Thin-layer drying and wetting of wheat

Abstract

Abstract The research objectives were to determine accurate thin-layer drying and wetting equations for ‘Katepwa’ wheat. Equilibrium moisture content (EMC) equations for adsorption and desorption were also developed based on the experimental drying and wetting data. The modified Chung-Pfost equation predicted reasonably well the EMC for both adsorption and desorption of wheat. The range of test conditions were: temperature 7.6–35.1 °C; relative humidity 28–92%; air velocity 0.04–0.2 m s−1; and initial moisture content 9.2–16.7% (wet mass basis). Thin-layer drying of wheat was affected by air temperature, relative humidity, and initial moisture content while thin-layer wetting also slightly depended on air velocity. The semi-empirical equation of Page was more accurate than the theoretical diffusion equation with the diffusion coefficient dependent on temperature only.