The formation of β-damascenone in sweet potato shochu

Abstract

The formation of β-damascenone during shochu manufacture was investigated by quantifying β-damascenone at each stage of manufacturing. Steamed sweet potato has a low level of free β- damascenone (0.02-0.1 μg/g). During fermentation, β-damascenone was produced in small quantities that were degraded by yeast. Thus, the second mash accumulates little free β-damascenone (approximately 17 μg/L). The concentration profile in the fractionated distillate showed that β-damascenone was produced during heating. Most β-damascenone in shochu was formed during distillation, not during steam heating and fermentation. It is suggested that the level of β-damascenone in shochu could be increased by reducing the pH of the second mash and prolonging the distillation period. Sweet potato cultivars differed in total free and hydrolyzed β-damascenone content and there was a strong association between each cultivar and its shochu β-damascenone content. The selection of the sweet potato cultivar is important for determining the quantity of β-damascenone in a shochu brew. © 2011 The Institute of Brewing & Distilling.