Understanding the phenomena of extraction of essential oils by the microwave accelerated distillation process: case of the Washington Navel variety

In this study, two techniques Hydrodistillation (HD) and Microwave-accelerated distillation (MAD), was used to extract essential oils (EOs), from the peels of citrus fruits Washington Navel (Citrus sinensis L. Osbeck) collected from Tipaza province, north Algeria during April 2018. The extraction yield and time of EOs were (0.28% and 180 min) using HD extraction and (0.27% versus 30 min) using MAD extraction. After using gas chromatography analyses (GC-FID) and (GC-MS), 21 aromatic compounds obtained and identified for both extraction approaches. On the other hand, and in order to better comprehension the extraction phenomena, two models of extraction processes were applied, The first one considers the existence of a single site with a constant speed ruled by the equation of the quasi-stationary state, whereas, the second assumes that there are two distinct sites: The first is part of the fraction easily accessible with a very high desorption rate k1 (fast fraction), the second contains the fraction that is difficult to extract, with a low desorption speed k2 (slow fraction). The results showed that, the application of the two sites model can describe accurately the used extraction methods in this study. The data from HD extraction modeling indicate that this method extraction is fast fraction (f equal 0.79), then MAD method (f equal 0.40). DOI: http://dx.doi.org/10.5281/zenodo.3881852