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%).