The role of rice α-glucosidase on kutikami-sake making

Abstract

To examine the role of rice-α-glucosidase on kutikami-sake brewing, a traditional sake making method, we made two test solutions with chewed uncooked rice and cooked rice. In the solution with chewed uncooked rice, 5% of glucose with no maltose was produced, whereas in the solution with chewed cooked rice 0.8% of glucose with 5% of maltose was produced after 24 hours incubation. This difference was mainly due to the glucose for mation from maltose derived from α-glucosidase contained in uncooked rice, the maltose being produced by α-amylase in saliva. The lactate produced by microorganisms caused pH decrease to around 4, an optimum pH for α-glycosidase, and aided in the extraction of α-glucosidase from unncooked rice. From the above results, it was determined that unncooked rice was used as a material in kutikami-sake brewing.