From internal degradation to quality deterioration: Lipid peroxidation-induced protein changes in sea bass (Lateolabrax japonicus) during storage revealed by multi-omics.

This study revealed that during frozen storage of sea bass, reactive carbonyl species from oxidized visceral lipids migrated into the muscle, inducing "lipid-protein co-oxidation." In viscera-containing (CV) samples, myofibrillar protein carbonyl content increased by 108.26%, Ca2+-ATPase activity decreased by 50.9%, and total sulfhydryl content declined by 13.44%. Visceral lipid oxidation also altered free amino acid profiles, elevating bitter-tasting histidine and lysine while reducing sweet proline and glycine, which was consistent with electronic tongue results showing enhanced umami but reduced sweetness. Volatile analysis indicated enriched hydrocarbons and aldehydes in CV group. Proteomics identified 140 differentially expressed proteins, mainly associated with immune and structural functions, with KEGG enrichment highlighting PPAR signaling and immune pathways. Notably, immune proteins exhibited pronounced degradation. This, combined with the breakdown of structural proteins, accelerated muscle quality deterioration.