加工工艺对名优绿茶叶素变化的影响

Effect of Processing technology on chlorophylls in famous green tea

用薄层扫描分析法测定了名优绿茶叶绿素组成的变化。结果表明，在针形茶加工过程中，chla、chlb呈下降趋势，pya、pyb呈上升趋势，cda、cdb变化较小。杀青工序和揉捻后做形前期是叶绿素破坏和脱镁叶绿素形成的主要阶段。主要类型名优绿茶叶绿素测定结果表明，chla、pya差异较大，其次是chlb，而cdb、cda、pyb的差异较小。揉捻对名优茶色泽品质有影响．揉捻型名茶叶绿素的含量低于未揉捻型名茶，而脱镁叶绿素的含量则相反。春茶后期以及夏秋季鲜叶加工过程叶绿素的过多破坏和脱镁叶绿素的大量形成是造成叶色发暗的主要原因。

Variations of chlorophylls and their decomposed products in famous green tea (FCT) were analysed by TLC. The results showed that the content of chlorophyll a and chlorophyll b decreased, and that of pheophytin a and pheophytin b increased during processing of needle -- shaped green tea while chlorophyllide a and chlorophyllide b changing slightly. The main stages in which chlorophylls decomPOsed and pheophytins formed greatly were enzyme inactivation and in the earlier period of shaping after rolling. There was more difference in content of chlorophyll a and pheophytin a than chlorophyll b in main kinds of FGT except chlorophyllide a, chlorophyllide b and pheophytin b. There were effects of rolling on color quality of FGT. The contents of chlorophyll in FGT without being rolled were more than in FCT being rolled, but those of pheophytin in the former were less. The main reason causing color dark ening is due to decomposition of chlorophylls and formation of pheophytins greatly during the processing of needle -- shaped green tea made from later spring, summer and autumn fresh leaves. It was also discussed how to improce the color quality of excellent green tea.