不同电刺激时间对牦牛肉在成熟过程中品质变化的影响

Effect of different time electrical stimulation on quality of yak during aging

研究不同电刺激时间对宰后牦牛肌纤维结构及食用品质的影响。选择20头甘南黑牦牛每5头一组按实验设计进行电刺激ES＆C（电压21V，额定功率50w，时间72、90、108s）和常规冷却排酸NC（0-4℃，风速0．5m／s）处理，在成熟过程中的0、24、72、120、168、216h测定牦牛肉的剪切力、糖原含量和肌纤维超微结构，在宰后24h内测定牦牛胴体的温度和pH。结果显示：电刺激处理可以加快牦牛肉pH的降低，有效防止冷收缩的发生；ES＆C的剪切力在宰后成熟过程中均小于NC，在最后216h，ES＆C108s的剪切力值极显著的高于ES＆C72s和90s（P〈0．01），其剪切力值分别比Es＆C72s和90s高7．77％和14．29％；加快了糖原的降解，Es＆C的糖原含量分别比NC低37_45％、48．52％、52．58％、60．43％、58．79％、50．48％；电刺激破坏了牦牛肉肌纤维结构，出现挛缩带。结论：电刺激处理能显著改善牦牛肉嫩度。

To study the different time effect of electrical stimulation on myofibrillar microstructure and eating quality of yak at postmortem.This article studied the electrical stimulation （21V, 50W, ES72,90,108s）and normal chilling （ NC 0~4~C,wind speed 0.5 m/s） ,then determine the shear force, glycogen content and myofibrillar microstructure at 0,24,72,120,168,216h during aging.And determine the pH and temperature of yak in 24h after postermortem. The results showed that electrical stimulation increased the rate of pH and temperature drop,and could prevent the cold shorten effectively. At the time postmortem, the shear force of ES＆C was lower than NC. At 216h of the postmortem,the shear force of ES＆CI08s were higher than ES＆C72s and ES＆C90s （p 〈 0.01 ）, were 7.77% and 14.29% higher than ES＆C72s and ES＆Cg0s.The degradation of glycogen was increased,the glycogen of ES＆C were 37.45%, 48.52%, 52.58%, 60.43%, 58.79%, 50.48% lower than NC. Electrical stimulation destroied the myofibrillar microstructure. Conclusion.Electrical stimulation could shorten the aging time of yak and improve the tenderness.