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

## TL;DR

This study uses untargeted metabolomics to track how Yili horsemeat changes during postmortem aging, identifying key metabolic pathways that affect meat quality and flavor.

## Contribution

The study reveals novel metabolic pathways and flavor-related compounds in postmortem Yili horsemeat aging using untargeted metabolomics.

## Key findings

- Metabolic profiles changed significantly during postmortem aging, with key roles for purine and amino acid metabolism.
- Degradation of AMP/IMP and accumulation of tryptophan/phenylalanine enhance umami flavor in aged horsemeat.
- Muscle fiber diameter and area decreased over aging, while pH showed a biphasic trend.

## Abstract

This study explored metabolic changes in Yili horse longissimus dorsi muscle during 0, 14, and 28 days of postmortem aging at 4 °C via untargeted metabolomics. Results showed pH first decreased then increased, while muscle fiber diameter and area declined. Metabolomic analysis identified distinct metabolic profiles across stages, with differential metabolites enriched in purine metabolism, nucleotide metabolism, and amino acid biosynthesis. AMP/IMP degradation into inosine/hypoxanthine and accumulation of tryptophan/phenylalanine enhanced umami and flavor. The findings clarify key metabolic pathways regulating Yili horsemeat quality postmortem, providing a theoretical basis for production and application.

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.