Primary study on solvent-free microwave extraction of essential oil from Citrus grandis peel

The essential oil was obtained by solvent-free microwave extraction through a self-designed microwave hydrodiffusion and gravity installation from pomelo (Citrus grandis Osbeck) peel. The yield, physical properties and gas chromatography of the essential oil was compared with that of the traditional hydrodistillation. It could be concluded from the results that 250 g peel could extract about 0.40 mL essential oil by both extraction methods, and the quality and ingredients of the essential oil extracted by solvent-free microwave extraction were similar to those of hydrodistillation. Furthermore, the solvent-free microwave extraction could save around 90% time and 60% energy.