**5. Discussion and work perspectives**

The performed analysis describes the thermo-acoustic behavior of ultrasound waves and food samples in an ultrasound-assisted convection dehydration system considering two case studies. In the first one, we use separately apple and tomato samples placed in five gridded trays spaced 3 cm from each other and ultrasound– radiated inside the dehydration chamber by using one piezoelectric transducer. In the second case study, we use the same conditions of the spatial distribution of food samples but using three piezoelectric transducers. From the thermo-acoustic analysis, the optimal operating frequencies were identified for apple (around 34 kHz) and tomato (around 70 kHz) samples. Also, from a temperature control on food samples,

### *Acoustic and Thermal Analysis of Food DOI: http://dx.doi.org/10.5772/intechopen.108007*

we identified the operating pressures that avoid the structural and nutritional damage of the food samples under consideration in the dehydration process. By obtaining the acoustic and thermal behavior of apple and tomato samples in an ultrasound-assisted convection dehydration system, we can design an ultrasound-assisted dehydration system that improves the quality, time, cost, and energy of small– and large-scale dehydration processes. The development of new technologies focused on ultrasoundassisted convection dehydrator systems for food dehydration remains a challenge for the scientific community when considering acoustic, thermal, mechanical, and biochemical approaches in the design, purchase, or implementation of dehydration systems applied to human consumption foods. Moreover, from these new technologies, it is possible to obtain dehydrated products with high nutritional content and little structural damage that, without leaving behind a good taste and texture, may allow the human being to store food and its subsequent consumption in a long-term time. Finally, it is necessary to emphasize that although there are several commercially available ultrasound–assisted dehydration systems, there is still a gap to be filled so that ultrasound-assisted systems can be applied in multiple food fields at an industrial level, and at the same time, that these systems tend to be used on a daily basis at affordable prices in households around the world.
