Drying Characteristics of Red Chillies: Mathematical Modelling and Drying Experiments

The effects of drying conditions on the drying behaviour of Red Chillies (Capsicum annum) and the applicability of drying models to predict the drying curves of Red Chillies were studied. The experiments were conducted at different temperatures (90, 120, 140,160,180 and 200°C) with varying air velocities. Drying air temperature was found to be the main factor affecting the drying kinetics of Red Chillies; raising the drying temperature from 90°C to 200°C dramatically reduced the drying times. The effect of the relative humidity was lower than that of temperature; increasing the relative humidity resulted on longer drying times. Higher equilibrium moisture contents were obtained with high relative humidity’s and low temperatures. Furthermore, drying was observed only in the falling-rate period. Statistical analysis was carried out and comparison among drying models was made to select the best-fitted model for the drying curves.