Antioxidant and antibacterial activity of a beverage obtained by fermentation of yerba‐maté ( <i>Ilex paraguariensis</i> ) with symbiotic kombucha culture

Abstract

This study aimed to characterize yerba-maté kombucha by showing its oxidative stress inhibitory property with Saccharomyces cerevisiae yeast as the model and to determine its antibacterial activity against Staphylococcus aureus and Escherichia coli. Different yerba-maté concentrations and fermentation temperatures were analyzed by an experimental design. Sucrose was used as the carbon source and green tea kombucha was used as the control. Yerba-maté beverage, which was fermented for 12 days had pH levels between 1.8 and 2.3; acidity from 4.8% to 6.0% acetic acid; total reducing sugars between 15.9 and 23.1 g/L; and total phenolic compounds (TPC) between 444.2 and 844.8 mg/L eq. gallic acid. Antioxidant activity, measured by the ABTS+ method, was from 16.1% to 31.3% higher than unfermented extracts. Yerba-maté kombucha exhibited antibacterial activity and was also effective to prevent the oxidative stress in S. cerevisiae. Practical applications Yerba-maté kombucha contains bioactive compounds that have potential applications in the food industry. Polyphenols are the main compounds found in yerba-maté kombucha, whose properties, such as antioxidant activity demonstrated in in vitro and in vivo tests, are potentially beneficial to health. Organic acids produced during fermentation to inhibit bacterial growth increase shelf life of the beverage and may be used to preserve other food. Thus, due to its significant potential, this study aimed to evaluate different yerba-maté concentrations and fermentation temperatures to obtain kombucha with high bioactive properties.

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