Effects of Different Cooling Methods on Quality of Mutton after Slaughter

In order to establish an appropriate cooling procedure for post-mortem mutton,different cooling methods(Conventional cooling,0~4℃ for 96 h),Delay cooling,(15±0.5)℃ cooling for 8 h,and then cooling to 96 h at(0~4℃),High temperature cooling,(25±0.5)℃ cooling for 2h,and then placed in the condition of 0~4℃ continue cooling to 96 h)were used to cool post-mortem mutton,and the effects of different cooling methods on the quality of mutton were studied.The results showed that delayed cooling and high temperature cooling significantly increased the cooking loss of mutton,reduced the value of mutton shear force,improved the tenderness of mutton,and shortened the ripening time of mutton(P<0.05). Meanwhile,L^* value and a^* value of mutton were improved(P<0.05),making mutton brighter red in color. In addition,high temperature cooling and delayed cooling increased the carbonyl content of mutton(P<0.05),and decreased the content of sulfhydryl group(P<0.05). The higher the temperature,the greater the oxidation degree of mutton protein. Moreover,the total number of colonies under high temperature cooling was significantly higher than that under conventional cooling and delayed cooling(P<0.05),and there was a risk of corruption. The experiments showed that delayed cooling and high temperature cooling had positive effects on the improvement of mutton quality,but considering the factors of microorganism and protein oxidation,delayed cooling is more suitable for post-mortem mutton cooling.