目的：研究面粉中多酚氧化酶（PPO）活性测定方法。方法：在不同的料液比、反应温度、底物浓度、反应时间等测定条件下，控制pH在6．0、反应测定波长为410nm，以邻苯二酚为底物、使用磷酸盐缓冲液、用分光光度法测定面粉中PP0活性，分析测定条件对面粉中PPO活性的影响。结果：反应料液比、底物浓度、反应时间、反应温度对面粉中PPO活性的测定有着重要影响。料液比较低时测定结果较高，误差较大；料液比大于1．0／10时测定结果较稳定。底物浓度0．12mol／L时限制反应进行，在0．13～0．2mol／L测定结果没有显著差异。反应时间大于15min会影响测定结果。PPO活性测定最佳温度为35℃。%To research the method of measuring polyphenol oxidase （PPO） activity in wheat flour, using catechol as sub strate, polyphenol oxidase activity of wheat flour was determined by spectrophotometry at 410nm under different conditions of Solid-liquid ratio, substrate concentration, reaction temperature and time, and at the same time control pH at 6.0. The results showed that the optimum Solid-liquid ratio, substrate concentration, the raction temperature and reaction time were very important to the measurement of PPO activity.When the solid-liquid was low, PPO activity was higher than other sol- id-liquid lever, the measuring error was higher too.As the solid-liquid was above 1.0/10g/mL, the results of determination were stable. Reaction was confined by substrate concentration of 0.12mol/L, and determination results of 0.13 -0.20mol/L substrate concentration did not have significance difference. Reaction time should be controlled under 15min. The optimal reaction temperature of PPO in wheat flour was 35℃.
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