Otimização da fermentação de erva mate adicionada de pitanga preta (Eugenia uniflora l.) com microrganismos da kombucha

Abstract

Kombucha is a beverage fermented by a symbiosis between yeast and bacteria species. The increase in interest for the beverage has been observed due to its detoxifying and antioxidant capacity. The search for new substrates means that yerba mate (Ilex paraguariensis St. Hil.) and black pitanga (Eugenia uniflora) have great potential to be used as raw material in the preparation of kombucha. The leaves of the yerba mate and the fruits of the black pitanga have high levels of bioactive compounds in their composition. Therefore, this work aims to evaluate the fermentation kinetics of kombucha, obtained from the infusion of mate leaves, added with black pitanga pulp, in order to obtain a beverage with higher levels of bioactive compounds, such as acid glucuronic acid (produced in fermentation) and higher antioxidant activity. Fermentation optimization identified the best temperature (25 oC), yerba mate concentration (11.5 g/L) and sugar (130.0 g/L) of the must, to obtain higher levels of total phenols, flavonoids, glucuronic acid, ascorbic acid and higher antioxidant activity (DPPH, ABTS, FRAP). Before addition to the fermentation must, the black pitanga pulp was evaluated. The pulp has 0.83 ± 0.05 g/L of vitamin C and a high concentration of phenolic compounds; as well as antioxidant activity and antiglycemic activity. Therefore, fruits have a high potential to be used in new products and are associated with the demand for foods with exotic and native flavors. In addition, black pitanga can be an alternative for flavoring yerba mate kombucha. Through the study of fermentation kinetics, it was possible to visualize that fermentation promoted an increase in antioxidant activity in the beverage, and the addition of black pitanga added phenolic compounds, where anthocyanins were preserved during the fermentation process for 15 days. Following the legal parameters for kombucha production, the ideal fermentation time for the yerba mate infusion was 10 days and for the fermented product with black pitanga was 7 days. Black pitanga juice added different bioactive compounds from those from those found in yerba mate, promoting an increase in anti-glycemic activity. In this way, yerba mate associated with the fruits of the black pitanga is a good substrate for fermentation and can be used in the preparation of beverages with kombucha microorganisms.