Ultrasonic-assisted extraction of antioxidative compounds from Bene (Pistacia atlantica subsp. mutica) hull using various solvents of different physicochemical properties

Extraction yield, phenolics content, and antioxidant activities of the materials extracted conventionally and/or ultrasonically from Bene hull by a number of aqueous and organic solvents were investigated. Higher extraction yields in general were obtained by the less polar solvents (12.1-47.5%). Polar protic solvents exhibited the highest content of total phenolics extracted (110-150 mg/g), followed by polar aprotic (30.0-43.5 mg/g) and non-polar solvents (3.3-5.2 mg/g). Good correlation (R2 = 0.9721) was obtained between the DPPH radical-scavenging activities and total phenolics contents. Many similarities were observed between the results of the DPPH (EC50 = 0.6-1105.3 μg/ml) and FRAP (0.1-8.5 mmol/g) assays. The highest oxidative stability index (OSI) value belonged to the methanol and water extracts, respectively. All the extraction factors significantly improved by 30 min sonication, especially in polar protic solvents. A 10-min sonication in water extraction could provide the same achievements as those of the 24-h conventional method.