HYBRIDIZATION OF BAKERS-YEAST BY THE RARE-MATING METHOD TO IMPROVE LEAVENING ABILITY IN DOUGH

Saccharomyces cerevisiae MA233 is a diploid strain that is available for breadmaking by the frozen-dough method but it has lower leavening ability than commercial Bakers' yeasts in dough with no sugar or a small amount of sugar. To improve baking quality, MA233 was hybridized with YOY34, a haploid derived from a commercial baking strain, by the rare-mating method. The hybrid YOY671 exhibited MAL-constitutive phenotype of α-glucosidase, resulting in an increased rate of CO2 production from the dough without addition of sugar. YOY671 had a higher leavening ability in the dough containing 5% to 30% sucrose (based on the weight of flour) than MA233. Freeze-thaw resistance of YOY671 in dough was higher than that of YOY34, but less than that of MA233. © 1990.