INTRODUCTION Extra virgin olive oil is a product containing high nutritional quality and has great benefits for consumers. Refined olive oil is the most valuable oil because has the potential effects on human health. So, these two types of oils are categorized as functional food oils 1 . It also has excellent organoleptic characteristics (Aroma & Taste) and antioxidant properties 2 . According to trade standard of international olive oil council, ORIENTAL JOURNAL OF CHEMISTRY www.orientjchem.org An International Open Free Access, Peer Reviewed Research Journal ISSN: 0970-020 X CODEN: OJCHEG 2015, Vol. 31, No. (3): Pg. 1735-1739 A Rapid Method for Detection of Refined Olive Oil as Adulterant in Extra Virgin Olive Oil by Differential Scanning Calorimetry MARYAM KARBASIAN 1 , MOHAMMAD HADI GIVIANRAD 2 *and YOUSEF RAMEZAN 1 1 Department of Food Sciences & Technology, Faculty of Advanced Sciences & Technology, Pharmaceutical Sciences Branch, Islamic Azad University, Tehran, Iran. 2 Department of Marine Chemistry, Science and Research Branch, Islamic Azad University, Tehran, Iran *Corresponding author; E-mail: givianradh@yahoo.com http://dx.doi.org/10.13005/ojc/310354 (Received: April 04, 2015; Accepted: June 19, 2015) ABSTRACT Extra virgin olive oil (EVOO) is expensive oil, due to unique specification and its high quality among other edible oils; it might be mixed with other oils. The aim of this research was to identify the added refined olive oil (ROO) to extra virgin olive oil. One sample of each oil was analyzed, admixtures of EVOO: ROO were prepared at different ratios (50:50 ,60:40, 70:30, 80:20, 90:10 and 95:5 w/w). To identify this adulteration, exothermic and endothermic thermograms were investigated. The results indicated that by increasing refined olive oil, onset temperature (T on ) was increased from -61.08 to -56.16 °C; also, offset temperature (T off ) decreased from 19.09 to 12.57 °C. Also results showed that when the ROO ratio increased then the enthalpy average values of both exothermic and endothermic curves were declined. Chemical tests were performed in parallel to better understanding these changes in curves. Key words: DSC; Extra virgin olive oil; Refined olive oil; Adulteration; Thermograms. olive oil has the highest oleic acid content after canola oil 3 . Olive oil has a lot of tocopherols like Capparis spinosal oil seeds 4 . Extra virgin olive oil is a type of oil which is an extracted from fruits of olive trees using mechanical methods or other tools and instruments. Using thermal actions or any extra process such as decanting or centrifuge that changes extra virgin olive oil specification is absolutely prohibited, extra virgin olive oil is rich in natural antioxidant such as phenols, tocopherols and oleic acid. This fatty acid is more resistant than