Comparison of Antioxidant Capacities and Phenolic Compositions of Ayvalık Olive Oils from South Marmara and Mediterranean Regions in Turkey
Ayhan Dağdelen1, Gülcan Özkan2, Latife Dalgıç2, Saliha Onur Sermet2
1Balıkesir University, Faculty of Engineering and Architecture, Department of Food Engineering, Balıkesir, TURKEY
2Suleyman Demirel University, Faculty of Engineering and Architecture, Department of Food Engineering, Isparta, TURKEY

The research was carried out with Ayvalık olive cultivar from different locations, Ayvacık (South Marmara) and Fethiye (Mediterranean) regions in Turkey. Olive samples at the stage of ripening index between 5 and 6 were handpicked in 2012-2013 season. The olives were mechanically extracted at laboratory conditions by using two-phase batch equipment. 
Methanol:Water (80:20) was used for phenolic extraction of samples. The total phenols (TP) content of the extracts was determined according to the Folin-Ciocalteu spectrophotometric method. The spectrophotometric analysis was repeated three times for each type of extract. The results showed that Ayvacık samples of olive oil had 98,46 mg GAE/kg oil and Fethiye samples had 164,14 mg GAE/kg oil.
Free Radical Scavenging Abilities were determined with DPPH (2,2-diphenyl-1-picrylhydrazyl) method and were found between % 15,92 (Ayvacık) and % 15,74 (Fethiye) inhibition value.   
Phenolic compositions of samples were determined by using HPLC. 8 phenolic compounds were found as hydroxytyrosol, tyrosol, vanillic acid, vanilin, p-coumaric acid, ferulic acid, quercetin and luteolin. Cinnamic acid was the least phenolic in Fethiye samples with 0.05 ppm and was not found in Ayvacık samples. Tyrosol (9.77 ppm in Ayvacık samples and 16,18 ppm in Fethiye samples) and hydroxytyrosol (6,45 ppm in Ayvacık samples and 4,27 ppm in Fethiye samples). 
Key words: Olive oil, Total phenolic content, Free Radical Scavenging Activity, Phenolic composition