during F-T cycles. In summary, Arg and Lys can form hydrogen bonds with water molecules through guanidine and amino groups, increasing the binding capacity of water. Arg and Lys reduced ice crystal damage, oxidativemage, and protein structure change during F-T process of white shrimp.