Microwave Processing: Impact on Food Product Quality Attributes

Microwave (MW) heating belongs to the so-called new, innovative, or emerging thermal processing technologies that have been developed or are still under investigation with the main aim of overcoming some typical problems associated with conventional thermal technologies. These problems include cost and environmental aspects, but first of all, the thermal impact on food quality, particularly in terms of loss of nutritional quality. In fact, irrespective of the main purpose of the heating process (preservation, development of taste and flavor, changes in structure to obtain a specific texture), a certain level of thermal damage will occur. Food technologists and engineers have been working in the direction of minimizing such thermal impact following a concept of total food quality, which cannot consider only the safety aspect (which is, indeed, a prerequisite that needs to be guaranteed for any food product) but also the nutritional and sensorial quality of the final product. This chapter provides an overview of the basic mechanisms of MW heating, with a focus on its possible applications in the food sector (pasteurization and sterilization, baking and cooking, heating and tempering, drying and extraction), underlining, for each application, the main limits of conventional thermal technologies and the potential advantages of MW treatment, together with its drawbacks. The impact of MW application on the different food properties (safety, sensorial, and nutritional) will be addressed, such as the actual industrial implementation of this technology.