牛肉成熟过程中氧化对钙激活酶活性及降解的影响

为了探究牛肉宰后成熟过程中氧化对钙激活酶活性及降解的影响，在牛屠宰后立即取其背最长肌，注射不同浓度氧化剂（0 mmol/L H2O2＋5 mmol/L NaCl ；50 mmol/L H2O2＋5 mmol/L NaCl；200 mmol/L H2O2＋5 mmol/L NaCl；500 mmol/L H2O2＋5 mmol/L NaCl）。真空包装后于4 ℃成熟。分别在0、1、3、7、14 d时取样，通过活性电泳和蛋白免疫印迹进行分析钙激活酶的活性和降解情况。结果表明：在牛肉的宰后成熟过程中，随着氧化程度的提高，μ-钙激活酶活性逐渐减弱，降解程度逐渐增强，而m-钙激活酶活性几乎未发生变化。因此，氧化促进了μ-钙激活酶的降解并抑制了其活性。

Effect of Oxidation on the Activity and Autolysis of Calpain in Beef during Postmortem Ageing

The aim of this study was to explore the effect of oxidation on the activity and autolysis of calpain in beef duringpostmortem ageing. The longissimus dorsi was excised from the carcass immediately after exsanguination. Then oxidizingagent with different concentrations (0 mmol/L H2O2 + 5 mmol/L NaCl; 50 mmol/L H2O2 + 5 mmol/L NaCl; 200 mmol/LH2O2 + 5 mmol/L NaCl; 500 mmol/L H2O2 + 5 mmol/L NaCl) was injected. The samples were vacuum packaged, andstored at 4 ℃ for 0, 1, 3, 7 and 14 days, respectively. Then, casein zymography and Western blotting were used to analyzethe samples. The results showed μ-calpain activity was reduced as a result of enhanced autolysis while m-calpain activityunderwent minor change with increasing oxidation level. Therefore, oxidation can inhibit the activity of μ-calpain andincrease its autolysis during beef postmortem ageing.