【作者】 冯云；

【导师】 苏祝成；

【作者基本信息】 浙江大学 ， 茶学， 2007， 硕士

【摘要】 本文研究在夏季绿茶的初制过程中分别添加木瓜蛋白酶、单宁酶、纤维素酶，然后通过理化成分测定，分析茶叶中内含物质的变化，探讨加工过程中添加外源酶对夏季绿茶品质的影响，以期发现合适的酶来达到改进夏季绿茶品质的目的。研究结果表明：1．加工过程中添加木瓜蛋白酶后，茶叶中的茶多酚总量没有显著变化，而氨基酸总量有所升高。在所有木瓜蛋白酶处理的茶样中，不论揉捻时间、酶浓度和原料嫩度差异，处理样中的氨基酸总量都是要高出对照样。例如，在揉捻15min鲜叶嫩度为一芽二叶时，所有木瓜蛋白酶处理的茶样其氨基酸总量平均值为2.40％，比对照(2.20％)高9.09％。2．加工过程中添加单宁酶后，茶叶中的茶多酚总量没有显著变化，而氨基酸总量略有升高。此外，茶样中的儿茶素组分发生了很大的变化。具体表现为：酯型儿茶素总量的下降和非酯型儿茶素的升高。例如，在揉捻15min，鲜叶嫩度为一芽二叶时，单宁酶处理的茶样中，其酯型儿茶素总量平均值为13.80％，比对照(15.94％)低15.54％；非酯型儿茶素总量为9.82％，比对照(9.40％)高4.57％；儿茶素总量为23.62％，比对照(25.34％)低7.26％。3．加工过程中添加纤维素酶后，茶叶中的茶多酚总量没有显著变化，而氨基酸总量有所升高，可溶性糖含量也有所升高。所有纤维素酶的处理样中，虽然揉捻时间、酶浓度、原料嫩度等条件不尽相同，但处理样中的氨基酸总量和可溶性糖含量都是要高出相应的对照。例如，在揉捻15min鲜叶嫩度为一芽二叶时，所有纤维素酶处理的茶样其氨基酸总量平均值为2.46％，比对照(2.20％)高11.82％；可溶性糖含量平均值为3.16％，比对照(2.87％)高10.20％。纤维素酶的主要作用是促进多糖的水解，但试验结果表明，纤维素酶能明显提高茶样中氨基酸总量，对此，可能的原因是：纤维素酶能破坏细胞组织结构，从而使得细胞内部氨基酸的浸出更加容易。4．木瓜蛋白酶的使用，目的是为了提高茶叶中氨基酸的含量，增加夏季绿茶茶汤的鲜爽度；单宁酶的使用，目的是为了降解茶叶中的酯型儿茶素，减轻茶汤的苦涩味；纤维素酶的使用，目的是为了提高可溶性糖含量，增加茶汤的甜醇度，实验结果表明：三种外源酶的使用都达到了预期的目的；实验同时发现，纤维素酶也可以提高氨基酸含量，而且效果要好于木瓜蛋白酶。更多还原

【Abstract】 In the present paper, physical and chemical analysis methods were employed to study the changes of biochemical inclusions in green tea plucked and processed in summer, after being treated with papain, tannase and cellulose enzyme. Based on the effects of exotic enzyme on green tea plucked and processed in summer in this study, the paper aims to develop the green tea processing technology and to find the proper enzyme to improve the quality of green tea.1. After being treated with papain in processing phase, it was found that the content of tea polyphenols in green tea was changed a little, but total amino acid was increased differently. The content of amino acid in all treated samples was much more than the control, although the twisted time, the concentration of enzyme and tender of material was quite different. For example, when the material of 1 bud 2 leaves twisted for 15min, the amino acid content of the samples which were treated with papain was 2.40%, 9.09% higher than the control in average.2. In the samples treated with tannase in processing phase, the content of tea polyphenols and amino acid changed a little, but components of catechin changed a lot. The content of EGCG and ECG decreased, whereas the content of EGC and EC increased. For example, when the material of 1 bud 2 leaves twisted for 15min, EGCG and ECG content of the samples which were treated with tannase was 13.80%, 15.54% lower than the control. The content of EGC and EC was 9.82%, 4.57% higher than the control. And total catechin was 23.62%, 7.26% lower than the control.3. After being treated with cellulose enzyme in processing phase, it was found that the content of tea polyphenols in green tea was changed a little, and the content of amino acid and the content of soluble sugar were increased significantly. The content of amino acid and the content of soluble sugar, with the different levels of twisted time, concentration of enzyme and tender of material were much more than the control. For example, when the material of 1 bud 2 leaves twisted for 15min, the amino acid average content of the samples which were treated with cellulose enzyme was 2.46%, 11.82% higher than the control(2.20%); the average content of soluble sugar was 3.16%, 10.20% higher than the control. The purpose of using cellulose enzyme was to promote the hydrolyzation of amylose, whereas, the result showed that the total amino acid was improved obviously by the usage of cellulose enzyme. It was the possible explanation that the form of cell was destroyed by cellulose enzyme so that the appearance of amino acid was easy.4. The purpose of using papain was to improve the content of amino acid and to increase the smooth feeling of tea; the purpose of using tannase was to decompound the content of EGCG and ECG and to decrease the acerbities of tea. These arguments were testified by the result of the research. Meanwhile, the usage of cellulose enzyme also could improve the content of amino acid, and the effect was better than the effect of papain.更多还原