烫漂过程中荠菜过氧化物酶失活动力学模型研究

Kinetic Models of Peroxidase Inactivation in Capsella bursa-pastoris during Blanching

采用一级动力学模型、Weibull分布模型、Logistic模型对荠菜烫漂过程中过氧化酶失活动力学模型进行拟合。以决定系数(R^(2))、卡方(x^(2))、均方根误差(RMSE)、精确因子(A_(f))、偏差因子(B_(f))等为评价指标,分析模型的拟合效果。利用模型预测不同烫漂温度的烫漂工艺条件,同时以维生素C的含量为指标,评价不同烫漂工艺对维生素C含量的影响。结果表明:Logistic模型拟合烫漂过程中荠菜过氧化物失活动力学效果好,拟合精度高,拟合值与实测值偏差小,其决定系数R^(2)为0.9980,x^(2)为0.96×10^(-4),RMSE为0.0097,A_(f)为1.1304,B_(f)为1.0070。在过氧化物酶95%失活的条件下,依据Logistic模型预测,100℃下烫漂20 s,80℃下烫漂287 s,POD相对酶活在0.050±0.001之间;烫漂后维生素C含量也存在显著性差异,高温短时烫漂后的维生素C损失较少。POD失活动力学模型预测烫漂工艺条件,可以减少维生素C等热敏性营养成分损失。

The inactivation kinetic of peroxidase in Capsella bursa-pastoris during blanching was evaluated using firstorder,Weibull,and Logistic models.The goodness-of-fit of the three tested models was assessed using the coefficient of determination(R^(2)),chi-square(x^(2)),root mean square error(RMSE),accuracy factor(A_(f)),bias factor(B_(f)).Moreover,the best goodness-of-fit model was used to predict the blanching process according to the content of vitamin C.The results indicated that the Logistic model was most suitable than other models for predicting POD inactivation.The performance of the Logistic model indicated a strong fit by the high coefficient of determination(R^(2)=0.9980)and low prediction error(x^(2)=0.96×10^(-4),RMSE=0.0097,A_(f)=1.1304,B_(f)=1.0070).While the blanching inactivated 95%peroxidase activity in Capsella bursa-pastoris,the relative enzyme activity of POD was 0.050±0.001 after blanching at 100℃for 20 s and 80℃for 287 s according to Logistic model.There was a significant difference in vitamin C content after blanching,hightemperature-short-time blanching could reduce the loss of vitamin C.The inactivation kinetic model of POD can predict the blanching process conditions,which can reduce the loss of heat-sensitive nutrients such as vitamin C.