Diffusion of Glucose and Ethanol in Corn Grits

Abstract

Effective diffusion coefficients of glucose and ethanol in corn grits were estimated as a factor affecting the velocity of solid-state ethanol fermentation by using the Crank's equation. Experimental results showed values about 1/5 of the molecular coefficient in water. The 90% response time of diffusion was 5 to 10 minutes in well stirred solution. This means that the diffusion rates are evaluated to be larger than the rates of changes in solute concentration, and that effects of concentration distribution of these substances are negligible in the course of conventional solid-state ethanol fermentation of corn grits.