Discrimination of Turkish Gemlik virgin olive oils by growing regions and environmental conditions

Geographic origins together with environmental conditions (temperature, rainfall, humidity, altitude) during harvest, could alter the olive oil quality, nutritional value, and traceability. The impact of geographic region (Bursa PDO, Hatay, Mersin, and Izmir NPDO) and conditions at harvest years (2016 and 2017) on the quality and traceability of Gemlik virgin olive oils were investigated. Environmental conditions (high temperature and relative humidity, low rainfall) resulted in low quality due to increase in FFA, linoleic acid, PUFA, Δ7-stigmastenol, stigmasterol and total sterols in oils obtained from southeast (Hatay and Mersin) NPDO regions. Bursa PDO and Izmir NPDO Gemlik virgin olive oils were high in oleic acid, MUFA, hydroxtytyrsol, tyrosol, antioxidant activity and, ∆5-avenesterol and discriminated by 99% accuracy with discriminant analysis. PCA and DA can easily detect and distinguish differences in virgin olive oils quality and purity coming from different growing regions and subjected to inverse environmental conditions. Bursa PDO and Izmir NPDO growing regions have better conditions for Gemlik olives cultivation to obtain high quality and oxidative resistant Gemlik virgin olive oils.