Drying kinetics of chillies in deep-bed dryer

Drying characteristics of red chilli in different layers of deep-bed dryer (DBD) at 55 degrees C were studied. It took 20, 21 and 23 h to dry chilli in bottom, middle and top layers (5 cm thick each) of DBD, respectively from its initial moisture content of around 310% d.b. to the final moisture content of around 10.5% d.b. at 55 degrees C of drying air temperature. The average capsaicin content and red colour value (a*) of dried chilli increased from 0.47 to 0.57% and 18.7 to 23.3, respectively as the drying front of chilli moved from bottom to top layer of DBD. The Kaleemullah and Page models can be used to predict the moisture ratio of chilli at different layers of DBD. The effective moisture diffusivity (D-eff) of chilli decreased from 1.8286x10(-5) to 1.5231x10(-5) m(2)/h as the drying front moved from bottom to top layer.