Honey-kombucha beverage with yerba maté infusion: Development, polyphenols profile, and sensory acceptance

Kombucha is a sweetened beverage made by fermenting a symbiotic consortium of bacteria (generally acetic acid bacteria) and yeasts (SCOBY) in black or green tea, with sucrose as source of carbohydrate. Other herbal infusions, such as yerba maté (Ilex paraguarienses), are used to produce kombucha-like beverages. Honey is a good source of sugar and biologically active components for kombucha-like development. The goal was to develop and characterize a fermented beverage from yerba maté infusion using a kombucha culture, with either sucrose or different types of honey from Apis bees and native Brazilian stingless bees. The fermentation process was studied for up to 20 days, monitoring pH, titratable acidity, reducing sugar and soluble protein, total phenolic compounds, chlorogenic acids, caffeine, and rutin. The sensory acceptance of the honey-kombucha-like beverage was also investigated. As fermentation progressed, the pH decreased, titratable acidity increased, and reducing sugars initially decreased due to SCOBY consumption, followed by an increase due to the conversion of non-reducing sugars to reducing sugars. The concentration of chlorogenic acids increased with fermentation, exceeding 300 μg/mL after 15 days. The aroma and flavor of the kombucha beverage received scores around 5–6 on a nine-point hedonic scale. These scores were linked to the high titratable acidity after the 10th day of fermentation and the “vinegar taste” reported by the subjects. To improve sensory acceptance, the fermentation length can be reduced to up to 10 days, resulting in a beverage with a pleasant fruity and sour aftertaste. However, this strategy may compromise the retention of high polyphenols, which is achieved through longer fermentations of around 15–20 days.