真空浸渍辅助L-半胱氨酸对鲜切马铃薯多酚氧化酶活性的抑制作用

Inhibition of PPO activity in fresh-cut potato by L-cysteine and vacuum impregnation

为研究真空浸渍辅助L-半胱氨酸(L-cysteine,L-cys)处理对鲜切马铃薯多酚氧化酶(Polyphenoloxidase,PPO)活性的抑制作用,首先通过单因素试验,考察真空时间(t1)、浸渍时间(t2)、L-cys浓度对PPO活性的影响效果,然后采用响应面Box-Behnken中心组合法分析了各个响应因素之间的交互作用对PPO活性的影响,并建立了回归方程预测模型。结果表明,各单因素对PPO活性均有显著的抑制作用,最佳条件分别是:t1为12min、t2为4min和L-cys浓度为1.2g/kg。响应面分析法得到的优化条件参数是t1为740s,t2为250s及L-cys浓度为1.06g/Kg时对PPO活性的抑制效果最佳。在此条件下所得PPO活性为99.75U,与理论值97.2539U的相对误差在2.5%左右。证明此模型具有较好的拟合度,可以预测抑制鲜切马铃薯PPO活性的最佳真空浸渍条件。

In order to inhibit polyphenol oxidase(PPO)activity in fresh-cut potato,the effect of vacuum impregnation with L-cysteine(L-cys)treatment was investigated. By single factor experiment,the vacuum time(t1),restoration time(t2)and L-cys concentration on inhibition of PPO activity was evaluated. The t1,t2 and L-cys concentration were selected as independent variables,and PPO activity was response value. The effects of each independent variable and their interactions on PPO activity of fresh-cut potato was studied by Box-Behnken design. The prediction model of regression equation was established. Single factor experiment showed every factor had the effect on PPO activity,and the optimal conditions of inhibition of PPO activity were: 12 min of t1,4 min of t2,and 1.2 g/kg of L-cys. The response surface experiment showed the optimal conditions for inhibition of PPO activity were: t1 740 s,t2 250 S,and L-cys 1.06 g/Kg. Under the above conditions,the PPO activity was 99.75 U,very close to the predict value 97.2539 U,with relative error about 2.5%. This shows that the model fit well with the reality,and can be used in predicting the optimal vacuum impregnation conditions on inhibition of PPO activity in fresh-cut potato.