普洱茶发酵阶段色泽的变化及其与品质的关系

为阐明普洱茶不同发酵阶段色泽变化及其与普洱茶品质的关系，研究了恒温恒湿与恒温非恒湿条件下，接种外源优势菌（酿酒酵母）与未接种外源优势菌的云南普洱茶在不同发酵阶段的感官品质、汤色的定量分析及茶色素含量的变化。结果表明：明度指数L及明度指数差ΔL与感官指标汤色的评分呈正相关；色品指数a、b及色差值Δa、Δb与汤色感官评分、滋味评分和品质总评分均呈正相关；不同发酵阶段样的ΔL、Δb的值逐渐减小，而Δa的值逐渐增大，这与其茶红素和茶黄素的值逐渐减小和茶褐素的值不断增大是一致的。普洱茶发酵阶段色泽的量化分析可作为普洱茶品质评价的重要指标，在自动化恒温恒湿条件下发酵普洱茶，有利于实现普洱茶清洁化加工和提高普洱茶品质的稳定性。

Relationship between color change and quality of Pu-erh Tea during fermentation

The relationship between the chromatism and the quality of Pu-erh Tea in different fermentation stages were investigated in this paper. Sensory quality, quantitative analysis of tea infusion and the content change in tea pigments in different fermentation stages under conditions of constant temperature and humidity or constant temperature and non-constant humidity were determined in Saccharomyces cerevisiae inoculated or noninoculated Pu-erh Teas. It was found that the brightness index L and the brightness index difference ?L had a positive proportional relationship with the sensory score of tea infusion color. Chromaticity index (a, b) and chromaticity value (?a, ?b) were significantly positively correlated with sensory value, taste value and total quality value of tea infusion. The values of ?L and ?b gradually decreased during different fermentation stages, but the value of ?a gradually increased. These findings were consistent with the findings that the contents of thearubigins and theaflavins were gradually reduced and theabrownin was increased. These results indicate that the degree of fermentation of Pu-erh Tea can be controlled by chromatic value and that Pu-erh Tea quality can be improved by a system with constant temperature and humidity.