Effects Of CaCl₂ On Meat Quality And Energy Metabolism Of Different Varieties Beef During Postmortem Aging

Beef is rich in nutrition,but its tenderness is poor,which affects its edible and processing quality.In order to improve tenderness,the study was designed to compare the changes of meat quality of post-mortem yak meat and cattle longissimus dorsi?LD?,which were injected with 200mM CaCl₂?10%of meat weight?.The effects of CaC1₂ on meat quality,energy metabolism and partial proteolytic enzyme activity were analyzed.It provided a basis for improving tenderness and further studying the mechanism of tenderness.The main conclusions are as follows:1.Injection of CaCl₂ solution affected meat quality of beef during postmortem aging.The L^*value,b^*value,and MMb content in the CaCl₂ group were lower than those in the non-CaCl₂ group,and the MFI,a^*,and TMb contents were higher in the CaCl₂ group than in the non-CaCl2 group.The pressure loss and cooking loss in CaCl₂ group at the early stage of aging?6 h to 12 h?were significantly lower than those in the non-CaCl₂ group.The shear stress,hardness,chewiness and cohesion of CaCl₂ group were significantly lower than those of non-CaCl₂ group in the middle and later stages of aging?72 h to 168 h??p<0.05?.The blank group shear force value of yak meat reached its maximum value at 72 h,and it reached the acceptance level of human consumption at 168 h,and the CaCl₂ group reached the acceptance level within 72 h.The blank group shear force value of cattle meat reached its maximum value at 120 h,and it reached the acceptance level of human consumption at 168 h,and the CaCl₂ group reached the acceptance level at 24 h.CaCl₂ treatment can accelerate the rate of aging of beef,and has a greater effect on the yak meat than cattle.2.Injecting CaCl₂ solution had effects on energy metabolites and energy metabolism enzymes of beef during postmortem aging.The injection of CaCl₂ solution significantly accelerated the rate of decline of pH value,muscle glycogen degradation,lactate production,and ATP consumption in the early stage of aging in beef?6 h⁷2 h??p<0.05?,and it significantly increased the activity of LDH and Ca²⁺-ATPase at the early stage of aging?6h¹2 h??p<0.05?.The pH value and muscle glycogen content of the Ca Cl₂ group was the lowest,and lactic acid content was the highest at 72 h in yak meat;and the pH of the blank group reached the minimum value at 72 h which was higher than that of CaCl₂ group.The lowest pH value,lowest muscle glycogen content and highest lactic acid content were observed in the blank cattle meat CaCl₂ group at 72 h of aging;and the blank group had the lowest pH value at 120 h.The CaCl₂ treatment accelerates the energy metabolism of the longissimus muscle in beef during postmortem aging.The effect of CaCl₂ treatment on the energy metabolism of yak meat is greater than that of cattle.3.Injecting CaCl₂ solution affected the activities of calpain and caspase of beef during postmortem aging.CaCl₂ treatment increased the activity of?-calpain,m-calpain and caspase-9,3 in the early stage of aging.The activity of?-calpain in the CaCl₂ group of yak was highest at the 6 h,while the activity of the control group was lower than that of CaCl₂group in yak meat duringpost mortem aging.In the CaCl₂ group,m-calpain activity remained active for 72 h,while no significant change in m-calpain activity was observed in the non-CaCl₂ group.CaCl₂ group caspase-9,3 activity reached the maximum at 6 h and 12 h,non-CaCl2 group corresponding time is 12 h and 24 h.The activity of?-calpain in the CaCl₂group of cattle was the highest at the 12 h.The activity of m-calpain in the CaCl₂ group remained active for 120 h.The activity of caspase-9 and 3 of the CaCl₂ group was the highest at 12 h and 24 h,respectively,and the corresponding time in the non-CaCl₂ group was 24 h and 24 h.CaCl₂ treatment activates the calcium-activating enzyme activity and apoptotic enzymatic activity of beef,accelerates the process of apoptosis.And the effects of CaCl₂ in activates the calcium-activating enzyme and apoptotic enzyme for yak meat were more than cattle.