Kombucha beverage from non-co nventional edible plant infusion and green tea: Characterization, toxicity, antioxidant activities and antimicrobial proper

Kombucha is a beverage based on a sugared medium fermented by a symbiotic culture of bacteria and yeast. The aim of this study was to produce unfermented and kombucha beverages with Malvaviscus arboreus and Camelli a sinensis as substrates, and as sess their physico-chemical characteristics, in vivo toxicities, antioxidant activities and antimicrobial properties. The beverages were prepared from infusions (0.5%, w/v), with sucrose (5.0%, w/ v), kombucha culture (2.5%, w/v), and 1.0% (v/v) of the previously fermented beverage, and incubated at 24 +/- 2 degrees C for 14 days. The results showed that both produced kombuchas are within the physico-chemical and microbiological parameters recommended by the Food and Drug Administration. None of the tested samples showed toxicity from the in vivo model of Galleria mellonella larvae. A significant increase of 14 5% w/v was observed on the total phenolic content of the Malvaviscus arboreus kombucha when compared to its infusion. Green tea and green tea kombucha showed antifungal activity against the pathogenic fungus Paracoccidioides brasiliensis. Green tea was also the only beverage to present antimicrobial activity against all fungi cultures evaluated and against Staphylococcus aureus and Listeria monocytogenes. Thus, it is possible that the type of substrate used in the kombucha production interferes with its bioactive properties. This report shows the potential use of nonconventional edible plant, such as Malvaviscus arboreus, as substrate for kombucha fermentation and for the first time the use of Galleria mellonella larvae as in vivo model of toxicity in the analysis of kombucha.

Automated summary

Two types of kombucha beverages produced from Malvaviscus arboreus and Camellia sinensis met physico-chemical and microbiological standards with no observed toxicity. Malvaviscus arboreus kombucha showed a significant increase in total phenolic content, while green tea kombucha exhibited antifungal and antimicrobial activities.