Preliminary Phytochemical, Fatty Acid, and In Vitro Antioxidant Characterization of the ‘Butko’ Olive (Olea europaea L.) Genotype from the Eastern Black Sea Region of Türkiye

Compositional data on the ‘Butko’ olive genotype (Olea europaea L.) from Artvin, Eastern Black Sea Region of Türkiye, remain limited, with no prior study integrating pomology, phenolic profiling, antioxidant capacity, and fatty acid composition. This study characterized these traits in fresh fruit. Mean fruit weight was 2.61 ± 0.20 g and length was 20.41 ± 1.20 mm. Methanolic extracts contained 561.33 ± 9.45 mg GAE/100 g total phenolic content and 51.36 ± 3.40 mg QE/100 g total flavonoid content. Ferric reducing antioxidant power was 46.20 ± 2.31 µmol FeSO4·7H2O/g, and DPPH SC50 was 1.15 ± 0.05 mg/mL (~0.10 mM). GC-FID analysis showed oleic acid dominated the fatty acid profile (69.37%), with linoleic (12.80%) and linolenic (0.44%) acids as minor constituents; saturated fatty acids totaled 14.82%, and squalene tentatively accounted for 1.02%. Among 26 phenolic standards screened by HPLC-PDA (excluding oleuropein), only catechin, epicatechin, luteolin, and vanillic acid were quantified. These results provide a comprehensive compositional baseline for the ‘Butko’ genotype, revealing a favorable fatty acid and phenolic makeup that highlights its potential as a functional food and valuable regional genetic resource.