Drying kinetics, moisture diffusivity and lycopene retention of watermelon pomace in different dryers

Abstract

Drying kinetics of watermelon pomace was investigated in fluidized-bed and cabinet dryers using 2–6 kg/m2 tray loads at 50–70 °C. Drying behavior was described by the Page’s model with high coefficient of determination (≥0.96), lower standard error (≤0.03) and scattered residual plot. Effective moisture diffusivity of pomace during drying varied from 0.880 × 10−8 to 3.541 × 10−8 m2/s for fluidized bed and 0.347 × 10−8 to 0.868 × 10−8 m2/s for cabinet dryers. Arrhenius’s equation adequately explained the relationship between the drying rate constant/effective moisture diffusivity and drying air temperature. Lycopene content of dehydrated watermelon pomace was 11.0–17.3 mg/100 g dry basis in fluidized-bed dryer and 9.3–15.4 mg/100 g dry basis in cabinet dryer.