Effect of microbial fermentation on caffeine content of tea leaves.

Effect of microbial fermentation on caffeine content of tea leaves.

Wang X1, Hu S, Wan X, Pan C.
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Caffeine is widely used in the food and pharmaceutical industries. For safety concerns, natural caffeine is preferred over synthetic products despite of its high cost. To explore more economical methods of acquiring natural caffeine, we adopted a microbial fermentation technique to increase the caffeine content of tea leaves. Our studies showed that the caffeine content in tea leaves increased reasonably after treating leaves with microorganisms for a period of time (i.e. orthodox pile-fermentation), and the amount of caffeine content increase varied significantly between black and green teas (27.57% and 86.41%). These results suggested that the change of caffeine content in tea leaves during the pile-fermentation depended not only on the growth and reproduction of microorganisms, but also on the tea composition.


content during the fermentation of tea with microorganisms


The tea caffeine content had previously been shown to increase reasonably after being treated with mixed microorganisms for a period of time. In this study, single microorganisms were used in the fermentation of black and green teas in order to find which microorganism has the best effect on increasing the caffeine content. The results demonstrated that molds fermentation increased the caffeine content, but yeasts fermentation decreased the caffeine content. Among the three molds in this study, Aspergillus niger van Tieghem has the most remarkable effect, and the caffeine content in dry green tea increased from an initial 3.47% to 9.63%. The increase rate was 177.5% on the 16th day. Furthermore, the changes of caffeine and theophylline were of a similar trend. Possibly theophylline instead of theobromine is the precursor of caffeine in the living microorganisms. The new biosynthetic route is different from that in tea plants.

Effect of Fermentation on Caffeine Content in Tea


Fermentation is an indispensable process for making some types of tea. Many tea lovers may know that fermented tea, like black tea and pu-erh tea contains higher caffeine than unfermented tea like green tea. In this article, we will further verify this conclusion by analyzing some experimental data.

Kombucha Caffeine Content

Kombucha is generally considered to have about ⅓ the amount of caffeine as the tea it is made with, so for example black tea, which might have 30-80mg of caffeine per cup may yield a glass of Kombucha with 10-25mg of caffeine. Green tea Kombucha might have just 2-3mg of caffeine.


Kombucha & Caffeine Explained

Caffeine, often called America’s favorite drug, can have negative (and sometimes hilarious) effects on the body and the nervous system. Yet significant amounts of this pharmacological agent occur naturally in the 2 most popular beverages in the world (besides water), tea and coffee. Large doses are added to soft drinks and even bottled water. Like many good, naturally occurring substances found in nature, commercial production has perverted our relationship with caffeine, leaving us addicted or scared or both.

Don’t Let It Get Overly Sour

Bottle your kombucha tea when it’s slightly sweet. It will continue to ferment in the fridge. When it turns too sour, that means the yeasts and bacteria have run out of food and your kombucha will go flat. This is really important if you’re looking for fizzy kombucha. Those microbes need the sugars to consume and make probiotics and lots of carbonation. Remember, the sugar in the tea is for those good bacteria and yeasts and not for you.