The Effect Of AMPK Activity On Postmortem Lamb Glycolysis And Meat Quality

AMPK (AMP-activated protein kinase) activity and glycolysis indexs (muscle glycogen content、lactic acid content、pH value、HK activity) and meat quality indexs (shearing force、color、cooked meat percentage) were measured in different months and parts of postmortem lamb.The same indexs were also measured under the condition of8℃with60%RH of postmortem lamb and after being activated of AMPK activity of postmortem lamb,in order to explore the effect of AMPK activity on postmortem lamb glycolysis and meat quality. The results showed:There were difference of AMPK activity and glycolysis indexs in different months and parts of postmortem lamb. AMPK activity had significant correlation with multiple indexs through correlation analysis. AMPK activity had a significant positive correlation with muscle glycongen content of6months (p<0.05). AMPK activity had a very significant positive correlation with muscle glycogen content of12months and lactic acid content of5months and HK activity of8months (p<0.01).AMPK activity had a significant negative correlation with b*value of6months (p<0.05).It showed that there were correlation between AMPK activity and postmortem lamb glycolysis and meat quality. Difference of AMPK and glycolysis may lead to the difference of meat quality.AMPK activity of postmortem lamb raise rapidly,the maximum value emerged at1h postmortem, then decreased. HK activity had the same tendency. Meanwhile, muscle glycogen decomposed and lactic acid produced and pH value became lower, which showed that change of the breath way activated AMPK and AMPK may affect glycolysis process through glycolytic key enzyme—HK.When pH was close to the limit pH, rigidity was close to the maximum, shearing force was the largest, tenderness was the worst, cooked meat percentage was the lowest. In the meantime, when pH was at isoelectric point, water-holding capacity of meat decreased, surface water seepage increased so that it led to bright color.When AMPK activity was activated by metformin, HK activity was enhanced, both muscle glycogen decomposition and lactic acid accumulation were accelerated, pH drop speed was accelerated, too. Glycolysis process of postmortem lamb was promoted after being activated of AMPK activity. At the same time, shearing force increased, the tenderness decreased a little, L*value increased, a*value and b*value decreased, postmortem lamb’s color was poor relatively.Change of AMPK activity had effect on glycolysis and meat quality. After being activated of AMPK activity, glycolytic key enzyme—HK activity was enhanced, glycolysis process was accelerated and meat quality had been changed.