4 - Ultrasound to improve drying processes and prevent thermolabile nutrients degradation

Abstract

Ultrasound is one of the most often investigated nonconventional technologies applied to enhance drying progress. The existing literature proves that ultrasound can be used to accelerate the process, reducing drying time and decreasing energy consumption. Shorter exposure to elevated temperature during water removal provides a better quality of product, expressed as both physical and chemical properties. Moreover, ultrasound treatment itself can participate in the modification of some quality parameters, due to the mechanisms that it provokes during pretreatment. On the other hand, the complexity of the phenomena and processes that can be induced in the food matrix by sonication is one of the biggest challenges for food scientists and engineers. Based on the results presented and discussed in this chapter, it seems that ultrasound application, when it aims towards drying improvement, requires optimization not only for each individual raw material but also for each specific process. This situation can be considered as a drawback and benefit alike since it opens multiple ways of ultrasound utilization for water removal enhancement.