ABSTRACT
In this chapter, the basics of osmotic dehydration (OD) including the mechanism of the process, the parameters affecting the process, its effect on the main quality and nutritional properties, as well as its common applications are presented. Empirical, semi-empirical, mechanistic, and phenomenological approaches (e.g., Crank’s model) describing mass transfer phenomena are overviewed and an illustrative example of the methodology applied for osmotic dehydration calculations is provided. Emphasis is given on novel approaches concerning the use of osmotic dehydration, including the incorporation of alternative osmotic agents (sorbitol, maltitol, glycerol, maltodextrin, trehalose, fructooligosaccharides, etc.), the introduction of hybrid techniques in order to optimize OD effect (vacuum impregnation, pulsed electric fields, ultrasound, γ-irradiation, high pressure, etc.), the incorporation of valuable compounds by coatings and emulsions, and especially the combination of OD with encapsulation procedures. The most important advantage of this combined process is its versatility that allows for designing tailor made, healthy food products with desired flavors and functional substances. Although the osmotic dehydration as an impregnation/incorporation method has been widely studied, the application of this mild thermal treatment as an encapsulation method is newly introduced, but seems rather promising and warrants further investigation.
