Mathematical prediction of moisture profile in layers of grain during pre-conditioning

Abstract Wheat grain soaking characteristics were modelled based on Fick's law of diffusion assuming the grain was a composite sphere having a starchy endospermic core and an outer concentric shell of bran. The governing equation in spherical co-ordinate was solved using a finite difference method. From soaking data collected for pearled wheat (starch) and whole wheat (starch and bran), liquid diffusion coefficients of starch and bran are evaluated as 1.91533 × 10−10 and 1.78339 × 10−10 m2/s, respectively at an ambient temperature of 30 °C, by minimising the sum of squared deviation between the observed and predicted soaking results. The developed models for soaking of pearled and whole wheat were capable of predicting the moisture profile as well as the individual component moisture content with time and were found to be in good agreement with experimental data.