The antioxidant and starch hydrolase inhibitory activities of Chinese black tea, oolong tea,
green tea, Sri Lankan black tea and Rooibos tea fermented with the ‘tea fungus’ (Kombucha)
for 7 days were investigated along with the pH, titratable acidity (TA) and colour. The pH
statistically significantly decreased from day 1 onwards of the fermentation (P < 0.05) as compared
with the unfermented teas. A statistically significant increase (P < 0.05) of the TA was
observed from day 5 onwards.The colour of all five teas was observed to get lighter. Rooibos
tea, Sri Lankan black tea and green tea had statistically significant increases (P < 0.05) in
the total phenolics content and antioxidant activities from day 1 onwards of the fermentation.
This was further supported with the increases in the polyphenol contents in all fermented
teas. All five Kombucha teas inhibited α-amylase better than α-glucosidase.