丰金玉等

摘 要：以‘桃源大叶茶1芽2叶为材料，研究多酚氧化酶、过氧化物酶和β-葡萄糖苷酶在工夫红茶加工工艺中的动态变化，分析加工叶水分含量对3种酶酶活性的影响，以期为高香高茶黄素红茶的加工提供参考。结果表明，随着萎凋时间延长，3种酶酶活性均呈现不同程度的增加，萎凋14 h后，多酚氧化酶酶活性达到鲜叶的2.9倍，过氧化物酶酶活性达到鲜叶的3.5倍，β-葡萄糖苷酶活性达到鲜叶的2.1倍，在揉捻、发酵、干燥工艺中，3种酶活性不同程度地下降。根据研究结果可推断，β-葡萄糖苷酶对红茶香气品质的影响主要表现在萎凋过程及发酵早期，多酚氧化酶、过氧化物酶对红茶滋味品质的影响主要集中在发酵工艺，可依据萎凋叶中3种酶的活性变化程度及失水情况，确定萎凋适度的标准，依据发酵叶中的多酚氧化酶与过氧化物酶的比值变化情况，确定发酵适度的标准。

关键词：茶叶加工；红茶；多酚氧化酶；过氧化物酶；β-葡萄糖苷酶

中图分类号：S571.1 文献标志码：A 论文编号：2014-0292

Activity Changes of Polyphenol Oxidase， Peroxidase and β-Glycosidase in Black Tea Processing

Feng Jinyu1， Liu Kunyan1， Qin Yu1， Xiong Shuo1， Deng Yanli1， Gong Zhihua1， Xiao Wenjun1，2

（1Hunan Agricultural University， Changsha 410128， Hunan， China；

2Changsha Herun Tea Industry Technology Ltd， Changsha 410128， Hunan， China）

Abstract： By using one bud two leaves of ‘Taiyuan big leaf species in the summer as materials， the dynamic activity changes of polyphenol oxidase， peroxidase and β-glycosidase in processing black tea and the effect of water moisture of processing leaves on the enzyme was studied in order to provide reference for processing high incense and high theaflavins black tea. The results showed that with the extension of withering time， the activity of the three enzymes increased differently， after 14 hours withering， polyphenol oxidase activity increased 2.9 times， peroxidase activity increased 3.5 times， and β-glycosidase activity increased 2.1 times. In rolling， fermentation， drying process， the activity of three kind enzymes decreased differently. According to the results， it could be inferred that β-glycosidase affected aroma quality of black tea mainly in the process of fermentation and early withering， polyphenol oxidase， peroxidase affected the taste quality of black tea mainly in the process of fermentation. According to the degree of activity change the three kind enzyme and the condition of water loss in the withering leaves， the appropriate criteria black tea processing could be determined， and the appropriate criteria of fermentation also could be determined according to the ratio changes of polyphenol oxidase and peroxidase.

Key words： Tea Processing； Black Tea； Polyphenol Oxidase； Peroxidase； β-Glycosidase

0 引言

多酚氧化酶（PPO）、过氧化物酶（POD）和β-葡萄糖苷酶是红茶加工中影响红茶色、香、味品质形成的3种关键酶[1-2]，其中，PPO主要影响茶黄素的酶促合成，POD主要影响茶黄素的酶促过氧化，β-葡萄糖苷酶则主要影响糖苷类香气物质的释放，因而如何科学调控3种酶的活性并加工高香高茶黄素红茶，是红茶加工化学和品质化学的重点。Bokuchava等[3]、竹尾忠一等[4-5]研究表明，PPO、POD在茶鲜叶的萎凋、揉捻工艺中，活性逐渐增加，且揉捻叶酶活性高达茶鲜叶酶活性的2～3倍。……