The goal of this study was to determine the effects of initial moisture content and heating rate on the drying kinetic parameters of wheat under non-isothermal conditions. Wheat (OAKES) samples at initial moisture contents of 20.7%, 18.5%, 16.8%, and 14.8% wet basis (w.b.) were dried using a thermogravimetric analyzer. The analyzer was set at five heating rates (2, 3, 4, 5 and 10oC/min) to determine the drying kinetic parameters, i.e., activation energy, of the heated samples from room temperature of 30°C to 170oC. The experimental moisture ratio data were fitted to the four empirical models, namely Page, Newton, Logarithmic, and Henderson models. The goodness of fit criterion was used to determine the best-fitting model.
Heating rate and initial moisture content affected the activation energy required for drying wheat. Increasing the heating rate expedited the drying curve. The heating rate of 10°C/min for wheat at an initial moisture content of 14.8% w.b. resulted in the greatest activation energy of 28.174 kJ/mol. The heating rate of 2°C/min for wheat at an initial moisture content of 20.7% w.b. resulted in the lowest activation energy of 14.760 kJ/mol. The Logarithmic and Henderson models were adjudged as best fit models for the entire drying curves by R2, RMSE, and X2. This study highlighted that the energy required to dry wheat from 20.7% w.b. to acceptable safe level could be minimized by reducing the heating rate
