Seleção de leveduras não-Saccharomyces e avaliação da produção de aromas durante as fermentações na forma pura, mista e sequencial em mosto sintético

Abstract

The use of yeasts in fermentation processes is important, because in addition to the production of ethanol and carbon dioxide, they contribute significantly to the production of aroma compounds. Yeasts from the non-Saccharomyces group have been receiving more space due to the potential to increase the generation of aromatic molecules, especially esters and alcohols, which contribute positively to the aroma of fermented drinks. Thus, the objective of the present study was to select a nonSaccharomyces yeast capable of generating aromas and to evaluate its production potential of esters and alcohols during fermentations in pure, mixed and sequential form in synthetic must. Of the 32 strains of non-Saccharomyces yeasts surveyed, UMSC 19.11 was selected due to its ability to produce esters, especially phenethyl acetate, in addition to the feasibility for carrying out fermentations in synthetic must. This strain was inoculated in pure, mixed and sequential form in synthetic must and the esters and alcohols were evaluated after 3, 7 and 10 days of fermentation at 20 ºC and 25 ºC. Thirteen volatile compounds, including 8 esters and 5 alcohols have been identified. Phenethyl acetate in pure fermentation with the non-Saccharomyces strain, at 25 ° C for 3 days, was expressively produced, in mixed fermentation the highlight was the production of isopentanol and phenethyl alcohol and in sequential fermentation, hexanoate and ethyl octanoate. However, ethanol production was higher in fermentations using the S. cerevisiae strain. In general, the temperature of 25 ° C showed that the acetyl esters group was more favorable and the temperature of 20 ° C for ethyl esters. The results of this work indicated that the non-Saccharomyces yeast, identified as Hanseniaspora opuntiae, demonstrates its capacity to contribute positively to the generation of aromas in synthetic must, which corroborates the continuity of its study and its possible application in fermented beverages.