Compositional and Antioxidant Activity Analysis of Zanthoxylum bungeanum Seed Oil Obtained by Supercritical CO2 Fluid Extraction

Supercritical CO₂ fluid extraction (SFE-CO₂) of Zanthoxylum bungeanum (Z. bungeanum) seed oil was investigated. To optimize the SFE process, three-level Box-Behnken factorial design and response surface methodology (RSM) were applied to optimize the extraction conditions, including pressure, temperature and amount of modifier. The optimum conditions were as follows: extraction pressure, 29.28 MPa; extraction temperature, 41.19 °C; and the added amount of modifier, 10.94%. The experimental results showed that the maximum extraction yield was 21.85 ± 0.23% (n = 3) under the proposed conditions. The compositional analysis of Z. bungeanum seed oil was performed by HPLC-FLD-MS using a new labeling reagent of 2-(11H-benzo[a]carbazol-11-yl)-ethyl-4-methyl benzenesulfonate (BCETS). The results indicated that the Z. bungeanum seed oil contained mainly unsaturated fatty acids, including C18:3, C22:6, C20:4, C18:2, C18:1 and C20:1, which accounted for 84.0% (mass percentage) of the total amount. The antioxidant activity of seed oil obtained by Box-Behnken design concerning the DPPH radical was investigated, and this indicated that the pressure and the amount of added modifier had positive effects on the antioxidant activity, but the effect of the temperature elevation is complicated, depending on the nature of the extracted contents.