Prediction of the antioxidant activity of extra virgin olive oils produced in the Mediterranean area

•Estimating the antioxidant activity of EVOO by using a chemical index as a predictor has been evaluated.•K225 is effective for estimating the oil antioxidant activity, expressed with IC50.•The proposed method could be used for monitoring oil quality in terms of nutraceutical properties. A chemical characterisation was conducted on 75 commercial extra virgin olive oils (EVOO) produced in the years 2011–2012 in Southern Italy from five different olive monovarieties (Coratina, Leccino, Maiatica, Ogliarola del Vulture and Ogliarola del Bradano). The possibility of estimating the antioxidant activity of EVOO by using a chemical index as predictor of this property was considered. In order to build up and validate an antioxidant activity predictive model, the relationship between the antioxidant activity and the chosen chemical parameters was systematically investigated. The results indicated that oil antioxidant activity, measured as IC50, could be satisfactorily predicted, for olive oils from the considered region, by using a simple index, such as the K225 value of oil samples, which represents a spectrophotometric index of the compounds responsible for oil bitterness measured at 225nm.