Abstract: The Longissimus dorsi muscle of Sunit sheep was selected to analyse changes in the content and activity of adenosine monophosphate-activated protein kinase (AMPK), glycolysis indicators and meat quality indicators during postmortem aging (4 ℃/0, 24, 48, 72 and 96 h), in order to explore the influence of AMPK content and activity on the glycolysis and the aging process after slaughter and determine the best aging time. The results showed that the content and activity of phosphorylated AMPK (p-AMPK) increased firstly and then decreased, reaching the highest value at 24 h. In regard to glycolysis indicators, the pH decreased significantly within 24 h after slaughter; the contents of muscle glycogen and glucose gradually decreased with increasing aging time; the lactic acid content reached its maximum value at 24 h after slaughter. As for meat quality indicators, the shear force reached its maximum value at 24 h, then decreased, and tended to level off after 48 h; the color parameters a* and b* first increased and leveled off after slaughter, while L* value reached its peak at 96 h after slaughter. The number of volatile flavor compounds identified at 0, 24, 48, 72 and 96 h was 29, 30, 41, 40 and 46, respectively. The largest number of aldehydes was found at 48 h, and the aldehydes contributed to improve the overall flavor of sheep meat. In summary, changes in AMPK content and activity at different time points after slaughter will cause changes in glycolysis indicators and consequently affect changes in meat quality indicators. At 48 h after slaughter, mutton has better quality and flavor, and is suitable for processing and eating.

Key words: Sunit sheep; adenosine monophosphate-activated protein kinase; glycolysis; meat quality; flavor