福建农林大学学报（自然科学版）2016，Vol.45Issue(3)：262-268,7.DOI:10.13323/j.cnki.j.fafu(nat.sci.).2016.03.005
不同LED光质萎凋对白茶品质的影响
Effect of different LED lights in withering on quality of white tea
摘要
Abstract
To investigate artificial illumination as withering process for high grade of aroma and taste, red, yellow, green, blue, white light emitting diode ( LED) lights at 5 levels of wavelength and illuminance and no-lighting withering as control were tested on white tea. Leaf temperature, moisture content and polyphenol oxidase ( PPO) were measured every 6 h. Aromatic constituent analy-sis and sensory evaluation were integrated for optimum tea quality. Results showed that it took 48 h to complete the withering process for LED groups while it was 56 h for the control. PPO activity peaked once in white LED group but twice in the other five groups. Peak of PPO activity for the control was 6 h after those of all the illuminated gourps. Tea polyphenols levels were significantly lower in blue group (28.43%) than the other five groups (P<0.01). Amino acids were highest in yellow group (4.35%) and lowest in the control (3.96%). Total caffeine in yellow group and the control were significantly lower than the other four groups (P<0.05). Fla-vonoid content was highest in blue group (9.04 mg��g-1). A total of 44 aromatic components were detected from 6 gourps of tea. A-mong them, 34 kinds were found in red group, 37 kinds in yellow, 31 kinds in blue, 23 kinds in green, 24 kinds in white, 24 kinds in the control. Weights of total aromatic components with the largest group in a descending were blue>white>yellow>red>green > control, with weight of blue group being 1.84 times larger than the control. Among all the groups, hexanal and 1-nonanol were only found in yellow group, and ( E)-2-hexenal, neroli, benzeneethanol in yellow group were higher than those of the other 5 groups. Moreover, sensory evaluation comfirmed that aroma from yelllow group smelled clean with flowery. Sensory evaluation com-firmed that white tea withered by yellow and blue lights were dark green and prettier in shape. They both had clean and fresh aroma, and mellow taste, especially pleasant flowery flavor was detected in aroma and taste of yellow gourp. Secondly, white tea withered by green and white lights had clean and pure aroma, though mellow taste was detected in green group. Nevertheless, mild to grassy smell were found in red group and the control, and flatter and less evenly tea-shape were found in the control. To summarize, LED light quality posed significant impact on the appearance, aroma and taste of white tea. Yellow LED light was likely to be the optimum withering illumination for best tea quality.关键词
发光二极管(LED)/白茶/光照萎凋/品质Key words
light emitting diode ( LED)/white tea/light withering/quality分类
农业科技引用本文复制引用
罗玲娜,林永胜,周子维,郭佳星,李思偲,孙云,郭春芳..不同LED光质萎凋对白茶品质的影响[J].福建农林大学学报（自然科学版）,2016,45(3):262-268,7.基金项目
国家自然科学基金资助项目(31270735)；国家“十二五”科技部支撑计划项目(2014BAD06B06)；福建省现代农业(茶叶)产业技术体系项目(闽财指[2015]0640)；福建茶产业农技推广服务试点建设项目(KNJ-151000) （31270735）
