乌龙茶加工过程中色差变化研究

Changes of color difference during the Oolong tea processing

利用美能达CT310色差计测定了金萱、翠玉、黄棪、白叶单枞茶4个品种闽南工艺传统乌龙茶加工过程中的色差变化。结果表明,原料经晒青、晾青后,L值(明亮度)和b值(黄蓝色度)增加,a值(红绿色度)减少(即绿度增加),其可能与茶青经摊放后"回水返阳"有关;做青使L值和b值降低,a值增加,白叶单枞茶表现尤为明显,这与其多酚类物质含量和多酚氧化酶活性高有关;随着工序进程的不断深入,L值、b值继续下降,a值不断增加,4个品种趋势相同,仅在量上稍有差异。

Changes of color difference during the Oolong tea processing of 4 cultivates-Jinxuan, Cuiyu, Huangdan and Baiye Dancong, were measured by Minoha CT310 color difference meter. The results showed that the values of L （bright degree） and b （yellow degree） increased and the value of a reduced （green degree increased） after sunshine wither and leaf cooling. The values of L and b reduced and a increased after making green. This phenomenon was notable on Baiye Dancong. Following the processing, the values of L and b reduced and a increased continuously. The tendencies were similar among 4 cuhivars, there were only some slightly difference in quatity.