Effect of Spanish style processing on the phenolic compounds and antioxidant activity of Algerian green table olives

The study was carried out on seven Algerian olive cultivars to report the effect of Spanish style processing on individual and total phenolic compounds and the changes that occur in antioxidant capacity. The results indicate that the treatment leads to losses in phenolic contents which are cultivar dependent. Sigoise is the least affected variety (12.25%) and Azzeradj from Seddouk the most affected one (94.80%). The phenolic profile shows drastic changes after processing. Hydroxytyrosol is dominant in processed olives (14.42-545.42 mg·100 g-1) while oleuropein is the major phenolic compound in fresh olives (994.27 mg·100 g-1). As a consequence to the loss in phenolic content, substantial reductions in the antioxidant activities of the extracts are noted. They are estimated to be 13.12-92.75% in scavenging activity against the DPPH radical, 37.78-93.98% in reducing capacity, 59.45-97.94% in the hydrogen peroxide radical and 7.26-51.66% in the inhibition bleaching of β-carotene. Among the processed varieties, only Sigoise presented a positive value of RACI (relative antioxidant capacity index).