Characteristics of different brewer’s yeast strains used for non-alcoholic beverage fermentation in media containing different fermentable sugars

Fermentation characteristics of four strains of brewer's yeast (Saccharomyces cerevisiae strain 70424, S. rouxii strain 2535, S. rouxii strain 2531 and Saccharomyces ludwigii strain 3447) in Yeast Moldbroth containing four different fermentable sugars (glucose, fructose, maltose, or sucrose) were studied. The aim was to consider the suitability of different strain/sugar treatments for the production of non-alcoholic beer as well as to devise treatments resulting in greatest growth rate of yeast cells. Experimental parameters were yeast cell growth, ethanol production, pH drop, and changes in fermenting media attenuation (°Pl), during a 48 h fermentation period. Fermentation was performed at 24°C using periodic aeration practice. For S. cerevisiae, the greatest growth rate was achieved in presence of sucrose. The maximum and minimum ethanol contents at the end of fermentation were related to sucrose(0.94% V/V) and glucose-containing (0.4% V/V) treatments, respectively. In the case of S. ludwigii, fructose stimulated the highest growth rate and the maximum and minimum ethanol contents at the end of fermentation were observed in sucrose(0.49%), and maltose-containing (0.04%) treatments, respectively. For S. rouxii 2535, highest growth rate was observed in the presence of fructose/glucose. The maximum and minimum ethanol contents belonged to the fructose/glucose(~ 0.40) and maltose/sucrose-containg (~ 0.01%) treatments, respectively. In the case of S. rouxii 2531, glucose and to lesser extent, fructose led to the highest growth rate and the maximum and minimum ethanol contents were observed in glucose (0.01%) and maltose/sucrose (0.00%) treatments, respectively. Applying different strains of Saccharomyces in presence of different types of sugars caused various fermentation characteristics especially with regard to growth rate and ethanol production.