Dynamic Metabolic Changes During Postmortem Aging of Yili Horsemeat Revealed by Untargeted Metabolomics

Postmortem aging is a crucial process for improving meat quality; however, the metabolic mechanisms underlying the postmortem maturation of Yili horsemeat remain unclear. In this study, untargeted metabolomics was employed to investigate the dynamic changes in metabolites during postmortem aging of Yili horse longissimus dorsi muscle. Samples from six Yili horses were subjected to aging at 4 °C for 0, 14, and 28 days. Intramuscular Environment and metabolic profiles were analyzed using UHPLC-QTOF-MS. Results showed that meat pH initially decreased and then increased over the aging period (p < 0.05), whereas muscle fiber diameter and cross-sectional area gradually declined (p < 0.05). Metabolomic analysis revealed significant differences in metabolic profiles among different aging stages. KEGG pathway enrichment analysis indicated that the differentially expressed metabolites (DEMs) were predominantly involved in purine metabolism, nucleotide metabolism, and amino acid biosynthesis pathways. Notably, the degradation of AMP and IMP into inosine and hypoxanthine and the accumulation of free amino acids such as tryptophan and phenylalanine were closely associated with the development of umami taste and overall flavor of horsemeat. These findings elucidate the key metabolic pathways regulating postmortem meat quality in Yili horses and provide a theoretical basis for its production and application.