腌干鲢鱼组织蛋白酶B、L活力变化的响应面法预测研究

Prediction of Cathepsin B and L Activities in Cured Silver Carp during Drying Using Response Surface Methodology

以鲢鱼为原料,进行腌制和热泵干燥加工,研究内源组织蛋白酶B、L活性在加工过程中的变化。选取加工过程对鲢鱼(Hypophthalmichthys molitrix)组织蛋白酶B、L活力影响较大的3个工艺参数(温度、pH值、盐质量分数)作为试验因素,并根据酶学特性和干燥过程中各理化指标的测定结果确定其试验水平。采用响应面法考察此3因素对组织蛋白酶B、L活性的影响,并根据回归方程对腊干鲢鱼加工过程中的组织蛋白酶活力进行预测。结果表明:回归方程可用于组织蛋白酶B、L实际活力预测;两种酶的潜在活力在加工过程中均呈下降趋势,加工结束时组织蛋白酶B和L的潜在酶活力分别为初始的43.18%和26.08%;通过回归方程对组织蛋白酶B、L在腌制前、腌制后、干燥2d、干燥5d、干燥7d实际活力进行预测,组织蛋白酶B实际酶活力分别为潜在酶活力的36.7%、39.9%、46.5%、46.5%和53.5%,而组织蛋白酶L则为6.6%、5.6%、10.4%、10%和12.6%。

The activities of cathepsin B and L in cured silver carp （Hypophthalmichthys molitrix） were determined during curing and heat pump drying. Three process parameters （temperature, pH and salt concentration） were identified as main variables that influence the activities of cathepsin B and L. According to the properties of both enzymes and the results of physiochemical analysis of cured silver carp during drying, different levels of the main variables were selected to study their effects on the activities of cathepsin B and L by response surface methodology. A separate predicative regression model for the activities of both cathepsin enzymes was proposed and applied. The results indicated that the proposed regression models could be used to predict the activities of cathepsin B and L. The activities of both enzymes in cured silver carp showed a downward trend during processing and 43.18% and 26.08% of their original activities were retained at the end of the drying stage, respectively. The actual activity of cathepsin B before curing, after curing, and after drying for 2, 5 d and 7 d was 36.7%, 39.9%, 46,5%, 46.5% and 53.5% of its potential activity, respectively; the actual activity of cathepsin L at these time points was 6.6%, 5.6%, 10.4%, 10% and 12.6% of its potential activity, respectively as demonstrated by model laredictions.