Changes in postmortem metabolites profile of atypical and typical DFD beef

This study explored the changes in postmortem metabolites of atypical and typical DFD beef using UHPLC-Q-TOF/MS. The longissimus thoracis muscles were categorized into normal, atypical DFD and typical DFD groups. The L^⁎, a^⁎, b^⁎, glycogen and lactic acid contents were lower (P < 0.05) in typical DFD than normal beef. A total of 240 compounds were significantly different among groups. Levels of glycerol-3-phosphate, d-ribose-5-phosphate, d-glucose-6-phosphate, d-fructose-6-phosphate, alpha-d-glucose-1-phosphate and dihydroxyacetone phosphate were higher in atypical DFD than those in the normal and typical DFD beef and the contents of 9 amino acids were elevated in typical DFD. KEGG analysis showed that metabolomic changes were primarily related with ATP-binding cassette transporters, metabolism of purine, central carbon, glycine, serine and threonine, biosynthesis of aminoacyl-tRNA, digestion and absorption of proteins, metabolism of amino sugar and nucleotide sugar, pyrimidine, bile secretion and galactose. In conclusion, development of atypical and typical DFD meat results in differences at level of postmortem metabolite concentrations of different metabolic pathways.