Optimization of supercritical CO2 extraction of oleoresin from black pepper (Piper nigrum L.) and antioxidant capacity of the oleoresin

Supercritical fluid extraction (SCFE) of oleoresin from ground black pepper (Piper nigrum L.) with carbon dioxide was studied. The aim of this study was to investigate the effect of different operating factors on the extraction yield and the piperine content in the extracts as well as to evaluate the antioxidant capacity of the extract. A Response Surface Methodology (RSM) with a 3-factor Central Composite Orthogonal Design (CCOD) was used to determine the effects of pressure (200-300 bar), temperature (35-55oC), and extraction duration (90-150 min) on the extraction yield. The results indicated that a quadratic model adequately represented the experimental data. The optimum parameters for the extraction of oleoresin obtained by RSM included 266 bar pressure, 47°C temperature and 150 min time, with the predicted extraction yield of 5.33%. The piperine content in the extracted oleoresin varied from 25.74% to 48.32%. Meanwhile, the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging capacity of the extract was a bit lower than that of ascorbic acid, showing 86.6% of inhibition at a concentration of 80 mg/L.