Microwave-Assisted Plant Extraction Processes
Microwaves, as oscillating electromagnetic fields, are the perfect choice for rapid heating of dipolar molecules like water, and are thus of special interest in extraction processes for plant matrices. Volumetric microwave heating, in combination with solvent effects, can alter or damage cell structures, improving the extraction of compounds of interest. As a result, the enhanced extraction kinetics lead to more efficient processes, use less chemicals, have shorter extraction times, and provide higher extraction yields. This chapter aims to review the basic theory of microwave processing, providing useful information on the interaction between the plant matrix and the electromagnetic field, and the available bench-, pilot-, and industrial-scale applications. In addition, different microwave-assisted extraction strategies are outlined, together with a detailed description of the main process variables.