COMPARISON OF THE EFFICIENCY OF DIFFERENT EXTRACTION METHODS ON ANTIOXIDANTS OF MALTEASE ORANGE PEEL

The effect of conventional solvent extraction, CSE, ultrasound assisted extraction, UAE, microwave assisted extraction, MAE and supercritical CO2 extraction, SC-CO2 on the total phenols content, total flavonoids, individual flavonoids and antioxidant activity of orange peel were compared. Neohesperidin (from 0.624 ± 0.013 for SC-CO2 extraction to 1.045 ± 0.001 g100 g orange peel powder for MAE) and hesperidin (from 0.407 ± 0.008 for SC-CO2 extraction to 0.836 ± 0.029 g/100 g orange peel powder for UAE) are the major flavonoids (80% of total flavonoids by MAE and 87% by CSE) of orange peel whatever the used extraction method. The method giving the highest total phenol and flavonoid contents is microwave assisted extraction (2.363 ± 0.014 g GAE/100g orange peel powder), followed by ultrasound assisted extraction, conventional solvent extraction, and supercritical CO2 extraction. However, antioxidant activity (DPPH method) cannot be correlated to TPC, TFC or individual flavonoids. Orange peel extracted by CSE (ethanol (80%), m/v: 5 g: 50 ml, 30 min, 35°C, mechanical stirring at darkness, 3 successive extractions) presents the higher radical scavenging capacity compared to the other extracts obtained by MAE (Ethanol (80%), m/v: 5 g: 50 ml, 10s, 35°C, 170 W, 3 successive extractions) and UAE (ethanol (80%), m/v: 5g: 50 ml, 30 min, 35°C, magnetic stirring at darkness, 3 successive extractions, 125 W), SC-CO2 extraction (ethanol (80%), m/v:5 g: 50 ml, 30 min, 35°C, 22 MPa, 3 successive extractions). Besides, no additivity on the antioxidant activity is found with the DPPH method.