Food & Beverages

Biography

Biography: Waldir Desiderio

Abstract

The fermentative behaviour of Candida zemplinina Y.01667 and Y.01670 were evaluated in order to find their application in beer fermentation. These strains were compared with a commercial lager yeast Saccharomyces cerevisiae S-23. Experiments were carried out under static conditions at different fermentation temperatures in Erlenmeyer flasks containing different concentrations of glucose syrup, a sugar source commonly used as adjunct in brewing. Results showed that both Candida yeasts can ferment well at 14°C and 20°C and in medium containing 16 %w/v of carbon source. The highest rate of ethanol production was obtained with Candida zemplinina Y.01670 (0.56 g.h-1 and 1.68 g.h-1) when fermented at 14°C and in medium containing 16 %w/v of sugars. Saccharomyces cerevisiae S-23 in this case attained values of 0.81 g.h-1 and 2.13 g.h-1 respectively. Ethanol productivities were higher in fermentations with Candida zemplinina Y.01667 (0.24 g.l-1.h-1 and 0.32 g.l-1.h-1) and Candida zemplinina Y.01670 (0.25 g.l-1.h-1 and 0.38 g.l-1.h-1) carried out at 20°C and with medium containing 16 %w/v of carbon source respectively. The specific growth rates of both Candida strains were higher than that of Saccharomyces cerevisiae S-23 (0.018 h-1 and 0.038 h-1) when fermented at 14°C and 20°C respectively. These Candida strains are less flocculent and also sediment slowly compared to Saccharomyces cerevisiae S-23. At the end of the fermentation periods the concentration of viable suspended cells was typically higher than 1 x 106 cells.ml-1. These yeast strains could be used to brew special beers where adjuncts from fruit sources are used.