Investigation of Drying Characteristics of Pepper Using Solar Dryers in Ondo State

This study investigates the drying characteristics and quality outcomes of pepper dried using an indirect solar dryer compared with open sun drying in Ondo State, South West Nigeria. Pepper is a commercially important spice crop in Nigeria, and drying is the primary preservation and marketing preparation operation. Traditionally, farmers sun-dry pepper on bare ground or mats, resulting in contamination, uneven drying, and significant quality losses from mould and dust. This study fabricates an indirect solar dryer with a flat-plate collector, drying chamber, and natural convection airflow system using locally available materials. Drying experiments are conducted using ripe red pepper at an initial moisture content of 78 percent wet basis. Drying rates, final moisture content, colour retention, capsaicin content, and microbial load are compared between solar dryer and open sun drying treatments over five replicate drying runs at Ondo State University of Science and Technology. Findings reveal that the solar dryer reduces drying time by 32 percent compared to open sun drying and achieves final moisture content of 10.2 percent within an acceptable range. Solar-dried pepper shows significantly higher capsaicin content, better colour retention, and lower total bacterial count compared to open sun-dried samples. The study concludes that indirect solar drying significantly improves pepper quality while reducing drying duration. It recommends a community solar dryer demonstration programme for pepper farming communities in Ondo State.

Keywords: solar dryer, pepper drying, post-harvest quality, Ondo State, food preservation.