Application of high-power ultrasound for drying vegetables

Abstract

High power ultrasound represents a means for food dehydration without affecting the main characteristics and quality of the product. The application of ultrasonic energy can be made alone or in combination with other kind of energies such as hot-air. In this latter case ultrasound helps in reducing temperature or treatment time.

This paper deals with an experimental work in which the results obtained with different kind of vegetables (apple, carrots, mushroom, etc.) under the application of ultrasonic vibration at 20 kHz are presented. Several experimental techniques such us direct contact of the ultrasonic vibration with the product, standing wave and near-field conditions were tested, together with hot-air at several temperatures.