Fatty Acid and Sterol Composition of Oils Extracted from Pistachio, Walnut, Hazelnut and Almond Employing by Cold Press Method

Oils extracted from nuts by the cold press might be regarded as valuable oils due to their high yield, unique flavors characteristics. Due to the role of nuts in Iranian society regarding its high consumption, this preliminary study concerned with the fatty acid and sterol compositions of the oils extracted from the related nuts by cold press have been carried out. To define the chemical compositions of nut oils, four nuts consisting of pistachio, walnut, hazelnut and almond were collected from Kerman, Tuyserkan, Qazvin and Azarshahr areas respectively and the oils were extracted at 25°C using the cold press methods. Fatty acid and sterol compositions were determined using a gas chromatography equipped with a capillary column and Flame Ionisation Detector according to the defined methods of standard. The results showed that oleic acid was predominant fatty acid in hazelnut (83.3%), almond (67.6%) and pistachio (63.3%) oils while the linoleic acid had the highest concentration in walnut oil (52.5%). The analysis of the sterol fractions of the nonsaponifiable matters of the extracted oils indicated that the apparent β-sitosterol was the predominant sterol and covered 85-91% of the total sterol fractions in all the oils examined. The results showed that the oils extracted from nuts have desirable quantities of oleic and linoleic acids. The results also indicated the absence of trans acids. Due to the presence of high concentrations of oleic acid in hazelnut, almond and pistachio, these oils have a good stability against oxidation chain reactions.