Abstract:

The effect of different levels of xylose addition (0.2%–0.8%) on microbes, polyphenol oxidase activity, physical
and chemical properties and organoleptic quality of Pu-erh tea during the pile-fermentation process was investigated in a
simulated laboratory environment. The results showed that the average pile-fermentation temperature was significantly higher
upon xylose addition at 0.8% and 0.6% compared with the control. Mould quantity at the early stage of fermentation and the
maximum polyphenol oxidase activity were positively correlated with xylose concentration. The changes of polyphenols and
catechins were also accelerated when compared with that of the control and positively correlated with xylose concentration.
However, theaflavin was significantly negatively correlated with xylose concentration with a correlation coefficient of
－0.492. By adding 0.8%, 0.6% and 0.4% xylose the fermentation time could be shortened to 18–19 d, 19–21 d and 21–23 d,
respectively, compared with 24 d for the control. The tea fermented with the addition of xylose was much sweeter and had a
stronger aroma than the control.

Key words: Pu-erh tea, xylose, pile fermentation