Antioxidant activity of dried green olives (Carolea cv.)

•Bigger depletion of antioxidants after drying at medium temperatures.•Higher antioxidant activity in dried green olives respect to the dried brined ones.•Contribution of water-soluble melanoidins to the total antioxidant activity.

The main objective of this paper was to evaluate the variation of qualitative parameters in dried olives and brined dried olives. Physical and chemical analyses and an investigation of new formed antioxidants were carried out on samples before and after treatments. The results of analyses reported a decreased content of total phenolic compounds after drying in both typologies of olives, with the biggest reduction at medium temperature. On the other hand, higher drying temperature increased the total antioxidant capacity of olives and this is probably related to the new formation of melanoidins. A further fractionation of these compounds confirmed its contribution to the overall reducing property of the extracts of dried olives. Brined olives were instead characterized by a lower amount of antioxidant constituents, particularly phenolics. They decreased in olive pulp due to its osmotic release in the brine during fermentation and successively by the oxidative reaction after drying.