Drying of Orange and Selection of a Suitable Thin Layer Drying Model



Orange (Citrus cinensis) is one of the most important among citrus fruits. The thin layer drying kinetics of orange (Thompson variety) slice was here experimentally investigated in a convective dryer and through mathematical modeling and by use of thin layer drying models. Drying characteristics of oranges were determined using heated ambient air at temperatures from 40 to 80 °C and velocities from 0.5 to 2.0 m/s. Beside the effects of drying air temperature and velocity, the effects of slice thickness on the drying characteristics, drying time were also determined. Drying curves obtained from the experimental data were then fitted to the thin layer drying models. The effects of drying air temperature and velocity on the model constants and coefficients were evaluated through a multiple regression technique. The models were compared according to three statistical parameters, i.e. root mean square error, chi-square and modeling efficiency. The results have shown that, increasing the drying air temperature and velocity causes shorter drying times. Midilli et al. model was found to be the most appropriate model for describing the drying curves of oranges. The effects of drying air temperature and velocity on the drying constant and coefficient were also investigated.