Quality comparison of camellia (Camellia oleifera C. Abel) seed oil with different extraction methods

The quality of camellia seed oil (CSO) varies with the oil extraction methods. In the present work, the oil yield, physicochemical properties, bioactive compounds, fatty acid composition, and Fourier transform infrared spectra of CSOs prepared by supercritical fluid, aqueous, pressing, and solvent extraction were explored systematically. Additionally, the microstructure of camellia seed cake after oil extraction was observed by scanning electron microscopy. Results showed that supercritical fluid extraction had the highest oil yield (92.42%), and the extracted oil was also superior to the other methods in the contents of polyphenol, β-sitosterol, and squalene, which were 89.34, 3173.23, and 6.20 mg/kg, respectively. Moreover, CSO extracted by supercritical fluid extraction had lower peroxide value and better colour indexes. In terms of fatty acid composition, CSOs extracted by supercritical fluid, pressing, and solvent extraction were similar, while CSO extracted by aqueous extraction had higher saturated fatty acid contents and lower unsaturated fatty acid contents than the other samples. Fourier transform infrared spectra analysis showed that the extraction methods had no significant effect on the chemical functional groups of CSOs. Scanning electron microscopy revealed that supercritical fluid extraction and solvent extraction could more effectively promote the release of oil from camellia seeds. In general, the quality of CSOs extracted by different methods had significant differences, and supercritical fluid extraction could be a promising extraction method for CSO.