Kombucha Beverage from Green, Black and Rooibos Teas A Comparative Study Looking at Microbiology,Chemistry and Antioxidant Activity
Francesca Gagga, Loredana Baffon, Michele Galiano, Dennis Sandris Nielsen, Rasmus Riemer Jakobsen, Josue Leonardo Castro-Meja, Sara Bosi, Francesca Truzzi, Federica Musumeci, Giovanni
Kombucha is usually obtained from the fermentation of black or green tea by a consortium of acetic acid bacteria and yeasts. In this study, kombucha was prepared from the same starter consortium using green and black teas as well as, for the first time, an infusion of rooibos leaves (Aspalathus linearis). Microbial diversity was analysed during fermentation both in the biofilm and in the corresponding kombuchas, using culture-dependent and -independent methods. Polyphenols, flavonoids, ethanol, and acids were quantified, and anti-oxidant activities were monitored. All of the Kombuchas showed similarity in bacterial composition, with the dominance of Komagataeibacter spp.
Beta diversity showed that the yeast community was significantly different among all tea substrates, between 7 and 14 days of fermentation and between biofilm and kombucha, indicating the influence of the substrate on the fermenting microbiota. Kombucha from rooibos has a low ethanol concentration (1.1 mg/mL), and a glucuronic acid amount that was comparable to black tea. Although antioxidant activity was higher in black and green kombucha compared to rooibos, the latter showed an important effect on the recovery of oxidative damage on fibroblast cell lines against oxidative stress. These results make rooibos leaves interesting for the preparation of a fermented beverage with health benefits.
Keywords: acetic acid, antioxidant, black tea, ethanol, glucuronic acid, green tea, ph, polyphenols, stress, time
Citation: Nutrients , 11, 1; doi:10.3390/nu11010001 http://dx.doi.org/10.3390/nu11010001
Study Mailing Address:
Department of Agricultural and Food Sciences (DISTAL), Alma Mater Studiorum-Universit di Bologna,
viale Fanin 42, 40127 Bologna, Italy
Date Updated: March 10, 2020