醇香酶解绿茶浓缩液工艺研究

随着制茶工艺学的发展和各门科学技术的相互渗透,酶技术在茶叶加工尤其是深加工中的应用愈来愈多。以绿茶为原料,采用固定化单宁酶、纤维素酶、风味蛋白酶和β-葡萄糖苷酶进行复合酶解浸提制备绿茶浓缩液,利用HPLC、GC-MS和氨基酸自动分析仪对茶浓缩液中的有效成分和香气成分进行测定,并与常规水浸提法制得的茶浓缩液进行比较,结果显示:此工艺条件浸提所得绿茶浓缩液中茶多酚、氨基酸含量都高于常规绿茶浓缩液,其中儿茶素组成发生了很大变化,酯型儿茶素EGCG、ECG的含量比常规绿茶浓缩液低,而非酯型儿茶素EGC、EC以及没食子酸(GA)的含量则明显提高,且浓缩液开汤后味道浓醇、鲜爽;用SDE法提取香气成分,酶解茶浓缩液的香气物质含量显著高于常规绿茶浓缩液,并且比常规绿茶浓缩液多了1-戊烯-3-醇、4-萜烯醇、1-辛烯-3-醇等多种特有香气成分。

Research on enzymolysis of a mellow green tea concentrate

With the development of tea technology and interpenetration of various sciences and technologies, the enzymatic technology has been more and more applied to the processing, pa~cularly in-depth processing of tea. A concentrate was extracted from green tea by composite enzymolysis-extraction with immobilized tannase, cellulase, flavorzyme and ~3-glucosidase. Then, the active and aromatic components in the concentrate were determined by HPLC, GC-MS and with an automatic amino-acid analyzer, and a comparison was conducted with a tea concentrate obtained by the conventional water extraction. The results showed that the enzymatic method was superior to the conventional water extraction in more tea polyphenols and amino acids in the concentrate, as well as a great change in the composition of catechins. Estered catechins EGCG and ECG were fewer than those in the concentrate obtained by the conventional water extraction, but non-estered catechins EGC, EC and gallic acid （GA） were markedly more; and the concentrate obtained by the enzymatic method tasted more mellow and fresher after diluted. The results of extraction by the SDE method indicated that the aromatic substances in the concentrate obtained by the enzymatic method were greatly more than those in the concentrate obtained by the conventional water extraction, and that some new aromatic substances appeared including 1-penten-3-ol, terpinen-4-ol and 1-octen-3-ol.