Effect of Temperature Fluctuation on the Quality of Chilled Pork

In this paper,the pork longissimus dorsi after 24 h slaughter as raw material,through the analysis of the pH,color,storage loss rate,cooking loss rate,shearing force and low-field nuclear magnetic resonance with different storage times(0,24,48 and 72 h)and temperature(4 ℃,0 and 4 ℃ each for 2 h,4 and 8 ℃ each for 2 h). The results showed that:The pH,b^* values,storage loss rate and cooking loss rate of the pork longissimus dorsi increased significantly(p<0.05)with the increasing of storage time,but the shear force decreased significantly(p<0.05). The pH,b^* values,storage loss and cooking loss also increased significantly(p<0.05)with the increasing of temperature fluctuation,then the shear force decreased significantly(p<0.05).The result of low field nuclear magnetic resonance technology found that:The T_2b,T₂₁ and T₂₂ relaxation times were longer significantly(p<0.05)with increasing storage time,the peak ratios of P₂₁ were lowered,and the peak ratios of P₂₁ were increased. The T_2b,T₂₁ and T₂₂ relaxation times were shorter significantly(p<0.05)with the decreasing of storage temperature and temperature fluctuation,the peak ratios of P₂₁ were increased,and the peak ratios of P₂₂ were lowered. To sum up,the quality of the pork longissimus dorsi would be conducive to maintain when the chilled storage at 4,0,4 ℃ for 2 h each.