Mathematical modelling of drying kinetics of red chilli as a function of loading density

Drying kinetics of red chilli (CH-27) under mechanical drying, sun drying and improved sun drying was studied for whole and chopped chillies at three loading densities of 2.5, 5.0 and 7.5 kg/m². Chopped chillies took less time to dry and attained lower equilibrium moisture content under all drying techniques and at all loading densities i.e. 5.21±0.51% and 13.43±1.87% for chopped chillies as compared to 7.1±0.75% and 18.61±2.35% for whole chillies for mechanical drying and sun and improved sun drying, respectively. It took 62, 50.75 and 28.25 hours for whole chillies and 30.58, 27.33 and 26.17 hours for chopped chillies to dry at 7.5, 5 and 2.5kg/m², respectively in mechanical drying which was much less as compared to sun and improved sun drying i.e. 54.83 sunshine hours (15 days) and 32.33 sunshine hours (9 days) for whole and chopped dried samples at all loading densities. Loading density had insignificant effect on final moisture content for all three drying methods. The Page Model was found to be the best fit to represent drying behaviour of chillies (R²>0.95 and SEE<0.37).