Supercritical extraction technique of agarwood essential oil induced by plant hormones

Samples of agilawood (agarwood), which were studied in this work, were produced in Zhongshan City, Guangdong Province, China. To enhance incense production, a specific concentration of plant hormone is employed for induction. The extraction technology of agilawood essential oil was explored using supercritical carbon dioxide fluid, which exhibited a more pronounced induction effect. The pressure, temperature, and flow rate, respectively, were 8, 16, and 24 MPa; 35, 45, and 55 °C; and 20, 30, and 40 L/h. A Box-Behnken analysis was adopted for experimental data, which involved 33 experiments. The data were fitted with the equation Y = 2.18 + 0.1312X1 – 0.025X2 + 0.1236X3 – 0.0025X1X2 – 0.0125X2X3 + 0.0175X12 + 0.035X22 – 0.1275X32. Hence, the optimal process parameters in the supercritical extraction of agarwood essential oil were as follows: the pressure, temperature, and flow rate of 24 MPa, 35 °C, and 33 L/h, respectively. An analysis was conducted with the statistical analysis software Design-Expert 11, which indicated that the extraction yield of agarwood essential oil by supercritical carbon dioxide was mainly affected by the pressure and flow rate. The yield was proportional to the pressure and flow, and inversely proportional to the temperature.