Bioactive Properties of Some Local And Foreign Olive Oils

Abstract

Nutrition profile is critical for a healthy life. In particular, some components in certain foods can directly affect human health by showing biological activity (bioactive) in the body. In this context, extra virgin olive oil is a food that has recently gained importance due to its positive effects on health. In this study, phenolic compound profiles (oleuropein, hydroxytyrosol, tyrosol, catechin, pinoresinol, luteolin, apigenin, caffeic acid, vanillic acid, t-ferulic acid, and p-coumaric acid), total phenolic content (TFC) and total antioxidant capacity (TAC) of 5 different extra virgin olive oils obtained from different olive varieties (Domat, Uslu, Arbequina, Taggiasca, Koroneiki) were investigated. The amounts of the individual phenolic compound in the oil samples were determined by a high-pressure liquid chromatography system (HPLC), while TFC and TAC were determined by using spectrophotometric methods. Hydroxytyrosol, as the major phenolic compound, was found at the highest content (129.375 mg/kg) in Koroneiki olive oil, whereas its lowest (14.485 mg/kg) content was found in Domat olive oil (P<0.05). Koroneiki olive oil also showed the highest content for tyrosol, while Uslu and Arbequina olive oils had the lowest contents for this compound (P<0.05). For pinoresinol, the maximum contents were found in Domat (16,817 mg/kg) and Koroneiki (15,160 mg/kg) samples, whereas the Uslu oils (5,260 mg/kg) exhibited the minimum content. Phenolic acids were found at minor levels in all samples. According to the spectrophotometric results, although the TFC level in Koroneiki olive oil was the highest (294.822 mg gallic acid equivalent (GAE)/kg), this value was not statistically different from the values in Domat (259.950 mg GAE/kg) and Uslu (284.267 mg GAE/kg) oils (P>0.05). Similarly, the difference between the TFC of Arbequina (208.962 mg GAE/kg) and Taggiasca (219.526 mg GAE/kg) oils were not significant (P>0.05). The results of TAC demonstrated that Koroneiki oil showed the highest (110.396 mg trolox equivalent (TE)/kg) value for antioksidan aktivity, while Taggiasca oil showed the lowest (58.465 mg TE/kg) value (P<0.05). The results of this study show that the investigated bioactive properties can be used as a distinguishing feature for olive oil from different olive varieties.