Development of bakerns yeast "tokachino" through collaboration of industry, academia and government

Abstract

Eight yeast strains were isolated from samples collected in Hokkaido after enrichment culture with a high concentration of sucrose. Among them, strain AK 46, which was derived from dough containing fermented cherry fruits was identified as Saccharomyces cerevisiae. The nucleotide sequence of the rDNA spacer region from this strain was identical to those from yeasts used for the production of whisky, wine, and bread. Strain S. cerevisiae AK 46 carried only SUC2, which is one of multiple genes that encodes invertase, in contrast to the other baking strains, and its sequences were diverged from those of the corresponding gene found in the other strains. In a comparison of six baking strains, strain AK 46 showed lower leavening ability in dough with and without the addition of 5% sucrose by weight of flour but showed high leavening ability in sweet dough containing 30% sucrose. The activities of enzymes α-glucosidase and invertase, which are related to dough fermentation, were lower than those in the other strains. A baking test showed that strain AK 46 was suitable for breadmaking by various methods. Cells of strain AK 46 were propagated industrially and used for the commercial production of dry yeast called "Tokachino" which is named for the region from which it was isolated.