What is the main biological principle of brewing sweet wine with koji?

Rhizopus strains with high amylase production are often used for fermentation. In addition, it also contains a small amount of alcoholase system and produces ethanol and organic acids [1], which often increases the flavor of brewed products. Sweet wine is made by saccharifying and fermenting steamed rice with sweet wine koji. The flavor and nutrition of liqueur depend on the quality of liqueur koji. Rhizopus and yeast play a major role in sweet wine koji, and Rhizopus is the main saccharifying bacteria. The production of sweet wine mainly uses amylase produced by Rhizopus to decompose glutinous rice starch into monosaccharide, dextrin and a small amount of reducing sugar and oligosaccharide, forming the unique flavor of glutinous rice sweet wine. The research on amylase of Rhizopus liquefaciens is one of the research focuses of distillers and researchers, and it is also an important basis for screening excellent Rhizopus liquefaciens.