Lipidomics-flavoromics integration in fish muscle: Chemical mechanisms of lipid oxidation, volatile formation, and freshness deterioration during storage and processing.

Fish muscle deteriorates rapidly after harvest because its polyunsaturated lipid-rich membranes, endogenous enzymes, nitrogenous substrates, and hydrated protein matrix remain chemically and microbiologically active. Lipid hydrolysis and oxidation, protein modification, nucleotide degradation, microbial metabolism, and volatile release therefore proceed as interconnected pathways. This review develops a precursor-product-perception framework for integrating lipidomics and flavoromics in fish-quality research. It examines phospholipid remodeling, free-fatty-acid release, hydroperoxide formation and decomposition, reactive carbonyl generation, protein carbonylation, and lipid-protein interactions, together with their roles in forming aldehydes, alcohols, ketones, furans, sulfur compounds, nitrogenous volatiles, and organic acids. The effects of chilling, freezing, freeze-thaw abuse, salting, drying, smoking, thermal processing, packaging, and emerging preservation technologies are evaluated in relation to molecular precursors, microbial activity, protein structure, volatile profiles, and sensory quality. Analytical strategies based on LC-MS lipidomics, GC-MS and GC-IMS flavoromics, microbiomics, protein-oxidation markers, sensory analysis, and chemometrics are compared for biomarker discovery. The review emphasizes that simultaneous measurement alone does not constitute true integration; robust biomarkers require paired sampling, mechanistic precursor-product evidence, targeted confirmation, odor-activity assessment, and external validation across species and storage conditions. This framework supports reliable freshness indicators and mechanism-based quality control for fish and fishery products throughout complex post-harvest commercial supply chains worldwide.