Effect of different operating conditions on the extraction of phenolic compounds in orange peel

• Extraction of phenolic compounds from orange peel.
• Effect of power for ultrasound and microwave extraction.
• Effect of pressure of high pressure extraction.
• Effect of temperature and pressure for the extraction supercritical CO2.
• Low powers are recommended for UAE and MAE; antioxidant activity is higher with HPE.

The effects of different operating conditions on four extraction techniques were studied and compared. The criteria analyzed were total phenol and flavonoid contents, individual flavonoids and antioxidant activity. The common operating conditions of extraction are ratio m/v: 5 g:50 ml; 80% ethanol with mechanical agitation. It appears that the highest values for the total phenol and flavonoid contents were reached when ultrasound assisted extraction (UAE) was carried out at 125 W during 30 min at 35 °C, microwave assisted extraction (MAE) at 200 W during 180 s, supercritical CO2 extraction (SCE) at 80 °C, 10 MPa and high pressure extraction at 50 MPa during 30 min at 35 °C. These conditions are not optimum to obtain the highest antioxidant activity for MAE (300 W) and HPE (100 MPa).