褐变抑制剂对苹果多酚氧化酶抑制机理研究  

Mechanism of different inhibitors on apple polyphenol oxidase in a model system

作　　者：易建华[1] 董新玲[1] 朱振宝[1] 赵雪萌 

机构地区：[1]陕西科技大学生命科学与工程学院,陕西西安710021

出　　处：《食品与机械》2015年第4期122-125,共4页Food and Machinery

基　　金：国家自然科学基金项目(编号:31101326);咸阳市科技局自然科学项目(编号:2010k12-16);陕西省人力资源与社会保障厅出国留学人员科技活动项目

摘　　要：为研究不同褐变抑制剂对苹果多酚氧化酶(PPO)活性的抑制机理,采用磷酸缓冲液构建苹果汁模拟体系,选取苹果中含量较多的酚类物质绿原酸作为试验对象,以磷酸缓冲液为苹果汁模拟体系,选取4-己基间苯二酚(4-HR)、草酸、苯甲酸和对甲氧基苯甲酸为抑制剂,通过模拟试验研究抑制剂对绿原酸模拟苹果汁酶促褐变特性的影响,揭示抑制剂对苹果汁PPO的作用机理。结果表明,抑制剂对PPO的抑制机理差异较大,其中4-HR和草酸对PPO的抑制作用为竞争性抑制,植酸为混合性抑制,而苯甲酸为非竞争性抑制。该研究可为利用抑制剂控制苹果汁褐变提供理论依据。In order to study the mechanisms of different inhibitors such as 4-HR, oxalic acid, phytic acid, and benzoic acid on apple polyphenol oxidase （PPO）, chlorogenic acid was chosen as substrates in a model apple juice. The results show that the inhibitory mode of 4-HR and oxalic acid were found to be of the competitive type since Km values increased with increasing 4-HR and oxalic acid concentra tion and Vmax value remained unchanged. Phytic acid was the mixed inhibitor whereas benzoic acid was a noncompetitive inhibitor. This study will provide a theoretical basis for controlling enzymatic brown- ing in apple juice.

关 键 词：苹果汁 褐变抑制剂 酶促褐变 PPO 绿原酸 

分 类 号：TS255.1[轻工技术与工程—农产品加工及贮藏工程]