浅盘与传统普洱茶发酵的微生物群落和化学成分比较研究

传统普洱茶渥堆发酵一般包含数吨茶叶基质,发酵中存在热传递不均匀的问题.为此建立了浅盘普洱茶发酵系统,并比较了浅盘与传统普洱茶发酵的微生物群落结构和化学成分差异.测定发现2种发酵过程化学成分变化规律类似,浅盘发酵出堆样的水浸出物、可溶性糖、茶红素和黄酮质量分数显著高于传统发酵出堆样(p0.05),茶褐素质量分数显著低于传统发酵出堆样(p0.05). 2种发酵过程微生物群落结构不同,传统发酵出堆样品优势细菌为葡萄球菌属(Staphylococcus)、芽孢杆菌属(Bacillus)和考克菌(Kocuria),优势真菌为曲霉属(Aspergillus)、芽生葡萄孢酵母属(Blastobotrys)和根毛霉(Rhizomucor);浅盘发酵出堆样品优势细菌为芽孢杆菌属(Bacillus)和欧文氏菌属(Erwinia),优势真菌为Brunneoclavispora和曲霉属(Aspergillus).审评结果表明, 2种发酵出堆茶样都具有较好的感官品质.今后还应研究优化浅盘发酵的条件,以提高普洱茶品质.

A Comparative Study of Microbial Community and Chemical Components Between the Shallow Tray and the Traditional Fermentation Systems of Pu-erh Tea

Traditionally, the system of pile fermentation is used for the fermentation of tons of Pu-erh tea. Such a system has a disadvantage of uneven transfer of heat. In order to improve heat transfer in Pu-erh tea fermentation, the authors have developed a shallow tray fermentation system. In a study reported herein, the microbial community structure and the chemical composition in the two systems were compared so as to evaluate the feasibility of the shallow tray fermentation system. Determination showed that the change laws of chemical compounds were similar in both fermentation systems. However, in the final fermented tea leaves, the contents of water extract, soluble sugars, thearubigins and flavonols were significantly higher and theabrownine was significantly lower in shallow tray fermentation than in traditional fermentation. The structure of microbial communities in the final fermented tea leaves was different. The dominant bacteria in the final fermented tea leaves were Staphylococcus, Bacillus and Kocuria and the dominant fungi were Aspergillus, Blastobotrys and Rhizomucor in pile fermentation. In contrast, the dominant bacteria in the final fermented tea leaves were Bacillus and Erwinia and the dominant fungi were Brunneoclavispora and Aspergillus in shallow tray fermentation. Sensory evaluation indicated that the final fermented tea leaves of both systems were of good quality. In our further work, the condition control of shallow tray fermentation is to be investigated so as to produce better and stable Pu-erh tea products.