Polyphenols in kombucha: impact of infusion time on extraction and investigation of their behavior during “fermentation”

Abstract

Kombucha is a non-alcoholic beverage made of sugared tea that is transformed by a symbiotic consortium of yeasts and bacteria. Polyphenols are expected to be responsible of several health benefits attributed to kombucha consumption, among other metabolites. This study investigated the impact of tea infusion time and of kombucha “fermentation”, on total phenolic content, proanthocyanidins concentration and the color. It was determined that pH decrease during fermentation was the origin of kombucha color loss. Moreover, fermentation impacts the profile of black and green tea polyphenols more than infusion time between 30 minutes and 1 hour. Results suggest a significant release of phenolic compounds during “fermentation” possibly caused by the hydrolysis of molecular bounds, such as gallate ester bounds.