Mechanism of aroma production in Japanese sake

Sake contains many components of tastes and aroma. Especially aroma is the characteristic, important factor for the first impression of sake. “Ethyl caproate”, an apple-like flavor, and “ isoamyl acetate”, a banana-like flavor, are the representative components for the fruity aroma “Ginjo-ka”. The sake yeasts produce each aroma during fermentation, the production mechanisms have been elucidated recently. Ethyl caproate is biosynthesized via fatty acid production pathway, and isoamyl acetate is biosynthesized via amino acid production pathway.The breeding methods for a yeast producing a large amount of aroma have been developed, and the industrial brewing yeasts have been actually used for brewing of sake.