Dados do Trabalho

Título

YEAST SELECTION AND EVALUATION OF MICRO FERMENTATIONS FOR THE PRODUCTION OF CATHARINA SOUR BEER

Introdução

Catharina Sour beer is the first Brazilian style, which uses lactic acid bacteria and yeast in fermentation, besides tropical fruits that differentiate the production and sensorial characterization of this beer. As it presents study potential, this work aimed to select and evaluate potential starter cultures for Catharina Sour beer production.

Material e Métodos

Eight yeasts (Saccharomyces cerevisiae) from the Agricultural Microbiology Culture Collection (CCMA) were subjected to fermentation on different carbohydrates, pH tolerance, and flocculation tests. Then, the selected yeasts were used in micro fermentations in 100 mL must (18 ºC for seven days) to evaluate parameters of ºBrix, pH, ethanol concentration (by HPLC), and microbial population. The lactic acid concentration (by HPLC) was assessed in fermentation with the Lactiplantibacillus plantarum CCMA 0743 for 48 hours.

Resultados e Discussão

The CCMA 1746 strain showed slow fermentation for maltose and sucrose (14 days), making its use unfeasible. In the pH tolerance test, strains CCMA 0188 and CCMA 0543 showed a significant decrease in population (Scott-Knott test, p < 0.05), making them less promising for Sour beer production. The yeasts CCMA 0186, 0137, and 0018 were classified as “non-flocculant” and unattractive for this biotechnological process. According to the results, the CCMA 0233 and CCMA 0200 strains were selected for micro fermentations. Strains CCMA 0233 and CCMA 200 showed an increase in population throughout fermentation, with a decrease in ºBrix and an increase in ethanol concentration over 168 hours (CCMA 0200 - 43.74 g/L and CCMA 0233 - 46.99 g/L). Fermentation with L. plantarum CCMA 0743 can be carried out in 24 h, as the production of lactic acid between 24 and 48 h did not differ statistically (9.51 g/L and 9.56 g/L), with a decrease in pH (3.38 and 3.32, respectively).

Conclusão

The yeasts S. cerevisiae CCMA 0200 and 0233 proved suitable for Catharina Sour beer production by maintaining the population during fermentation, ethanol production for the style, and tolerance to low pH. Furthermore, the bacteria L. plantarum CCMA 0743 reduced the pH and produced sufficient lactic acid within 24 h. Therefore, combining this bacterium with selected yeasts is favorable for Catharina Sour beer production.