A Study on Drying of Thin-Layer Pepino by Infrared and Microwave Methods and Their Color Analysis

Pepino is an exotic fruit that contains high vitamin C and is known to have many beneficial effects on health. In this study, thin layer drying and color changes of pepino fruit by infrared (IR) and microwave (MW) methods were investigated. Effective moisture diffusions and activation energy were calculated from the drying data. Uniformly sliced pepino fruit was processed without peeling. While IR drying processes were performed at 60, 70, and 80 °C temperatures in 210, 165, and 120 minutes, respectively, MW drying processes were completed at 25, 16, and 6 minutes at 140, 210, and 350 W power levels. While the initial average moisture content was 18.5702 kg water/kg dry, the lowest moisture content was determined as 0.3250 at 80 °C in IR and 0.1263 water/kg dry matter×min at 350 W at MW. Effective moisture diffusions (Deff) for IR were calculated between 6.69 × 10-10 - 1.23 × 10-9 m2/s, while for MW it was found between 8.75 × 10-9 - 3.75 × 10-8 m2/s. The activation energy (Ea) was 29.80 kJ/mol for IR and 33.30 kW/kg for MW. In addition, it was determined that color preservation was better in the IR method, and local burns were observed in the samples in the microwave method.