Resumo

Yakupa is a spontaneously fermented beverage produced by indigenous Juruna people, who inhabit the Indigenous Xingu Park, Mato Grosso, Brazil. This non-alcoholic beverage is consumed daily by children and adults and is classified within refreshing cauims. In this work the microbial dynamics involved in yakupa fermentation were investigated by culture dependent methods (plating on Agar MRS for lactic acid bacteria and Agar YEPD for yeasts) and by PCR-Denaturing Gradient Gel Electrophoresis (PCR-DGGE). The metabolites produced during fermentation process were assessed by liquid and gas chromatography. The lactic acid bacteria (LAB) population was higher than yeast in the beginning of fermentation (5 log CFU⁄ mL and 3 log CFU⁄ mL, respectively) and after 36 h both population increased reaching 7 log CFU⁄ mL, remaining constant until 60 h. Culture dependent and independent methods in combination identified the bacteria Lactobacillus fermentum, L. plantarum, Weissela cibaria and W. confusa, and yeasts Saccharomyces cerevisiae and Pichia kudriavzevii. Maltose (41.2 g⁄ L), ethanol (6.5 g⁄ L) and lactic acid (7.8 g⁄ L) were the most abundant compounds identified by High Performance Liquid Chromatography (HPLC). Aldehydes, acids, alcohols and esters were identified by Gas Chromatography (GC-FID). By the metabolites and PCA analysis we may assign the beverage’s flavor to the microbial metabolism. Heterolactic LAB and S. cerevisiae were dominant in yakupa fermentation, being responsible for the organoleptic characteristics of the final product. In conclusion, the dynamic of yakupa spontaneous fermentation demonstrated the dominance of heterolactic LAB species, although a significant yeast population was observed. This work was the first time that the microbial dynamics and physicochemical parameters were investigated in the yakupa beverage and it may contribute to the future selection of starter cultures to perform yakupa fermentations.