Uncovering quality changes of salted bighead carp fillets during frozen storage: The potential role of time-dependent protein denaturation and oxidation

This study aimed to find the specific relationship between quality traits and myofibrillar proteins (MPs) alteration of salted fish during frozen storage. Protein denaturation and oxidation occurred in frozen fillets, with the denaturation occurring before oxidation. In the pre-phase of storage (0-12 weeks), protein structural changes (secondary structure and surface hydrophobicity) were closely related to the water-holding capacity (WHC) and textural properties of fillets. The MPs oxidation (sulfhydryl loss, carbonyl and Schiff base formation) were dominated and associated with changes in pH, color, WHC, and textural properties during the later stage of frozen storage (12-24 weeks). Besides, the brining at 0.5 M improved the WHC of fillets with less undesirable changes in MPs and quality traits compared to other concentrations. The 12 weeks was an advisable storage time for salted frozen fish and our results might provide an available suggestion for fish preservation in aquatic industry.

Automated summary

This study aimed to investigate the relationship between quality traits and myofibrillar proteins (MPs) alteration during frozen storage of salted fish. Protein denaturation and oxidation occurred in frozen fillets, with denaturation happening first. During the initial phase of storage (0-12 weeks), changes in protein structure were closely related to water-holding capacity (WHC) and texture properties. MPs oxidation (sulfhydryl loss, carbonyl, and Schiff base formation) dominated the later stage of frozen storage (12-24 weeks) and were associated with changes in pH, color, WHC, and texture properties. Brining at 0.5 M improved WHC with fewer undesirable changes in MPs and quality traits compared to other concentrations. A recommended storage time of 12 weeks was suggested for salted frozen fish, providing valuable insights for fish preservation in the aquatic industry.