Olive stones as source of antioxidants for food industry

The aim of this work was to produce a polar extract with antioxidant properties to be used in the food and cosmeticindustries, as functional foods and nutraceutical additives, starting from the olive stones, a by-product in the destonedExtra Virgin Olive Oil production. The multistep extraction procedure to produce the ethanolic extract of olive stonessignificantly increases the economic value of a cheap, renewable and potentially rich source of antioxidant compounds.The impact of extraction method and the efficiency of the solvent extraction were evaluated by running the same extractionprotocol using solvents with different polarity. For each solvent, the recovery yield and the total phenol compoundswere determined. The evaluation of the antioxidant activity of the alcoholic fraction was performed by measuring thetotal antioxidant activity and the scavenging properties against 2,2’-diphenyl-1-picrylhydrazyl radical, which show theefficiency of the polar extract in preventing the damages induced by free radicals, with low inhibitory concentrationIC30 (concentration required to reduce initial DPPH concentration by 30%) value (0.060 mg·ml-1). In addition, theconcentrations of total phenols and flavonoids in the extract were determined, showing that flavonoids represent aboutthe 60% of antioxidants with phenolic groups. Finally, the extract showed a relevant ability (IC30 of 1.30 mg·ml-1) topreserve -carotene from lipidic peroxidation.