Abstract:

This work was conceived to optimize the extraction of essential oil from fresh vetiver roots by supercritical carbon
dioxide fluid extraction (SCFE-CO2). Firstly, one-factor-at-a-time (OFAT) method was employed to examine the effects of
particle size of powdered vetiver roots, volume charge coefficient, extraction pressure, extraction temperature, CO2 flow rate
and extraction time on the yield of vetiver oil. Subsequently, three key factors including extraction temperature, extraction
pressure and CO2 flow rate were optimized by response surface methodology (RSM) based on Box-Behnken design using
oil yield as the response variable. The results indicated that the optimum conditions that provided the highest extraction
yield were determined as follows: raw material granularity, 60–80 mesh; volume charge coefficient, 0.8; extraction pressure,
22.61 MPa; extraction temperature, 35.41 ℃; CO2 flow rate, 1.65 L/min; and extraction time, 1.5 h. Under these conditions,
the predicted maximum yield of vetiver oil was 7.780%, agreeing with the experimental value (7.762%). The chemical
composition of the extracted essential oil was analyzed by GC-MS. A total of 18 compounds which accounted for 69.88% of
the total extract were identified including 8-cedren-13-ol, dehydro-aromadendrene, myrcenone, vetiverol and vetiverone as
the main components. The applications of these components in various fields were summarized in this work.

Key words: supercritical CO2 extraction, vetiver essential oil, response surface methodology, gas chromatography-mass spectroscopy (GC-MS)