Single Layer Drying Behavior of Apple Slices in a Microwave Dryer

Abstract

In this study, the drying behaviour of single layer apple slices of 5mm thickness in a microwave dryer was investigated experimentally for four different microwave power levels (90 W, 180 W, 360 W and 600 W) and suitability of drying models available in the literature in simulating the drying behaviour of apple slices was determined by statistical analysis. The performance of these models was determined by comparing the coefficients of determination (R), reduced chi-squares (χ2) and root mean square errors (RMSE) of the models. The results show that drying time and energy consumption decreases considerably with increasing microwave power. The results also show that, among of the models proposed, the Verma et al. model gives the best fit with experimental data for all drying conditions considered. In order to determine the colour change of apple, a colour meter was also used in this study and found that L* and a* values were not significantly different from the values of the fresh apples.