An Investigation on Drying of Millets in A Microwave Oven

Finger millet (Eluesine coracana) and foxtail millet (Setaria italica), are highly nutritious minor millets and hence is used in most of the staple foods. The present study was to estimate the thin layer drying characteristics of foxtail and finger millet and developing a thin layer model which adequately fits the data. Foxtail and finger millet with an initial moisture content of 0.314 and 0.313 (kg moisture/kg dry solid) respectively, were dried in a domestic microwave oven at different microwave output powers ranging from 180 to 900W. The data were fitted to different thin layer models and the logarithmic model was found to best describe the drying behavior of the millets among the other models. The experimental moisture ratio values were compared with that predicted from the logarithmic model and was found to be in good agreement. Also, effective diffusivity was calculated by using Fick’s law, which varied from 2.4 *10 to 5.87 *10 m/s and 1.786*10 to 5.14*10 m/s for finger millet and foxtail millet respectively. The values of effective diffusivity were increased with microwave output powers. KeywordsFoxtail millet, Finger millet, microwave drying, thin layer drying models, effective diffusivity