鲜切甘薯不同部位褐变机理差异  

Mechanism of Browning in Different Parts of Fresh-Cut Sweet Potato

作　　者：王礼群 刘硕[1] 杨春贤[2] 张欣怡[1] 姚世响[1] 邓丽莉[1] 曾凯芳[1] WANG Liqun;LIU Shuo;YANG Chunxian;ZHANG Xinyi;YAO Shixiang;DENG Lili;ZENG Kaifang(College of Food Science, Southwest University, Chongqing 400715, China;Sweet Potato Engineering Technology Research Center, College of Life Sciences, Southwest University, Chongqing 400715, China)

机构地区：[1]西南大学食品科学学院,重庆400715 [2]西南大学生命科学学院,重庆市甘薯工程技术研究中心,重庆400715

出　　处：《食品科学》2018年第1期285-290,共6页Food Science

基　　金：重庆市社会事业与民生保障科技创新主题专项(Cstc2015shms-ztzx80010);西南大学本科生科技创新项目(SPXY201605)

摘　　要：以‘渝薯17’甘薯为实验材料,将鲜切甘薯分为皮部、周边以及中心3个部位。通过对冷藏过程中鲜切甘薯不同部位褐变情况、褐变底物酚类物质含量、褐变相关酶活力的比较研究,探讨鲜切‘渝薯17’不同部位的褐变机理及差异。结果表明,绿原酸是甘薯褐变的主要底物,鲜切甘薯不同部位褐变存在差异,皮部褐变最严重,周边次之,中心最弱。皮部总酚和游离酚含量均显著高于周边和中心组织(P<0.05),其中主要底物绿原酸含量为周边和中心组织的3~4倍。多酚氧化酶(polyphenoloxidase,PPO)是引起皮部组织褐变的主要酶,苯丙氨酸解氨酶对酚类物质的积累起促进作用;周边组织褐变由PPO和过氧化物酶(peroxidase,POD)协同作用催化;中心组织褐变则主要由POD引起。In this paper, fresh-cut sweet potato ‘Yushu No. 17’ was divided into three parts including skin, peripheral and central part. The mechanism of browning in different parts of fresh-cut sweet potato was studied by measuring the browning index, the content of phenolic compounds and the activity of browning-related enzymes. The results showed that chlorogenic acid was the major browning substrate in sweet potato. There were differences in browning among different parts of fresh-cut sweet potato, with the most severe browning occurring in the skin, followed by the peripheral and central parts. The contents of total and free phenols in the skin were significantly higher than those in the peripheral and central tissues （P 〈 0.05）, with a 3 to 4-fold increase being observed in the content of chlorogenic acid. Polyphenol oxidase （PPO） was the major enzyme responsible for the browning process of skin tissue. L-phenylalanine ammonia-lyase promoted the accumulation of phenolic substances. The browning process of peripheral tissue was catalyzed by PPO and peroxidase （POD）, while that of central tissue was mainly caused by POD. The moisture content of sweet potato tissue decreased with storage time.

关 键 词：鲜切甘薯 酶促褐变 绿原酸 多酚氧化酶 过氧化物酶 

分 类 号：TS255.3[轻工技术与工程—农产品加工及贮藏工程]