Uncovering the Contribution of Protein Degradation and Amino Acids Metabolism to the Odor of Tilapia (Oreochromis mossambicus) During Cold Storage: Based on the Amino Acids Metabolomics Analysis Via LC–MS

Protein degradation is a common occurrence in tilapia during the refrigeration process, leading to the generation of unpleasant odor and impacting overall flavor and quality. This study characterized the protein degradation of tilapia during cold storage and utilized amino acids metabolomics analysis to identify metabolic pathways and differential metabolites associated with odor formation and changes. The protein degradation of tilapia during cold storage was characterized through analysis of trichloroacetic acid (TCA) soluble peptides, protein concentration, electrophoresis patterns, protein secondary and tertiary structures, as well as microscopic structures. The characterization of these indicators revealed an obvious protein degradation and structural disruption of tilapia during cold storage. Changes in the types and contents of free amino acids (FAAs) were discussed. Protein degradation produced a large number of FAAs, with Lys contributing the most to flavor changes. By employing amino acids metabolomics analysis, primary and secondary differential metabolites were selected, along with differential metabolic pathways based on amino acids metabolism. And the related amino acid metabolic network was constructed. This study contributes to revealing the impact of amino acids metabolism on odor formation and changes, providing further insights for the research and regulation of odor.