Power ultrasound in food industry processing represents a novel tool, which is becoming increasingly appreciated. The use of ultrasonic energy is very promising because it can act without affecting the main characteristics and quality of the products. This work investigates the kinetics of ultrasonic dehydration processes of vegetables by direct contact vibrator-product. To that purpose, a parametric study of the relative influence of the main physical parameters involved in the process has been carried out. A specific experimental set-up has been designed, developed and tested. Trials were carried out with potatoes and apples. A 20kHz resonant transducer was designed with the aim to obtain high-amplitude displacements. Assessment of the properties of the samples (residuary moisture content and viscoelastic constants) is obtained from the analysis of high frequency (0.5-1MHz) wideband ultrasonic signals transmitted through the samples by using air-coupled transducers. The dehydration results show a notable influence of ultrasonic vibration on the kinetics of the process.
S. de la Fuente, E. Riera, J.A. Gallego-Juárez, T.E. Gómez, V.M. Acosta, F. Vázquez
World Congress on Ultrasonics WCU 2003 Proceedings, September 7-10 Paris, CD (ISBN 2-9521105-0-6), 61-64
