AMPK活化调控的能量代谢对宰后牦牛肉肉色稳定性影响的研究

Effect of Energy Metabolism Regulated by AMPK Activation on Meat Color Stability of Postslaughter Yak Meat

为探究牦牛肉在宰后成熟过程中单磷酸腺苷激活蛋白激酶(AMPK)活化调控的能量代谢对肉色稳定性的影响,本实验以牦牛背最长肌为研究对象,使用AMPK激活剂(AICAR)和抑制剂(Compound C)对其进行处理,并置于4℃下成熟,在相应的成熟时间点对AMPK活性、肉色及能量代谢相关指标进行测定,并进行肉色和能量代谢指标相关性分析。结果表明:成熟至12 h,与对照组相比,AICAR组AMPK活力提高了13.17%,而抑制组降低了9.03%,表明AICAR对AMPK活性有激活作用,而Compound C对AMPK活性有明显的抑制作用。随着成熟时间的延长,三者的L^(*)值、a^(*)值和己糖激酶的活性均呈先上升后下降趋势,b^(*)值、H^(*)值、乳酸含量均呈逐渐上升的趋势,其中L^(*)值、b^(*)值和H^(*)值始终为AICAR组>对照组>Compound C组,a^(*)值始终为AICAR组<对照组<Compound C组。在成熟期间三组的pH、肌酸激酶活性与糖原合成酶活性则先下降后缓慢上升,总肌红蛋白(TMb)含量、氧合肌红蛋白(OMb)含量、高铁肌红蛋白还原酶(MetMbR)、乳酸脱氢酶(LDH)活性和还原型辅酶Ⅰ(NADH)含量呈下降趋势,高铁肌红蛋白(MMb%)呈上升趋势,AICAR组、Compound C组和对照组成熟至168 h时,其总肌红蛋白(TMb)含量与6 h相比,分别下降了34.52%、31.63%和33.67%,OMb含量分别降低了41.38%、40.40%和40.57%,MetMbR活性仅为6 h的39.74%、42.72%和41.41%,而MMb含量则分别上升了310%、291%和309%。从趋势上来看,AMPK活性的抑制能够使NADH含量、糖原含量、糖原合成酶活性、肌酸激酶活性以及LDH活性升高,使己糖激酶活性以及乳酸含量降低。相关性分析表明,NADH含量、糖原含量、LDH活性、己糖激酶活性的上升以及乳酸含量、肌酸激酶活性、糖原合成酶活性的下降均能在一定程度上提高肉色的稳定性。而AMPK活性的抑制能够增加NADH的含量、肌酸激酶活性以及糖原合成酶活性,同时降低乳酸含量及己糖激酶的活性。综上,AMPK活性的抑制有利于牦牛背最长肌在成熟期间肉色的稳定,而在牦牛背最长肌成熟过程中,AMPK活性的抑制通过增加NADH的含量、糖原含量、LDH活性和降低乳酸含量来维持肉色的稳定性。

In order to explore the effect of AMPK activation-regulated energy metabolism on meat color stability of yak meat during the maturation of yak meat,this experiment took the yak longissimus dorsi muscle as the research object,treated it with AMPK activator(AICAR)and inhibitor(Compound C),and placed it at 4℃for maturation.AMPK activity,flesh color and energy metabolism related indexes were measured at the corresponding maturation time point,and the correlation analysis between flesh color and energy metabolism indexes was performed.The results showed that compared with the control group,the AMPK activity of the AICAR group increased by 13.17%,while the inhibitory group decreased 2021 by 9.03%after 12 h of maturation,indicating that AICAR had an activating effect on AMPK activity,while Compound C had a significant inhibitory effect on AMPK activity effect.With the extension of maturity time,the L^(*)value,a^(*)value and the activity of hexokinase all showed a trend of increasing first and then decreasing.The b^(*)value,H^(*)value,and lactic acid content all showed a gradual upward trends,among which L^(*),b^(*)and H^(*)were always AICAR group>control group>compound C group,and a^(*)value was always AICAR group<control group<compound C group.During the maturation period,the pH value,creatine kinase activity and glycogen synthase activity of the three groups decreased first and then slowly increased.TMb content,OMb content,MetMbR activity glycogen content,LDH activity and NADH content showed a downward trends,while MMb content increased.When the AICAR group,compound C group and control group matured to 168 hours,their TMb content decreased by 34.52%,31.63%,and 33.67%,respectively,and OMb content decreased by 41.38%,40.40%,and 40.57%,respectively,MetMbR activity was only 39.74%,42.72%and 41.41%of 6 h,while MMb content increased by 310%,291%and 309%,respectively.From a trend point of view,the inhibition of AMPK activity could increase make NADH content,glycogen content,glycogen synthase activity,creatine kinase activity and LDH activity,and reduce hexokinase activity and lactic acid content.Correlation analysis showed that the increasing of NADH content,glycogen content,LDH activity,hexokinase activity and the decreasing of lactic acid content,creatine kinase activity,glycogen synthase activity could improve the stability of flesh color to a certain extent.Inhibition of AMPK activity could increase NADH content,creatine kinase activity and glycogen synthase activity,while reduc lactic acid content and hexokinase activity.In summary,the inhibition of AMPK activity was conducive to beneficial to the stability of the flesh color of the yak longissimus dorsi muscle during maturation.During the maturation of the yak longissimus dorsi muscle,the inhibition of AMPK activity could increase NADH content,glycogen content,LDH activity and reduce lactic acid to maintain the stability of flesh color.