Separation of selected bioactive compounds from orange peel using the sequence of supercritical CO2 extraction and ultrasound solvent extraction: optimization of limonene and hesperidin content

The orange peel (Citrus sinensis L.) from the variety Washington Navel was extracted by supercritical CO2 (SC-CO2) at different parameters. The extracts were analyzed by gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). Limonene predominance was found (up to 89%). The principal oxygenated monoterpenes were linalool, alpha-terpineol, decanal, and (E)-citral. Ultrasound-assisted extraction was performed on the remaining solid residue (after SC-CO(2)extraction) to obtain the extracts rich in hesperidin. The influence of different extraction parameters on hesperidin content (3.3-23.0 mu g/mL) was determined. The prediction performance in optimizing the extraction yield of dominant compounds was studied by response surface methodology and artificial neural network.