Heat efficiency improvement and color evaluation of red chili pepper (Capsicum frutescens) drying with air dehumidification using silica gel

Abstract

Fresh red chili pepper (Capsicum frutescens) can be dried to a moisture content below 15% for prolonged storage life for a wider range of applications such as in the medicinal, food, and chemical industries. Currently, red chili pepper drying is conducted with direct solar heat that is very dependent on weather conditions. Meanwhile, common convective drying with fossil fuel is inefficient in heat usage and operated at high-temperature air which could potentially lower the product quality. Convective drying with air dehumidification works at low-medium temperatures that are conducive for red chili pepper drying. This research aimed to determine the effect of dehumidification with silica gel on heat efficiency and its impact on the red chili pepper’s quality of color. Drying was conducted at temperatures in the range of 40-70℃ with silica gel as an air dehumidifier. The moisture content and colour of red chili pepper were observed. Results showed that red chili drying with silica gel at a temperature below 60°C can improve the heat efficiency as well as the red chili color retention.