Abstract: The fatty acid composition of gardenia fruit oils extracted with supercritical CO2 under varying conditions of pressure, temperature and CO2 flow rate was determined by gas chromatography. The results showed that there were mainly 5 fatty acids in gardenia fruit oil, namely linoleic acid, oleic acid, palmitic acid, stearic acid and linolenic acid, of which the contents were respectively 44.38%, 24.96%, 24.83%, 2.55% and 1.31% in the oil extracted under 30 MPa, 55 ℃ and CO2 flow rate of 15 kg/h. Each of the three extraction conditions had some effect on the composition of fatty acids in gardenia fruit oil, which showed no statistical significance. It was found that gardenia fruit oil had the ability to scavenge DPPH and ABTS+ free radicals, indicating its antioxidant activity. Moreover, extraction pressure, temperature and CO2 flow rate could affect the DPPH and ABTS+ free radical scavenging activities of gardenia fruit oil to different extents.

Key words: gardenia oil, supercritical CO2, fatty acid composition, antioxidant activity