Chemical characteristics and antioxidant activity of olive oils from Turkish varieties grown in Hatay province

Monovarietal virgin olive oil from five different Turkish varieties (Eğriburun, Karamani, Halhalı, Saurani and Haşebi) from Hatay province which were harvested on three different occasions have been analyzed to evaluate minor components (phenolic compounds, tocopherols and pigments), fatty acid profiles and antioxidant activity in order to determine the effects of both the nature of the variety and the time of harvest. The high total phenolics, secoiridoid aglycones, α-tocopherol and antioxidant activity of Saurani variety makes the oil of this variety superior to other varieties analyzed in this study. After evaluating the correlation matrix of the data set, the variables such as secoiridoids (3,4-DHPEA-EDA; 3,4-DHPEA-EA; p-HPEA-EDA and p-HPEA-EA), some of the phenolic compounds (hydroxytyrosol, vanillic acid and luteolin) and oxidation parameters (beta carotene bleaching activity, peroxide value and free fatty acids) were finally decided as the three factors which led to explore the underlying pattern of relationships by using principal component analysis.

► The varieties containing high levels of α-tocopherol, luteolin and h-tyrosol showed good levels of antioxidant activity in terms of TEAC. ► The variables such as secoiridoids and oxidation parameters were found convenient parameters in grouping the varieties for their similarity. ► It is advisable not to delay olive harvest as the levels of beneficial minor components decrease when the oils extracted from later harvested olives.