小叶种红茶发酵外观色差及其主要品质成分相关性

Appearance chromatic aberration of fermented leaves of small leaf black tea and correlation analysis of the main quality components

目的依据形成红茶优良品质的理化变化原理,借助现代科学仪器无损检测手段判断小叶种红茶发酵程度。方法在小叶种红茶发酵过程中,对发酵叶色差及不同发酵程度茶样的儿茶素、茶黄素等成分进行跟踪检测。结果发酵叶色差"L,a,b"值逐步上升或下降,其值在180~240 min均有"稳态"的存在,结合不同发酵程度茶样感官审评结果,得出"稳态"即是小叶种红茶发酵的最佳品质状态,尤以210 min最佳。儿茶素含量呈现逐渐下降趋势,茶黄素含量呈现的先增长再下降的变化趋势,茶红素与茶黄素比值的变化情况,均与发酵叶色外观差值存在显著性相关。结论采用统计方法分析色差值与审评结果之间的相关性,探讨小叶种红茶发酵适度的判别指标,提出适度发酵相关判别式ΔL≤0.10,Δa≤0.16,Δb≤0.16和品质的线性回归方程。

ABSTRACT:Objective According to the mechanism of biochemical change results to the quality of black tea, nondestructive scientific instrument was adopted to estimate fermentation degree of small leaf black tea. Methods In the fermentation process of small leaf black tea, the chromatic aberration of fermented leaves and the content of catechins and theaflavins (TFs) were tracked. Results It showed that the values of “L, a, b”were increased or decreased gradually, and that of values were a “steady state” in 180~240 min. At the same time, combined with sensory evaluation results of different degrees of fermentative leaves, the“steady state”was discovered to be the best condition of the fermentation, especially in 210 min. In fermentation process, the appearance chromatic aberration had a significant correlation with the content decreasing gradually of catechins and the primary increasing then deceasing trend of theaflavins(TFs) content, as well as the change of ratio of thearubigins(TRs) and theaflavins(TFs). Conclusion Using statistical method to analyze the dependency of chromatic aberration value and sensory evaluation results, the evaluation index of appropriate fermentation was discussed, the discriminance was suggested that△L≤0.10,△a≤0.16, and△b≤0.16, and the regression equation of the quality was given.