Avaliação microbiológica, fisicoquímica e bioativa da bebida kombucha fermentada com Scoby liofilizado

Abstract

Kombucha is a fermented drink made from the leaves of the Camellia sinensis plant, an elixir rich in organic acids, minerals and vitamins, which are produced by a symbiotic community of bacteria and yeasts, referred to as SCOBY (Symbiotic Culture of Bacteria and Yeasts) . SCOBY is the main source for making the drink, and, being a delicate biofilm, it is subject to restrictions, which can compromise the shelf life and nutritional attributes of the drink. Its commercialization in its natural state leaves room for drying techniques, which aim to preserve the compounds and properties, guaranteeing quality and food safety. In order to explore this possibility, the freeze-drying technique was applied to the kombucha SCOBY, aiming to evaluate its rehydration potential in a new green tea. The study analyzed the characteristics of the material after the drying process and the drink fermented with it. Soluble solids, titratable acidity, pH, phenolic compounds, flavonoids, anthocyanins, reducing sugars, antioxidant and microbiological activity of kombuchas produced with natural SCOBY and freeze-dried SCOBY with and without starter tea were evaluated in order to investigate the influence of this process. in the fermentation and freeze-drying of the material for subsequent reconstitution. The results revealed that beverages fermented with starter tea had better cellular results, highlighting the importance of this component for the fermentation process. There was a reduction in the count of microorganisms after the dehydration process, reaching significant levels, ranging between 4x104 and 2.5x106 CFU.ml, which indicated moderate resistance to the process. The pH remained within regulatory standards, however, there was a low consumption of soluble solids (8.96°Brix), which is specifically the main substrate for microorganisms, as well as a low acidity (0.15%), presenting a reduced productivity of the enzymes responsible for the production of organic acids. Regarding antioxidant activity, there was an increase in the levels of flavonoids and anthocyanins (0.93±0.07 and 0.11±0.03), however, phenolic compounds and the absorption capacity of the ABTS radical were greater after freeze-drying of the SCOBYs (20.73±0.2 and 891.3±0.2), demonstrating an increase in the antioxidant content of the material. The results of this study highlight the possibility of cellular development after SCOBY freeze-drying, paving the way for potential commercial applications of innovation in the field of kombucha production.