Enhancement of the phenolic compounds and antioxidant activities of Kombucha prepared using specific bacterial and yeast

Abstract

The symbiotic culture of bacteria and yeast (SCOBY) encompasses a diverse array of microorganisms that play a pivotal role in the biochemical transformations during Kombucha fermentation. This study aims to investigate how various combinations of acetic acid bacteria (AAB) and specific yeast strains influence SCOBY formation and the biochemical characteristics of Kombucha. Thirteen combinations of AAB and yeasts formed SCOBY. The pH of Kombucha decreased to 2.31, and titratable acidity content increased to 20.76 g/L. Acetic and gluconic acid contents of Kombucha were 1.96 g/L and 6.9 g/L, respectively. The total phenolic and flavonoid contents increased by 3.53- and 5.2 fold, whereas the condensed tannin content decreased by 31.3 fold. Chlorogenic, p-coumaric, and ferulic acids were newly detected. Catechin, epicatechin, caffeine, caffeic acid, gallic acid, and rutin contents in Kombucha were increased. The antioxidant activity of Kombucha was enhanced up to 2.88 fold. The use of AAB and yeast has potential value in the industrial production of Kombucha.