Comparison of oxidative and techno-functional properties of dark and ordinary muscles in snakehead fish: Insights...

Dark muscle in fish exhibits distinct nutritional, oxidative, and functional characteristics compared to ordinary muscle. This study aimed to elucidate the underlying biochemical variations of oxidative microenvironment in dark and ordinary muscles in snakehead fish (Channa argus) through multi-omics analyses. Dark muscle exhibited a stronger oxidative signature (higher TBARS and protein carbonyls, lower sulfhydryl content), and higher emulsifying activity/stability but lower buffering capacity, reduced foaming capacity and weaker gelation. Dark muscle contained higher levels of crude fat, protein, iron and glutathione, but lower moisture content and pH. Lipidomics revealed enrichment of mitochondria-associated lipid features, particularly cardiolipin and phosphatidylglycerol, together with glycolipids and highly unsaturated triglycerides; proteomics indicated higher abundance of proteins involved in oxidative phosphorylation, fatty-acid β-oxidation and redox/antioxidant defense (e.g., PRDX1, SOD2, MGST3); and metabolomics showed elevated PUFA-derived oxidation products, TCA-cycle intermediates and redox-related cofactors. By integrating lipidomic, proteomic, and metabolomic data, this study captures concordant changes in lipid composition, oxidative metabolism, and redox-related metabolites, thereby providing a more comprehensive explanation for the techno-functional between dark and ordinary muscles and showing that the oxidation-prone biochemical background of dark muscle is associated with enhanced emulsifying properties but reduced gel-forming ability.