郑楚珊 詹嘉红

摘 要：过氧化物酶（POD）是参与酚类物质氧化，并且在果蔬酶促褐变中发挥着重要作用的主要酶类之一。该研究以台湾青枣果实为材料，以愈创木酚为底物，采用分光光度法对该果实POD部分酶学特性进行研究。结果表明，台湾青枣果实POD的最适pH值为5.8，最适温度为40℃。pH值小于3.0时酶基本失活，温度高于70℃时也基本失活。该酶热稳定性较差，100℃处理超过15s时，酶几乎钝化。抗坏血酸和NaHSO对POD有明显的抑制作用，而EDTA的抑制作用较弱。3种化合物的抑制效果依次是抗坏血酸>NaHSO3>EDTA。

关键词：台湾青枣；过氧化物酶；酶学特性

中图分类号 Q554 文献标识码 A 文章编号 1007-7731（2018）14-0025-04

Partial Characteristic of Peroxidase in Indian Jujube Fruits

Zheng Chushan1 et al.

（1Shantou No. 4 Middle School，Shantou 515041 China）

Abstract：Peroxidase（POD） is one of the major oxidases involving in the oxidation of phenolics and plays important roles in enzymatic browning of fruits and vegetables. With spectrophotometry method and based on substrate of guaiacol，the enzymatic characteristics of peroxidase（POD） from Indian jujube fruits were studied. Results showed that the optimum pH and temperature of POD were 5.8 and 40℃. At the pH value of less than 3.0 and the temperature higher than 70℃ were basically undetectable activity. The POD had poor thermal stability，its activity was completely passivated when it was incubated at 100℃ and dealing with more than 15s. Ascorbic acid and NaHSO3 had great inhabitation effect on POD，and EDTA was weaker. Their inhibitory capacity was decreased in the order：ascorbic acid>NaHSO3 >EDTA.

Key words：Indian jujube（Ziziphus mauritiana Lamk.）；Peroxidase；Enzymatic characteristic

臺湾青枣（Ziziphus mauritiana Lamk.），又称毛叶枣、印度枣、滇刺枣、西西果等，属鼠李科枣属植物[1]。台湾青枣是我国从台湾引进的热带亚热带特色水果，果实营养丰富，富含维生素、矿物质、膳食纤维及大量黄酮类化合物，尤其是VC含量，每100g台湾青枣果肉VC是苹果的56倍[2]，比号称“VC之王”的中华猕猴桃（47～255mg/100g）含量还高[3，4]，因而，有“热带小苹果”、“天然维生素丸”的美称。台湾青枣以其果大，核细，甜度适中，口味独特，并具有较高的药用价值和保健作用，如健脾强身、清凉解毒、镇静安神等功效[5]，越来越受到消费者的喜爱。但台湾青枣果实较不耐贮藏，鲜果在常温下极易失水皱缩、变黄、变褐和腐烂，严重影响其商品价值和食用品质[6]，其中，酶促褐变是台湾青枣品质下降的一个重要原因。

过氧化物酶（peroxidase，简称POD）是果蔬中普遍存在的一类氧化还原酶，是果蔬成熟和衰老的生理指标[7]，研究表明过氧化物酶参与了果蔬的酶促褐变[8-10]。近年……