Supercritical CO2 extraction of fatty oil from flaxseed and comparison with screw press expression and solvent extraction processes

Flax oil is commonly used in food due to high percentage of omega-3-fatty acid and omega-6-fatty acid. In the present work the flax seed was extracted using green solvent viz. supercritical CO2 and compared with soxhlet and mechanical screw press methods. The chemical compositions of the oils were determined by CHNS analyser, GC-FID, GC/MS and 1H NMR. The supercritical CO2 process selectively extracted the fatty oils with high percentage of omega-3-fatty acid and omega-6-fatty acids. The chemical composition of screw press oil is close to that of supercritical CO2 extracted oil, whereas the yield is nearly 27% less in comparison to the supercritical CO2 method.