Response surface methodology applied to supercritical carbon dioxide extraction of Piper nigrum L. essential oil

- We obtained Piper nigrum L. essential oil using SC-CO2 extraction method.
- We applied central composite design of the RSM to optimize the SC-CO2 extraction.
- RSM was able to optimize the SC-CO2 extraction of P. nigrum L. essential oil.
- Pressure was the most effective factor in the variation of the extraction's yield.

This study was conducted to optimize the supercritical carbon dioxide (SC-CO2) extraction of Piper nigrum L. essential oil using response surface methodology (RSM). In order to obtain the maximum yield of the essential oil, experiments were carried out using a three-factor central composite design (CCD) under following conditions: pressure of 15-30 MPa, temperature of 40-50 °C and dynamic extraction time of 40-80 min. A second-order polynomial regression model expressing the total extraction yield as a function of main SC-CO2 variables was significantly (p < 0.05) fitted, with high coefficient of determination value (R2 > 0.985). The results showed that the best extraction yield (2.16%) was obtained at 30 MPa, 50 °C and 80 min. Pressure showed the most significant (p < 0.05) effect on the yield variation. The chemical composition of the essential oil was determined using GC-flame ionization detection (FID) and gas chromatography-mass spectrometry (GC-MS) analysis. The main constituents (concentration > 3.0%, calculated as % peak area) in the P. nigrum L. essential oil obtained through SC-CO2 extraction were determined to be β-caryophyllene (24.34%), limonene (15.84%), sabinene (15.04%), 3-carene (9.44%), β-pinene (9.27%) and copaene (4.52%).