Wang Chengcheng, Matarneh Sulaiman K, Gerrard David, Tan Jinglu
Department of Biomedical, Biological and Chemical Engineering, University of Missouri, Columbia, MO, United States of America.
Department of Nutrition, Dietetics and Food Sciences, Utah State University, Logan, UT, United States of America.
Meat Sci. 2022 Jul;189:108828. doi: 10.1016/j.meatsci.2022.108828. Epub 2022 Apr 14.
The roles of energy pathways in postmortem muscles are still debated. In this study, the contributions of different pathways to ATP production and pH variations were analyzed by using a kinetic model based on data from beef longissimus lumborum. Phosphocreatine represents over 92% of the initial ATP production but, after 24 h, glycolysis, phosphocreatine, myokinase reaction, and aerobic respiration contribute, respectively, 89.44%, 5.26%, 4.44%, and 0.86% of the cumulative amount of ATP produced. ATP hydrolysis and glycolysis result in 0.52 and 0.6 units of pH decline, respectively, at 24 h with ATP hydrolysis accounting for most of the early decline. Phosphocreatine, myokinase reaction, and aerobic respiration lead to, respectively, 0.08, 0.07, and 0.004 units of pH increase after 24 h though phosphocreatine is depleted within the first 30 min. Furthermore, electrical stimulation affects pH primarily through ATP hydrolysis and glycolysis. The initial muscle oxygen saturation level and phosphocreatine content affect pH but the influences are small.
能量途径在宰后肌肉中的作用仍存在争议。在本研究中，基于牛肉腰大肌的数据，通过动力学模型分析了不同途径对ATP生成和pH变化的贡献。磷酸肌酸占初始ATP生成量的92%以上，但在24小时后，糖酵解、磷酸肌酸、肌酸激酶反应和有氧呼吸分别占累计ATP生成量的89.44%、5.26%、4.44%和0.86%。在24小时时，ATP水解和糖酵解分别导致pH下降0.52和0.6个单位，其中ATP水解占早期下降的大部分。磷酸肌酸、肌酸激酶反应和有氧呼吸在24小时后分别导致pH升高0.08、0.07和0.004个单位，尽管磷酸肌酸在前30分钟内就已耗尽。此外，电刺激主要通过ATP水解和糖酵解影响pH。初始肌肉氧饱和度水平和磷酸肌酸含量会影响pH，但影响较小。
