Phenolic Compounds and Peroxide Parameters of Olive Oils Obtained from Local Varieties

Olive oil is known not only for its bitter and fruity taste, but also for its health potential, which is assumed to be due to its phenolic composition. The study was conducted to evaluate the effect of seasonal variation and variety on the total phenolic content, peroxide values and phenolic composition of olive oil. During the two consecutive production seasons of 2019 and the 2020, total phenolic content, peroxide value and phenolic compositions, which are among the quality parameters of the olive oils obtained from the fruits of eight local olive varieties grown in the Derik district of Mardin province located in southeastern Anatolia, Turkey, were analyzed. The highest total phenol content in the oils was recorded as 564 mg GAE/kg in the 'Belloti' variety in the 2020 production season, while the lowest total phenol content was detected as 122 mg GAE/kg in 'Derik Halhal & imath;' variety harvested in the 2019 production season. Results showed that seasonal climate fluctuations did not have a significant effect on the peroxide value, but they change according to varieties. It has been shown that olive oils of all local varieties grown in Derik district have a significant potential in terms of phenolic composition. It has been observed that this potential is especially higher in some varieties including 'Mavi', 'Belloti', 'Hursuki' and 'Zonc & imath;k'. According to the data obtained, the polyphenol content of olive oils from varieties harvested in the cool and rainy production season is lower than those harvested in the dry and hot season. Therefore, seasonal change and olive variety affect the polyphenol composition of olive oils extracted from olive varieties grown in a region.