电刺激对宰后牦牛肉ATP、calpain活力和细胞骨架蛋白降解的影响

摘要

The early electrical stimulation (voltage 21V,rated power 50 W )on the ATP and calpain activities and myofibrillar proteins degradation of yak meat and its meat tenderization mechanism were studied.Twenty-four Gannan yaks were divided into two groups,one group was treated with electrical stimulation (voltage 21 V,power 50 W,time 90 s)(ES),while the other group was treated with conven-tional chilling (0~4 ℃、wind speed 0.5 m/s)(NES),the ATP,calpain activity,glycogen,shear force and myofibrillar degradation of longissimus muscle from two groups were determined at 0,24 and 72 h.The re-sults showed that electrical stimulation could accelerate the process of glycolysis,the ATP in ES group de-creased 14.97% at 72 h after butchered,which was 6.59% higher than that of NES group.Electrical stimu-lation significantly increased the decreasing rate of the ATP,but increased the m-calpain andμ-calpain ac-tivities by 0.318 U/mL and 0.31 U/mL respectively.At the same time,electrical stimulation reduced the shear force value (P<0.01),accelerated the degradation of desmin and troponin-T,induced the aging of yak meat ,and cut down the aging time.%为了研究低压电刺对牦牛肉 ATP、Calpain活力和细胞骨架蛋白降解的影响及其嫩化机理,将24头甘南牦牛随机分为2组,每组12头,屠宰,按试验设计对宰后牦牛胴体进行电刺激(ES)(输出电压21 V、功率50 W、时间90 s)和常规冷却排酸 NES(0~4℃、风速0.5 m/s)处理,并于0、24、72 h测定牦牛背最长肌的 ATP、calpain活力、糖原、剪切力值和细胞骨架蛋白降解情况.结果表明：宰后72 h ATP 下降了14.97%,较 NES 组下降幅度达6.59%,ES显著提高了ATP的下降速率；宰后0 h,ES组糖原较NES组低12.46%,加快了糖酵解速率；ES组在宰后0 h m-calpain和μ-calpain较 NES组活力分别提高了0.318 U/mL 和0.31 U/mL,同时提高了 m-calpain和μ-calpain活力,过早激活了μ-calpain；ATP与m-calpain有极显著的负相关性(P<0.01),而μ-calpain与糖原含量、剪切力三者相互之间有极显著的正相关性(P<0.01)；低压电刺激极显著提高牦牛肉最终嫩度(P<0.01)；电刺激在速度和数量上显著加速了Desmin和Troponin-T的降解,加快了牦牛肉成熟,缩短了成熟时间.