Nontargeted metabolomics reveals dynamic changes in the quality of fresh yak meat during ice-temperature preservation

Fresh yak meat is nutritious but susceptible to deterioration. The development of effective preservation techniques for fresh yak meat is highly important. In this study, the quality changes of fresh yak meat during icetemperature (-1 degrees C) preservation and refrigerated (4 degrees C) preservation were evaluated. Within 15 days of preservation, the quality indicators of the yak meat preserved at ice temperature did not exceed the national standards, but the shelf life of the refrigerated meat was only 5 days. The TBARS, TVB-N, total viable counts of ice-temperature-treated meat were significantly lower than those of refrigerated meat. The dynamic changes in the metabolome of ice-temperature preservation meat were also investigated. A total of 2954 metabolites were annotated, and differentially regulated metabolites were mainly concentrated in amino acids and their metabolites, fatty acyls, benzene and its derivatives, aldehydes, ketones and esters, organic acids and its derivatives, etc. The significantly differentially regulated metabolites were mainly involved in protein and lipid oxidation. KEGG enrichment analysis revealed that the major metabolic processes involved in the deterioration of yak meat during ice-temperature preservation were purine metabolism, ABC transporters, biosynthesis of cofactors, biosynthesis of amino acids, nucleotide metabolism, glycerophospholipid metabolism, linoleic acid metabolism, and phenylalanine metabolism.