Antioxidant activity of phenolic fractions in olive mill wastewater

► Five OMW fractions were obtained and their antioxidant potential was determined. ► The main phenolic compounds in these fractions were hydroxytyrosol, and tyrosol. ► The fractions AAA and s-TP showed very high antioxidant activity. ► Antioxidant activity attributed to total phenol content and hydroxytyrosol level.