Mathematical modeling of sun and solar drying of chilli pepper

The drying characteristics for chilli pepper using sun and solar drying were investigated. Chilli pepper was pretreated by water and steam blanching and by soaking in osmotic solutions of 60 and 70° brix. Untreated chilli pepper was taken as a control. The pretreated chilli pepper dried faster than untreated chilli pepper while the drying of both samples occurred in falling rate period. Four thin-layer drying models (Newton, Henderson and Pabis, Logarithmic and Page) were fitted to the experimental data to select a suitable drying equation. The Page model was found to best describe the drying behavior of chilli pepper for sun and solar drying.

► Limitations of sun drying led to need for alternative drying methods which include solar drying.
► Low fuel cost of solar drying makes it a better alternative drying method than hot-air drying.
► Pretreatment during drying is beneficial due to reduced drying time and nutrients depletion.
►  Study of sun and solar drying characteristics will help select suitable drying conditions for chilli.
► Selection of model best describing drying processes will make optimization of processes possible.