Production and characteristics of traditional alcoholic beverage made with sweet potato as the saccharifying agent

Abstract

Efforts were made to reproduce the traditional Japanese alcoholic beverage, miki using cooked rice and mashed raw sweet potato tubers as the saccharifying agent. The resulting miki-like alcoholic beverage contained 5-6% ethanol (v/v); it had a pleasant aroma but a sour taste with faint bitterness. With increased amounts of raw sweet potato added to the initial mash, the concentrations of higher alcohols, esters and bitter compounds in the miki increased. Oligosaccharides, including maltotetraose and maltopentaose, were detected in the miki made with higher concentrations of raw sweet potato mash. Miki, a previously uncharacterized, traditional, Japanese alcoholic beverage was therefore produced without the enzymic activities of germinating seeds, such as malt, or a fungal starter, such as koji.