Objective The aim of the present study is to explore the effect of salt marination on the protein and flavor characteristics of Sebastes schlegelii fillets.

Methods Drip loss, ATP and its related compounds, free amino acids, Ca²⁺-ATPase activity, and pH were used as indicators to study the changes in protein and flavor characteristics after marination with 5% salt and different proportions of salt (0%, 1%, 2%, and 5%) following de-blooding treatment.

Results The results demonstrated that the de-blooding treatment effectively reduced drip loss during marination and cold storage, with the de-blooding group exhibiting a drip loss rate of 13.20%±0.65% after 48 hours, lower than the non-de-blooding group (17.32%±0.49%). Furthermore, de-blooding significantly inhibited ATP degradation, as evidenced by the IMP content in the de-blooding group (7.03±1.72) μmol/g compared to the non-de-blooding group (4.78±0.82 ) μmol/g. The salt content in fish meat tended to increase with higher marination salt ratios. Additionally, myofibrillar protein Ca²⁺-ATPase activity decreased progressively during marination with varying salt ratios, measuring 8.4×10⁻³, 6.7×10⁻³, 5.5×10⁻³, and 5.3×10⁻³ μmol/(mg·min) for 0%, 1%, 2%, and 5% salt respectively after 24 hours. The highest IMP content (7.70 μmol/g) occurred in fish marinated with 1% salt, decreasing to (2.64±1.10) μmol/g after 48 hours of cold storage. Marination also enhanced the presence of flavor-contributing amino acids; glutamic acid content rose from (0.10±0.01) mg/g in 0% salt marination to approximately (0.18±0.01) mg/g, (0.20±0.05) mg/g, and (0.24±0.04) mg/g in 1%, 2%, and 5% salt marination respectively.

Conclusion In conclusion, the de-blooding treatment effectively reduced the drip loss rate of marinated fish fillets and significantly inhibited the degradation of IMP, glycine, and alanine. Marinating the fish with a 1% salt concentration resulted in higher IMP content retention, while the glutamate levels in the fish remained consistently elevated.