Mathematical modeling of thin layer drying kinetics of apples slices

Abstract

This study presents a mathematical modeling of thin layer drying of apple slices in a forced convection dryer. In order to estimate and select the appropriate drying model, ten different models which are semi-theoretical and/or empirical were applied to the experimental data and compared. In this research, the rectangular (20×20×5 mm) apple slices sample were dried as single layer with thickness of 5 mm in the air temperature range of 45–60 °C and the air velocity of 0.75– 1.25 m/s in a hot air dryer. Then, the mathematical models were fitted to the experimental data. The models were compared with using the correlation coefficient and the root mean square error. According to the results, the Wang and Sing model was found to best explain thin layer drying behavior of the apple slices as compared to the other models over the experimental temperature and air velocity range. The effects of drying air temperature and velocity just above their surface on the constants and coefficients of the selected models were also studied by linear regression analysis.