Effects of Deep-fat Frying Temperature and Time on the Quality of Pork Nuggets

The effects of deep-fat frying temperature and time on pork nuggets' quality were evaluated in this research. Changes of pork nuggets' quality after fried at 150,165 and 180℃,respectively,for different times were analyzed by the indexes including color,hardness,moisture content,fat content,protein carbonyls content,thiobarbituric reactive substances(TBARS)value and volatile aldehydes. The results showed that after frying,the brightness of pork nuggests decresed and the redness and yellowness increased,the decreasing of moisture content fried at 150,165 and 180℃ for 470,330 and 230 s were 56.25%,52.82%,48.92%(p<0.05),the moisture loss was less at high temperature in short time. Changes of fat content was not significantly when the frying temperature was 150 and 165℃,but it increased significantly when the pork nuggets were fried at 180℃(p<0.05). Long cooking time increased protein carbonyls,it was 2.17 nmol/mg protein of pork nuggets fried at 180℃ for 150 s. TBARS values and hexanal increased significantly after frying. TBARS values of pork nuggets fried at 180℃ for 150 s were 0.71 mg MDA/kg. A highly significant correlation coefficients of fried pork nuggets treated with 150℃(r=0.962)and 180℃(r=0.997)were observed between TBARS values and hexanal content. Frying at 180℃ for 150s was the best condition for pork nuggets with golden color,good texture and low protein and lipid oxidation.