以大西洋马铃薯为原料,分别用柠檬酸-磷酸盐缓冲液浸提和超声波辅助Tris-HCl缓冲液浸提法提取马铃薯中可溶态(sPPO)和膜结合态(mPPO)多酚氧化酶,以酶比活力为评价指标,在单因素实验基础上,通过响应面对sPPO和mPPO的提取工艺进行优化。结果显示:sPPO最优提取工艺为料液比1:3.2、浸提时间12 h、缓冲液pH7.1,在该条件下测定sPPO比活力平均值为(130.5±2.4) U/mg,三个因素对sPPO提取的影响大小依次为:浸提时间>料液比>缓冲液pH。mPPO最优提取工艺为料液比1:5.2、浸提时间7 h、缓冲液pH6.7,在该条件下测定mPPO比活力平均值为(686.4±7.9) U/mg,三个因素对mPPO提取的影响大小依次为:超声时间>料液比>缓冲液pH。所得响应面模型可以很好地预测和分析sPPO和mPPO提取工艺条件。
The soluble(sPPO)and membrane bound(mPPO)polyphenol oxidase were extracted from potato by citric acid combined phosphate buffer solution and ultrasound assisted combined Tris-HCl buffer extraction method,respectively,and the enzyme specific activity was used as the evaluation index. The extraction process of sPPO and mPPO were optimized by response surface method on the basis of single factor experiments. The results showed that the optimal extraction process of sPPO were as fllows:The solid-liquid ratio was 1:3.2,the extraction time was 12 h,and the buffer pH was 7.1,the specific activity of sPPO was(130.5±2.4) U/mg under this condition. The influence of three factors on sPPO extraction were as follows:Extraction time>solid-liquid ratio>buffer pH. The optimal extraction process of mPPO were as fllows:The material-liquid ratio was 1:5.2,the extraction time was 7 h,and the buffer pH was 6.7,the specific activity of mPPO was(686.4±7.9) U/mg under these condition. The influence of three factors on mPPO extraction were as follows:Ultrasonic time>solid-liquid ratio>buffer pH. The extraction conditions of sPPO and mPPO could be predicted and analyzed by the response surface model.