ABSTRACT
Plant-based food materials are complex in nature as they have heterogeneous, amorphous, hygroscopic, and porous properties. During drying, the microstructure of food materials changes, which significantly affects its other properties. An appropriate understanding of the microstructure of the raw food material and its evolution during drying is critical to understanding and accurately describing drying processes and anticipating food quality. Heat and mass transfer causes the modification of microstructure in the course of drying of fruits and vegetables. Introduction of an additional heat source, such as microwave and infrared, in intermittent drying results in further modification of the microstructure. Changes in microstructure affect functional properties of dried food materials. In this chapter, the effect of the intermittent application of secondary heating, such as microwave or infrared, along with the convective heating, is discussed. In addition to this, an attempt to correlate the intermittency of microwave heating, microstructural modification, and dried food quality has been made. Therefore, this chapter would provide an enhanced understanding of the relationships between food microstructure, drying process parameters, and final product quality, which in turn facilitate the development of energy-efficient optimum drying process to achieve high-quality dried food.
