Drying characteristics of walnut [Juglans regia L.] during convection drying

Abstract

A b s t r a c t. Drying characteristics of walnut were determined experimentally as a function of temperature, air velocity and variety (Serr, Pedro, Z67, K82). Four different drying models were fitted to the experimental data to select a suitable mathematical form of the drying curve. Experiments were performed at air temperatures of 32 and 43°C and two air velocities of 1 and 3 m s -1 at each temperature. Of the drying models tested, the Page model was selected as the best mathematical model based on the values of R 2 , c 2 and RMSE. Drying time and Page model constants were significantly dependent on the variables studied. Correlations of the Page model constant, k and m, the effective moisture diffusivity of walnuts and the drying time with the variables were determined. The effective moisture diffusivity of walnuts varied from 3.54×10 -7 to 9.92×10 -7 m 2 s -1 .