Effect of<i>koji</i>starter on metabolites in Japanese alcoholic beverage sake made from the sake rice<i>Koshitanrei</i>

Abstract

In sake brewing, the steamed rice is used in 2 ways, added to sake-mash and making rice<i>-koji</i>. Rice-<i>koji</i> is made from the steamed rice by using <i>koji</i> starter, and its quality is an important determinant of the aroma/taste of sake. The sake rice <i>Koshitanrei</i> (KOS) was developed in Niigata Prefecture by crossing 2 sake rice varieties, <i>Gohyakumangoku</i> and <i>Yamadanishiki</i>. Recently, we reported the characteristic components/metabolites in sake made from KOS by conducting metabolome analysis using UPLC-QTOF-MS. In this study, to investigate the effect of <i>koji</i> starter and sake rice cultivars on the sake metabolites, we performed small-scale sake-making tests using the above 3 rice cultivars and 3 <i>koji</i> starters. Finally, we demonstrated that some of the characteristic components/metabolites of sake from KOS are affected by the <i>koji</i> starter. Thus, in addition to rice cultivar, <i>koji</i> starter plays an important role for establishment/maintenance of the quality of the final product.