油炸温度和时间对猪肉块品质的影响

本文研究了不同油炸温度和时间对猪肉块品质的影响,分析了150、165和180℃条件下油炸不同时间后猪肉块的色泽、硬度、水分含量、脂肪含量、蛋白质羰基含量、硫代巴比妥酸值(TBARS值)和挥发性醛类物质的变化情况。实验结果表明,油炸后猪肉块的亮度降低,红度和黄度升高;硬度在油炸过程中变化显著(p<0.05),150℃油炸470 s时达到最大值37.59 kg;150、165和180℃分别油炸470、330和230 s后猪肉块的水分含量减少了56.25%、52.82%和48.92%(p<0.05),高温短时油炸条件下水分损失较少;脂肪含量在150、165℃时随时间变化不显著,180℃油炸时随时间的延长显著增加(p<0.05);蛋白质羰基含量随油炸时间的延长而增大,180℃油炸150 s时猪肉块的蛋白质羰基含量为2.17 nmol/mg;TBARS值和己醛含量在油炸后迅速增大,之后呈现先减小后均大的趋势,180℃油炸150 s的TBARS值为0.71 mg MDA/kg;挥发性醛类物质中己醛与TBARS值相关性显著,150、180℃条件下的相关系数分别为0.962和0.997。180℃油炸150 s时的猪肉块具有金黄的色泽,硬度适中,脂肪和蛋白质氧化程度较小,具有较好的品质。

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.