ONLINE CONTROL OF THE SAKE MASHING PROCES S BY TRAJECTORY CONTROL OF THE ETHANOL-PRODUCTION RATE

A new method for controlling the sake mashing process was developed. F irst, the trajectory of the ethanol production rate was calculated fro m the ethanol concentration and rice liquefaction rates using the diff erential equations for ethanol production and the liquefaction of rice or the curve fitting method. Control of the ethanol production rate t o trace the set trajectory was performed by manipulating the temperatu re. When the initial glucoamylase activity is less than 55-60 units/g- rice, the standard deviations for the ethanol concentration and sake m eter (density) in the controlled sake mash must be 0.16% v/v (1.26 g/l ) and 2.1 (0.0015 d15), respectively. The success of this control meth od appears to be due to the uniqueness of the rate limiting step, liqu efaction, which results in glucose limitation later in the process.