Croat. J. Food Sci. Technol. (2019) 11 (1) __ __ “ARTICLES IN PRESS” Croatian Journal of Food Science and Technology journal homepage: www.ptfos.unios.hr/cjfst/ Original scientific paper DOI: 10.17508/CJFST.2019.11.1.08 Chemical characterization and storage stability of extra virgin olive oil extracted from Derik Halhalı cultivar ESMAEIL GHANBARI SHENDI 1* , DILEK SIVRI ÖZAY 1 , MÜCAHIT TAHA ÖZKAYA 2 , NIMETI FEYZA ÜSTÜNEL 3 1 Hacettepe University, Department of Food Engineering, Ankara 06800, Turkey 2 Ankara University, Department of Horticulture, Ankara, 06110, Turkey 3 Nar Doğal Ürünler Tur. Tic. San. A.Ş. Ümraniye-İstanbul, Turkey ARTICLE INFO ABSTRACT Article history: Received: July 15, 2018 Accepted: March 21, 2019 Turkish olive cultivar known as “Halhalı” that is locally grown in Mardin (Derik) province, situated in the southeast Anatolia, was used for virgin olive oil (VOO) production. Halhalı olive was processed in the “Mobile Olive Oil Processing Unit” (TEM Oliomio 500-2GV, Italy) designed as the first mobile olive mill in Turkey. Some chemical and physical properties (colour, UV absorbance values, free fatty acid content, peroxide value, phenolic and tocopherol profiles) were determined and monitored during one year of storing in the dark at room temperature once in every three months. Results showed that up to the eighth month of storage, free fatty acid content, peroxide and UV- absorption values (K232 and K232 values) did not exceed the limits reported by International Olive Council (IOC) and olive oils were categorized as Extra Virgin Olive Oil (EVOO). Colour changed from green to yellow and UV absorbance values altered during storage. Total phenol and vitamin E (α- tocopherol) contents decreased by 18% and 16.38%, respectively. Luteolin and apigenin were the most abundant phenolics and their contents decreased up to 22% and 28% during storing, respectively. Keywords: olive oil, Halhalı, phenolic compounds, tocopherol, storage. Abbreviation: EVOO= Extra Virgin Olive Oil, IOC= International Olive Council, VOO= Virgin Olive Oil. Introduction  Turkey is second in the number of olive trees (190 million) after Spain. Southeastern Anatolia located in upper Mesopotamia is the origin of olive trees, there are 91 registered olive cultivars in National Olive Collection in Olive Research Institute, Izmir. Derik Halhali is one of the six olive cultivars (Derik Halhali, Belluti, Hursuki, Mavi, Melkabazi and Zoncuk) cultivated in Derik district. The total number of the olive trees are 150,000 with the 8% of total olive trees, but 80% is Derik Halhalı. Halhalı fruits are medium sized with large seeds and oil content is between 21-27%. It has moderate yield with high periodicity and it is usually processed as table olive (Anonymous, 2016). * Corresponding author E-mail: esi.1361@gmail.com Olive oil differs among other edible oils due to high oleic acid, phenolics, vitamins, and other minor compounds. For this reason, it has unique nutritional value and sensory properties which do not exist in others. Virgin olive oil (VOO) is obtained from olive fruits by using only physical procedures, therefore it is ready to consume without refining processes. Thus, while other refined edible fats and oils might have trans fatty acids and heat contaminates such as 3-MCPD, 2-MCPD and glycidyl esters which are a risk factor in terms of food safety, olive oil does not contain these substances. Chemical composition varies in a broad range depending on cultivar, ripeness degree, ecologic conditions, growing region, processing techniques and storage. Free fatty acid content, peroxide value and oxidative rancidity increases, while total polyphenols, tocopherols and