Abstract: This experiment studied the supercritical CO2 fluid extraction(SFE-CO2) technology of Carya kernel oil(CKO). The results showed the extraction rate was high when the grind degree was 0.9～0.4 mm(20～40 mesh), time longer than 2 h, pressure higher than 30 MPa and temperatures 35～45 ℃. On basis of single factor test, the orthogonal test was used in optimization of technological parameters. The feasible technological conditions were 2.5 h, 30 MPa, 0.6 mm(30 mesh)and 40 ℃. By the above conditions, the extraction rate could be 95.74%. The effects of extraction methods on CKO physicochemical properties were researched. Compared with the ether extraction and the aqueous extraction, the obtained oil by SFE-CO2 has the following several traits:the high iodine, the low acid value, the low sponification value and the low peroxide and so on. By means of gas chromatography (GC), 93.55% unsaturated fatty acid were determined in the oil, including oleic acid 68.01%, linoleic acid 23.21% and linolenic acid 2.11%.

Key words: Carya kernel oil, supercritical CO2, extraction technology, properties