Abstract:

As important substances present in tea, purine alkaloids are often employed in medicine and health care as well
as drinks. The kinds and contents of purine alkaloids are potentially changed during microbial fermentation of tea. After
reviewing recent literature regarding the association of microorganisms with the metabolism of purine alkaloids in fermented
tea, this article finds that different strains, when used individually to ferment tea, have different effects on the kinds and
contents of purine alkaloids. Cephalosporium acremonium can substantially enhance caffeine contents in tea, Aspergillus
fumigatu, Lactobacillus, and acetic acid Lactobacillus have little impact on the contents purine alkaloids, and yeast and
Aspergillus sydowii NRRL 250 can reduce caffeine contents. However, the effect of Aspergillus niger on purine alkaloid
metabolism remains controversial. In addition, a trade-off relationship between caffeine and theophylline exists during tea
fermentation.

Key words: tea, microorganism, purine alkaloids, caffeine, metabolism