title: Water-absorption rate equation of rice for brewing sake.
abstract: This study was undertaken to analyze the kinetics of water absorption and to derive an equation for the rate at which water is absorbed by rice for brewing sake. We used two rice varieties: Gin-oumi, commonly used as a staple food, and Gohyakumangoku, a variety used particularly for brewing sake. The water-absorption rate equations of Gin-oumi and Gohyakumangoku were postulated based on the following equations. For Gin-oumi (water content, 11.5%), dx/dtheta=k(1-x)(n), n=1, k=(2 x 10(-9))exp(0.0604 x (t+273.15)). For Gohyakumangoku (11.5%), dx/dtheta=k(1-x)(n)(x+a), n=1, a=0.29, k=(2 x 10(-8))exp(0.0534 x (t+273.15)). Here, x, theta (min), and t ( degrees C) are the water absorbing ratio, time, and temperature, respectively. The result shows that the values of the temperature-dependence parameter k (min(-1)), as well as its curves, are different; a typical rice grain has a monotonically smooth curve, whereas that suitable for sake brewing has an S-shaped curve.
authors.affiliation: Kizakura Co., Ltd., 223 Shioyamachi, Fushimi-ku, Kyoto 612-8242, Japan. mizuma@kzkappa.co.jp
authors.forename: Tomochika
authors.initials: T
authors.lastname: Mizuma
authors.forename: Akiko
authors.initials: A
authors.lastname: Tomita
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kitaoka
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Kiyokawa
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Wakai
mesh_terms: D000042:Absorption; D005285:Fermentation; D007700:Kinetics; D008954:Models, Biological; D008956:Models, Chemical; D012275:Oryza / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D014920:Wine / Q000382:microbiology*
chemical_list: D014867:Water