Experimental investigation of drying kinetics of apple with hot air, microwave and ultrasonic power

The experiments were performed for various conditions at 40–60 °C air temperature, 0.5–1.5 m/s air velocity, 120–600 W microwave and 50–200 W ultrasonic power so as to investigate the effects of drying air temperature, air velocity, microwave and ultrasonic power on the drying characteristics of apple slices. In the study, the combined use of hot air, microwave and ultrasonic energy for apple slices was determined as the most effective and fastest drying method. Besides, according to the experimental results applied to the models selected from the literature, the model that best described the drying characteristics of the apple under the microwave and ultrasonic effect was that of Midilli et al and the correlation coefficient R2 was calculated to be between 0.9969 and 0.9999.