New Food Drying Technologies - Use of Ultrasound
A. Mulet, Juan A. Cárcel, Neus Sanjuán, J. Bon
Food Science and Technology International
Abstract
Reducing water availability is one way to preserve food. Water in solid foods is transferred to a fluid, either gas or liquid; during this process both internal and external resistance affect water transfer from the food. As a consequence, any means to reduce those resistances constitute an improvement of the process, and ultrasound appears to be a way to reduce those resistances. Ultrasound are mechanical waves that produce different effects when travelling through a medium. Among others, those related to mass transfer include micro-stirring at the interface, the so called “sponge effect” and cavitations. Ultrasound has so far been applied to dehydration in solid-gas systems like onion drying. Nevertheless, the difficulties for the propagation in the air have led to the development of specially adapted transducers that have been applied in the drying of carrots. In solid-liquid systems, ultrasound has been used in the treatment of products immersed in hypertonic solutions, either in sugar solutions for fruits like apples or in salt brine in the case of cheese or meat. An increase in mass transfer is achieved if the threshold power value for the product is attained.
Extracted Claims
6 claims extracted from this paper into the knowledge graph
ultrasound applied to carrot drying with specially adapted transducers
“Nevertheless, the difficulties for the propagation in the air have led to the development of specially adapted transducers that have been applied in the drying of carrots.”
ultrasound applied to onion drying in solid-gas systems
“Ultrasound has so far been applied to dehydration in solid-gas systems like onion drying.”
ultrasound produces micro-stirring, sponge effect, and cavitations
“Among others, those related to mass transfer include micro-stirring at the interface, the so called “sponge effect” and cavitations.”