Effect of Rice Germ Addition to Sake Mash on Aroma Components of Sake

Study on the Brewing of Sake wkth Excellent Taste and Flavor (Part IV)

Abstract

Three sake brewings (No.1 control, No.2 rice germ added, No.3 Mg²⁺, K⁺, and PO₄^3- added) were carried out and changes in aroma components during fermentation were examined. Alcohol acetyltransferase activity and ATP contents of yeast cells were also measured. Contennts of i-AmOH and i-AmOAc, which are recognized to be important aroma components, were gradually increased in progress of fermentation. Sake (No.2) brewed by rice germ addition had higher i-AmOH content (279. 2 ppm), whereas sake (No.3) brewed by inorganic ion addition had almost same content (200. 3 ppm) compared with control sake (211. 1 ppm). Changes in tyrosol and tryptophol contents were also similar to i-AmOH. i-AmOAc contents of sake (No.2 6. 67 ppm, No.3 4.38 ppm) brewed by rice, germ or inorganic ion additions were higher than control sake (No.1 3. 88 ppm). No correlation was observed between changes in alcohol acetyltransferase activity and i-AmOAc formed during fermentation.