Ultrasonic-Assisted Convective Drying of Apple Slices

A promising approach for the application of ultrasound to assist in convective food drying was developed and tested in this study. The application of ultrasound is based on the transmission of ultrasonic energy as a combination of airborne contacts and through a series of solid contacts between the ultrasound element and the product tray as the ultrasonic vibration transmitting surface. A computer-based ultrasonic drying setup was built to allow continuous recording of the process variables in real time and enabled simulation of dehydration to be accomplished under controlled conditions over a range of drying parameters. Apple slices were dried using the drying setup to study the influence of ultrasound in combination with conventional hot air drying on drying kinetics and product quality. The results from this work indicate that ultrasound can simultaneously be applied to accelerate the processing time (i.e., reduce energy consumption and increase production throughput) in conventional hot air drying wit...