The study investigated the glycolysis pathway mediated by hypoxia-inducible factor-1 alpha (HIF-1 alpha) and the mechanism of its regulation. The results indicated that HIF-1 alpha expression initially increased before subsequently decreasing with aging time during postmortem (p <.01). Glucose transporter-1 (GLUT-1), lactate dehydrogenase (LDH), and hexokinase (HK) displayed a similar trend with aging time (p <.01) while pyruvate dehydrogenase kinase 1 (PDK-1) increased gradually within the first 12 hr before decreasing at 24-120hr. However, after treatment with a HIF-1 alpha inhibitor, no significant differences were observed in the mitochondrial morphology. Furthermore, lactate content decreased, along with LDH, HK, and FOF1-ATP activities as well as GLUT-1 and PDK-1 expression (p <.01). The shear force for all groups also increased during postmortem aging (p < .01), with that of the controls being significantly higher compared with the treatment groups (p <.01). These findings confirmed that, after slaughter, the hypoxic environment within the muscles provided essential conditions for HIF-1 alpha expression, which, in turn, activated the glycolysis pathway by mediating changes in the activities of glycolytic enzymes and mitochondrial function. Moreover, in accelerating glycolysis rate, the expression of HIF-1 alpha further played a negative role in meat tenderization during postmortem aging. This, it was concluded that HIF-1 alpha expression plays a significant role in postmortem yak meat tenderization by regulating the glycolysis pathway. Pratical applications: While converting muscle into meat through hypoxic glycolysis during postmortem aging is undeniable, the biochemical mechanism of this process mediated remains quite obscure. However, the meat quality difference which impact muscle regulation mechanism during postmortem aging has not been reported. The study investigated the HIF-1 alpha played a major role in both the glycolytic pathway and as well as meat tenderness during the postmortem aging of yak meat. The glycolysis pathway is mediated by hypoxia-inducible factor-1 alpha (HIF-1 alpha), the mechanism of its regulation, and meat tenderness during the postmortem aging of yak meat.
