Antioxidative Activity of Olive Pomace Polyphenols Obtained by Ultrasound Assisted Extraction

This study was carried outto investigate the effect of ultrasound-assisted extraction (UAE) on polyphenols from olive pomace with methanol (80%) as an extracting medium and studythe effects of addingthe extract to refined sunflower oilduring accelerated oxidationconditions. Ahigh amount of polyphenols was extracted from the olive pomace with a solvent-to-solid ratio of 40 at 50% of the maximum output power for 30 min.Polyphenols of the extractswere identified and quantified by high-performance liquid chromatography.Sonicated extracts were characterizedby the presence of pyrogallol, 3-hydroxytyrosol andoleuropein.The most common flavonoids in the extracts were hesperidin, naringin, and hesperetin. The antioxidant activity of olive pomace extract was evaluated and compared to butylated hydroxytoluene (BHT) using the Rancimat assay. Olive pomace extract at 150 mg Gallic Acid Equivalents/kg oil was superior in protecting sunflower oil against oxidative deteriorative changes than BHT at 200 ppm.