微波杀青工艺对秋季绿茶的保绿降苦作用

目的：探究微波杀青工艺对秋季绿茶的保绿降苦作用；方法：以茶树品种碧香早秋季一芽二叶茶鲜叶为原料，在传统绿茶杀青、揉捻、干燥加工工艺的基础上，将微波杀青工艺替代传统滚筒杀青工艺，按不同微波强度、微波时间设置了14组微波杀青处理，从感官品质、滋味品质、干茶与汤色色泽三个方面探究微波杀青工艺对秋季绿茶的保绿降苦作用；结果：与传统滚筒杀青工艺相比，采用微波强度500w、杀青时间为3min的微波杀青工艺，所制绿茶色绿味醇且综合感官品质最佳，其水浸出物、茶多酚、氨基酸、咖啡碱、总儿茶素、简单儿茶素的含量显著升高（P<0.05），苦味评价指标酚/氨比、酯型儿茶素含量与总儿茶素含量的比值则显著降低（P<0.05），且干茶与茶汤色泽在绿、明度上均有不同程度的改善；结论：利用微波杀青工艺加工秋季绿茶具有较好的保绿降苦效果，可应用于提高秋季绿茶品质的生产实践。

Effects of microwave fixation process on preserving green color and reducing bitterness in autumn green tea

Objective To investigate the effects of microwave fixation process on preserving green color and reducing bitterness in autumn green tea. Methods Flushes of two leaves and a bud of tea variety Bixiangzao picked in autumn were as raw materials, based on the traditional green tea fixing, rolling and drying processes, the microwave fixation process was used to replace the traditional cylinder fixation process, 14 groups of microwave fixation treatments were set up according to different microwave intensities and microwave times to investigate the effect of microwave fixation process on preserving green color and reducing bitterness in autumn green tea in terms of sensory quality, taste quality components and color quality of dry tea and tea infusion. Results Compared with the traditional cylinder fixation process, the green tea produced by the microwave fixation process with microwave intensity of 500 W and microwave time of 3 min had the best overall sensory quality with green color and mellow taste, while the content of water extract, tea polyphenols, amino acids, caffeine, total catechins and simple catechins were significantly increased (P<0.05), the ratio of tea polyphenols to amino acids for bitterness evaluation indicators and ester catechin content to total catechin content were significantly decreased (P<0.05), and the greenness and brightness of the dry tea color and the tea infusion color were improved in different degrees. Conclusion Microwave fixation processing of autumn green tea has a good effect of protecting green and reducing bitter, which can be applied to improve the quality of autumn green tea production practice.