丝瓜多酚氧化酶及过氧化物酶酶学特性的研究

应用分光光度法研究丝瓜多酚氧化酶及过氧化物酶酶学特性的影响因素,为丝瓜酶促褐变的研究提供基础。以普通丝瓜果肉为材料,PPO以邻苯二酚为底物,POD以愈创木酚为底物,研究分析反应温度、反应时间、pH及测量波长、底物的浓度、PPO提取酶液添加量对丝瓜PPO、POD活性的影响。丝瓜褐变相关酶提取和测定方法的优化:(1)PPO最佳反应体系:测定波长408nm、反应温度是35℃、pH为6.0、酶液用量0.15mL,最适底物为邻苯二酚,底物浓度为0.056mol·L~(-1);(2)POD最佳反应体系:测定波长410nm,反应温度为40℃,最佳pH为5.5,酶液用量0.1mL,底物是愈创木酚,浓度为0.067mol·L~(-1)。

Polyphenol Oxidase and Peroxidase in Luffa cylindrica

Factors affecting the properties of polyphenol oxidase (PPO) and peroxidase (POD) in luffa (Luffa cylindrica) were studied for information relating to enzymatic browning of the vegetable.The temperature,time duration,pH,and concentrations of the substrates,i.e.,catechol for PPO activity and guaiacol for POD activity determinations,applied for the reaction as well as the wavelength used for the spectrophotometric color measurements were analyzed.The results indicated that (1) the optimum reaction system for PPO activity determination required the applications of wavelength at 408 nm for the spectrophotometry,a temperature at 35,a pH of 6.0,and an enzyme dosage of 0.15 mL with 0.056 moL · L-1 catechol;and,(2) the optimum reaction system for POD,wavelength at 410 nm,a temperature at 40,a pH of 5.5,an enzyme dosage of 0.1 mL with 0.067 moL · L-1 guaiacol.