Potential application of <i>Saccharomyces cerevisiae</i> strains for the fermentation of banana pulp

Abstract

This paper aimed at evaluating the fermentation behavior of selected Saccharomyces cerevisiae strains in banana pulp and they were compared with commercial yeast (baker’s yeast) for subsequent production of distilled spirits. Five types of microorganisms were used: Four yeast strains obtained from accredited microbiology laboratories were isolated from domestic cachaça distilleries (UNICAMPV1, UFMG-A905, UFMG-A1007 and UFMG-A1240) and commercial pressed yeast (COMMERCIAL-yeast). The fermentation parameters of the studied S. cerevisiae strains were significantly different. COMMERCIAL-yeast and UNICAMP-V1 strain presented higher ethanol yield and better yeast efficiency in converting total reducing sugars (TRS) into alcohol, with ethanol yields of 83.07 and 94.06%, and yeast efficiency of 90.75 and 96.41%, respectively for UNICAMP V1 and COMMERCIAL-yeast. The higher alcohol contents of 82.26 and 78.05 mg/100 ml anhydrous alcohol were obtained by the UNICAMP-V1 and COMMERCIAL-yeast, respectively. No significant differences in fermentative parameters were observed between COMMERCIAL-yeast and UNICAMP-V1 strain. The UFMG-A1240 strain showed the lowest ethanol yield and therefore not suitable for the production of distilled spirits made of bananas, despite being useful for the production of cachaça. Methanol contents did not significantly vary among the five strains tested, except for UFMG-A1007, which produced significantly higher quantities of 0.19 ml/100 ml anhydrous alcohol. However, higher alcohols contents varied significantly between the five strains tests, with the UFMG-A1007 and UFMG-A1240 strains producing the lowest quantities of higher alcohols (30.04 and 48.69 mg/100 ml anhydrous alcohol, respectively). In conclusion, the S. cerevisiae strains UNICAMP-V1 and the COMMERCIAL-yeast showed better fermentation behavior, did not produce high methanol and higher alcohols amounts, and therefore were recommended for the production of distilled spirits made of banana in pilot-scale plants.

Key words: Yeast, Saccharomyces cerevisiae, alcoholic fermentation, banana spirits.