Drying characteristics and modeling of tomato thin layer drying in combined infrared-hot air dryer

In this study tomato slices were dried with three thicknesses (3, 5 and 7 mm), three temperatures (60°C, 70°Cand 80°C) and air speed of 1.1 ms-1 in a combined infrared-hot air dryer. Distance from infrared source was 70 cm, while, input air temperature was 60°C. The experiment was conducted as factorial based on a completely randomized design. Results showed that energy consumption reduced along with the increase in temperature and slice thickness. Decrease in the slice thickness from 7 to 3 mm resulted in a significant decrease in drying time. Maximum diffusion coefficient was related to the thickness of 7 mm and the temperature of 80°C, while, the minimum value was related to the thickness of 3 mm and the temperature of 60°C. Effective diffusion coefficient and activation energy is, respectively, 9-10 m2 s-1 to 10-11 m2 s-1 and 12.7-110 kJ mol-1. Middili's model had the maximum R2 and the minimum RMSE and SSE at different temperatures and speeds, thus, it was considered as the fittest model to predict the moisture