酥梨多酚氧化酶的提取及其性质  

Characterization of Polyphenol Oxidase in Crisp Pear

作　　者：常大伟[1] 魏送送[1] 

机构地区：[1]陕西科技大学生命科学与工程学院,西安710021

出　　处：《食品工业》2014年第2期88-91,共4页The Food Industry

基　　金：陕西科技大学博士科研启动基金(BJ11-13);陕西省科技厅项目(2012JQ3013)

摘　　要：酥梨中的多酚氧化酶(PPO)是梨汁褐变的主要原因,对酥梨对PPO的活性进行研究。用酚结合剂从酥梨中提取PPO,采用分光光度法,研究了温度、pH、底物浓度、酶液添加量等对酥梨中PPO活性的影响。结果表明,酥梨PPO的最适温度是35℃,在100℃,7 min的条件下能够完全钝化酶的活性;最适pH是5.5;以邻苯二酚为底物时,所得K m=0.025 mol/L,Vmax=187.970 U/min。4种抑制剂的抑制效果为:抗坏血酸>EDTA-Na2>β-环糊精>柠檬酸,而β-环糊精是一种较好的褐变抑制辅助剂。Polyphenol oxidase （PPO） is the main reason for browning of pear juice. The characteristics of the PPO extracted from crisp pear by PVPP. Spectrophotometric method was applied in this experiment to analyzed the effects of temperature, pH, substmte concentration and enzyme concentration on the activity of polyphenol oxidase （PPO）. The results showed that the optimum temperature was 35 °C and the enzyme was completely inactivated at 100 °C for 7 min; the optimum pH was 5.5; Km and Vmax were 0.025 mol/L and 187.970 U/min for catechol. The order of four inhibitors＇ inhibition effects from strong to week was as follows： ascorbic acid, EDTA-Na2, β-cyclodextrins, citric acid, and β-cyclodextrin behaved as mixed-type inhibitors.

关 键 词：酥梨 多酚氧化酶 酶活 褐变 

分 类 号：TS201.25[轻工技术与工程—食品科学]