Study on the Process for Extraction of Onion Oil by Supercritical CO_2

Experiment on extraction of onion oil with supercritical CO2 was carried out. The influences of operating pressure, operating temperature, entrainer and extracting time on the yields of onion oil were studied. Through orthogonal experiments, the best parameter of extraction of onion oil with SC-CO2 extraction technology was ascertained. It was found that the order of the influences factors on the yields of onion oil is Extracting pressure Entrainer Extracting temperature Extracting time. The optimal parameters were that extracting pressure, 20 MPa; entrainer, 15 % anhydrous ethanol, extracting temperature, 40 ℃; extracting time, 240 min. At this condition, the yield of onion oil could be 0.492 %.