SELECTION OF A NOVEL BAKING STRAIN FROM THE TORULASPORA YEASTS

Among the yeasts belonging to the genus Torulaspora, T. pretoriensis IFO 10218 was selected as a maltose-fermenting strain that could leaven dough containing 5% glucose as high as commercial baking strains. The freeze-thaw resistance of this strain in the dough was higher than that of Saccharomyces cerevisiae FL 2209 isolated from commercial compressed yeast. Since the cells of IFO 10218 readily sedimented in their suspension, a dispersing mutant, YK-1, was induced. When YK-1 was cultured in the presence of NaCl, leavening abilities were reduced, unlike FL 2209. Alpha-Glucosidase activity of YK-1 cells grown on maltose increased slightly, resulting in partly improved leavening ability in the dough without addition of sugar. YK-1 was shown to be a candidate applicable to breadmaking by not only usual method but also the frozen-dough method.