Kombucha saborizada com extratos de resíduos agroindustriais: influência do açúcar na fermentação e na microbiota intestinal

Abstract

Kombucha is an oriental beverage obtained from the fermentation of green tea (Camellia sinenses) and sucrose by a consortium of yeasts and bacteria (SCOBY), rich in organic acids, carbon dioxide, and ethanol. Kombucha has specific characteristics and properties that can benefit human health. Its consumption is associated with antioxidant, antidiabetic, anti-inflammatory, anticancer, and antimicrobial effects. This study aimed to investigate how the use of extracts obtained from different agro-industrial waste and different sugar concentrations affect kombucha fermentation and its impact on the intestinal microbiota. Initially, two mother kombuchas were produced, one without sugar (kombucha) and the other with sugar (kombucha_A). The beverages were flavored with sonicated aqueous extract from freeze-dried mango, cashew, and grape waste. Six kombuchas were prepared, three without sugar and three with sugar. Metabolite concentrations varied among beverages, with the highest acetate production in cashew beverages, lactate in mango beverages, and gluconic acid in grape beverages. Ethanol production was within the limits required by Brazilian legislation (ethanol <0.05% v/v). During stability, there was an increase in butyrate concentration, with the highest concentration being in mango kombucha with sugar (2.34 g/L). The sensory profile was used to describe the color, flavor, appearance, and aroma characteristics of the kombuchas. The sensory evaluation used the free profile, with descriptive terminology based on the Network Method and unstructured scales of 10 cm. The participants showed that agro-industrial waste was effective as flavoring agent in the beverages. Regarding the human intestinal microbiota, the evaluation of the fermented inoculum in the presence of the beverages showed an increase in the diversity of microorganisms and species richness in all samples, with emphasis on the kombucha sample without added sugar. In this sample, the genera Bifidobacterium, Eubacterium, Enterococcus, and Lactobacillus had an increase of 33.85%, 12.10%, 7.93%, and 2.97%, respectively, in relative abundance. Only for the samples of kombucha with sugar and cashew kombucha with sugar, the greatest growth was observed in the genera Escherichia shigella (57.85%) and Clostridium XIVa (32.79%). During fecal fermentation, there was consumption of phenolic compounds and production of short-chain organic acids (butyrate and propionate) in the sample fermented with kombucha. However, the samples of kombucha with sugar and cashew kombucha with sugar had a consumption of organic acids by the fecal microbiota. The positive prebiotic index was observed for the sample that did not contain sugar, while the samples with sugar had a negative index. However, the results obtained in this study support the possibility of developing a beverage with reduced sugar and even its elimination. Simulated digestion trials demonstrated that kombucha consumption has the potential to modify the native gut microbiota, strengthening claims about kombucha being considered a prebiotic beverage.