Abstract:

Fresh tea leaves from different tea cultivars, Qianmei 419, Qianmei 502,Qianmei 601,Qianmei 809 and
Fudingdabaicha were fermented in a laboratory-made aerobic fermentor to produce black tea in comparison to natural
fermentation. Changes in sensory quality were recorded at 15-min intervals during the fermentation, and leaf temperature
and pH were measured as well. The results showed that during the early stage of aerobic fermentation, the leaf temperature
went up quickly to a level higher than that of natural fermentation. Aerobic fermentation accelerated the color alteration of
tea leaves to red and facilitated the formation of characteristics aroma. During the fermentation process, the pH value of
fermented tea leaves showed a downward trend under both conditions, but decreased faster under aerobic condition. The
results of sensory evaluation showed that the overall quality of black tea from aerobic fermentation was as good as that from
natural fermentation.

Key words: black tea, aerobic fermentation, sensory quality, leaf temperature, pH value