Correlation Analysis between Calpains and Tenderness Indexes during Postmortem Aging of Yak Meat
Longissimus dorsi muscles of ten yaks from the south part of Gansu province were tested for myofibril fragmentation index (MFI),shear force,muscle fiber diameter and the activities of calpains (μ-calpain,m-calpain and calpastatin) during 8 d of postmortem aging.Furthermore,the calpain activities were analyzed for correlation with MFI,shear force and muscle fiber diameter.The results showed that each calpain activity was positively correlated with shear force and muscle fiber diameter,but negatively correlated with MFI; a significant correlation with MFI was observed for μ-calpain and calpastatin (P<0.05).Therefore,the changes in calpain activity may cause in the increase in MFI,weaken myofibrils and tenderize meat andμ-calpain seems to mainly contribute to tenderizing yak meat.