Study On Effect Of Slaughtered Seasons And Pre-slaughter Drive On The Quality Of Donkey Meat During The Postmortem Aging

Donkey meat is a kind of high-quality meat.It is delicious in taste,rich in essential amino acids and nutrients.Different slaughter conditions will affect the quality of meat,however,due to the few research of donkey meat,there is no slaughtering norm for it,and the scale of donkey farming is too small to leads to regulated pre-slaughter management and slaughtering methods.Pre-slaughter stress is one of the important factors affecting the quality of donkey meat.The paper measures the pH value,drip loss,cooking loss,total volatile basic nitrogen?TVB-N?,texture characteristics,colors,total number of colonies,myofibril fragmentation index?MFI?,myofibrilar protein solubility,glycogen,heat shock protein 70?Hsp70?,SDS-PAGE gel electrophoresis and microstructure of muscle tissue of donkey meat slaughtered in the three seasons of winter,spring,summer,and donkey meat without or after drive before slaughtered to explored the impact of slaughter season and pre-slaughter drive on the quality of donkey meat.This paper can provide theoretical basis and technical support for the quality evaluation of donkey meat and the improvement of slaughtering technology and conditions.It was found that slaughtered in different seasons had a significant effect on the quality of donkey meat.Slaughtered at high temperature in summer resulted in a significant decrease in the pH value of the donkey meat after slaughter.The drip loss and cooking loss were significantly increased,and the meat hardness,elasticity,cohesiveness and chewiness were reduced.The L*value was increased,the a*value was decreased,the total number of colonies was higher,and the MFI value,TVB-N value,myofibrilar protein solubility,glycogen content,and Hsp70 content were significantly increased.The pH value of donkey meat after slaughtered in winter was higher than that in spring and summer.The drip loss and cooking loss were significantly reduced.The hardness,chewiness and cohesion of the meat were increased,the elasticity was significantly reduced,and the a*value was significantly increased.MFI value,TVB-N value and myofibrillar protein dissolution was decreased,while the Hsp70 content was increased.By studying the indexes of SDS-PAGE electrophoresis and myofibrillar microstructure of donkey meats slaughtered in different seasons,the results showed that with the increase of postmortem aging,in summer the degradation of protein was fastest,the protein of spring group degraded the most slowly.The microfibrous structure of myofibrils showed that the myofibril gap gradually increased with the increase of maturity time.In the late stage of postmortem aging,the gap of summer group was significantly higher than that of spring and winter,and the shape was more irregular.The study found that the pre-slaughter drive had a significant impact on the quality of the donkey meat after slaughter.The pH value was lower than that of the control group at 6h after the slaughter group,but the limited pH value was higher than that of the control group,and the pH value was higher than that of the control group.The drip loss and cooking loss were higher than that of the control group.The hardness,cohesiveness and chewiness of the donkey meat after slaughtered were significantly higher than that of the control group.The L*value was increased,the a*value was significantly higher than that of the control group.The MFI,the myofibrilar protein solubility and the TVB-N value were significantly lower than those of the control group,but were higher than the control group at the later stage,The glycogen content of drive group was significantly lower than that of the control group,and had a significant difference at 1^st day.The content of Hsp70 in the drive group at 1^st day and 3^rd day was significantly higher than that of control group.By studying the SDS-PAGE electrophoresis and the myofibrillar microstructure of the meat that was driven by pre-slaughter,the results showed that as the postmortem aging increased,both groups of proteins degraded,but the drive group degradation was faster.The microfibrous structure of myofibrils showed that the myofibril gap gradually increased with the increase of postmortem aging.At the late stage of postmortem aging,the gap of the drive group was higher than the control group,and the shape arrangement was more irregular,indicated that the degree of myofibril degradation was higher.