Effect Of Low Voltage Electrical Stimulation On Yak Meat Quality In Aging

Tenderness is the most important quality of meat quality, is also the quality that customer concern about. The tenderness affects the meat quality, directly determine the values of their goods. However, yak because of its unique geographical environment, result in the muscle fibers is thick, which can not be accepted by consumers, impact on its domestic sales and export seriously. Hinding the development of yak industry.16 yaks were selected and divided into 4 treatment groups randomly(3 groups were electrical stimulation, 1 group was normal chilling). The low voltage electrical stimulation was used after slaughter(21V, 50 W, time 72, 90, 108s), then carcasses were splited. Bring All the carcasses into aging process(0~4 ℃, wind speed 0.5m/s, humidity 80%). Determinate the pH, temperature, glycogen content, color, shear force, driping loss, MFI, TPA, muscle ultrastructure, protein degradation during chilling. The results as follows:The electrical stimulation increased the rate of p H drop. The pH of ES&C 108 s droped fastest, was 2.98, 2.16, 5.23 times of other groups;The electrical stimulation increased the rate of glycolysis. At the end of aging the glycogen content of electrical stimulation treatment was lower than NC significantly(P<0.01). But there were no difference among the treatment of electrical stimulation(P>0.05). It can also increased the rate of pH drop, at 24 h after slaughter the pH of electrical stimulation treatment almost drop to minimum;The electrical stimulation can improve the L* of yak meat during aging. The a* of electrical stimulation treatment was no difference with NC during aging(P>0.05). The b* of electrical stimulation treatment increased fast than NC. But at the end of aging, there is no significant with them(P>0.05);The driping loss of yak meat increases gradually, but the driping loss of electrical stimulation treatment increased slowly. At the end of aging, the driping loss of electrical stimulation treatment was lower than NC significantly(P<0.01). The driping loss of ES&C 72 s is lower than ES&C 90 and 108 s significantly(P<0.05). So the electrical stimulation can delay the increased of driping loss.The electrical stimulation could improve the tenderness of yak. The shear force of electrical stimulation treatment was lower than NC significantly(P<0.01). At the end of chilling, the shear force of ES&C 90 s and 108 s was lower than ES&C 72 s significantly(P<0.01). The MFI of electrical stimulation treatment was higher than NC significantly(P<0.01) during aging. The MFI of ES&C 90 s was highest. At the same time, the TPA was improved, including hardness, gumminess and chewiness.The electrical stimulation damaged the structure of myofiber. Increase the degration rate of myofiber. The myofiber of ES&C 90 s was degraded greatly, and the contracture band appeared too.The electrical stimulation increase the degration rate of Desmin and Troponin-T. Improving the tenderness, and shorten the chilling time.To sum up, the electrical stimulation could prevent cold shorten after slaughter, increased the rate of glycolysis, damaged the structure of myofiber, and increase the degration rate of Desmin and Troponin-T. Maintime it could improve the L*, delay the increased of driping loss, improving the tenderness of yak meat, and shorten the chilling time.