As can be seen in Fig. 3, the extraction process clearly
displays an exponential behavior with the presence of two phases.
The first phase that corresponds to a rapid increase in the yield,
which other authors have associated with an easy accessibility of solvent to the EO (Reverchon et al., 1999; Farhat et al., 2009), and a second phase, almost asymptotic, that defines the end of the process and it is limited by the mass transfer.
This kind of behavior in the extraction of EO from plants have been observed not only for microwave extraction,
it was found that the presence of the two phases is due to changes in the mass transfer mechanisms and the changes in the surface area from which essential oils evaporates