MATHEMATICAL PREDICTION OF MOISTURE PROFILE IN LAYERS OF GRAIN DURINGPRECONDITIONING

Wheat grain soaking characteristics were modelled based on Fick's law of diffusion assuming the grain was a composite sphere having a starch y endospermic core and an outer concentric shell of bran. The governin g equation in spherical co-ordinate was solved using a finite differen ce method. From soaking data collected for peal-led wheat (starch) and whole wheat (starch and bran), liquid diffusion coefficients of starc h and bran are evaluated as 1.91533x10(-10) and 1.78339x10(-10)m(2)/s, respectively at an ambient temperature of 30 degrees C, by minimising the sum of squared deviation between the observed and predicted soaki ng results. The developed models for soaking of pearled and whole whea t were capable of predicting the moisture profile as well as the indiv idual component moisture content with time and were found to be in goo d agreement with experimental data. (C) 1997 Elsevier Science Limited.