Abstract: This study was to investigate the optimum extraction conditions of essential oil from jasmine flower buds and antioxidation of the extraction by supercritical CO₂ extraction,and the comprehensive utilization of jasmine flower bud resources was realized.Firstly,the effects of entrainer dosage,raw material particle size,extraction pressure,extraction temperature and dynamic extraction time on the extraction yields of jasmine essential oil were investigated by single-factor experiment combined with central combination design method of Box-Behnken.The compositions and relative contents of volatile oil were analyzed by GC-MS (Gas Chromatography-Mass Spectrometer).Finally,the ability of essential oil to scavenge DPPH free radicals and reduce iron ions were evaluated.The results showed that the optimum extraction parameters were as follows:entrainer ethanol dosage 0.2 mL/g,particle size 40 mesh,extraction pressure 20 MPa,extraction temperature 46 ℃,dynamic extraction time 1.6 h.Under this condition,the yield of jasmine essential oil was 13.67%,which was much higher than SDE (simultaneous distillation extraction) (2.87%) and UAE (ultrasonic assisted extraction) (2.45%).The main compositions of aroma of essential oil extracted by supercritical carbon dioxide extraction were basically as the same with jasmine flowers.According to the antioxidant activity experiment,the essential oil has good ability to scavenge free radicals and reduce iron ions.The experiment has proved that the extraction of jasmine buds by supercritical extraction technology can get high quality of jasmine essential oil,which can provide a reference for its comprehensive utilization of resources.

Key words: supercritical CO₂ extraction, essential oil, jasmine flower buds, response surface optimization, antioxidant activity