Evaluation of the Thermal Stability, Antioxidant Activity, Total Phenolics and Fatty Acids Profile in Some Edible Nut Oils(Pistachio,Walnut,Almond)

With regard to the significant functions of nuts in preventing cardiovascular diseases and certain kinds of cancer as well as their high consumption in our country, the present research was conducted to identify some characteristics of Iranian nut oils including walnut, almond, pistachio with cultivars Damavand, c.v.b12, Ahmad Aghaee with %4, Momtaz by measuring the total phenolic compounds using folin assay, identifying fatty acids profile by GC, oil oxidative stability at three different temperatures: / by Rancimat method and measuring other oxidative stability by Oven Test. Folin assay results showed that walnut consists the most phenolic compounds, then were pistachio and almond, respectively. Rancimat test results indicated that pistachio possessed the highest oxidative stability in each of three mentioned temperatures and then were almond and walnut, respectively. The results of the other oil oxidative stability showed the most oxidative stability among the mentioned oils and the conclusion of variation trend of peroxide index with less rate was in pistachio and then were almond and walnut, respectively. The important results of the fatty acids profile indicated that pistachio contained the most saturated fatty acids and the least saturated fatty acids belonged to walnut. Among the mentioned oils, almond oil had the least poly-unsaturated fatty acids and walnut had the most one. In addition, almond possesed higher oleic acid, then were pistachio and walnut, respectively. According to these findings and inspite of having high phenolic compounds in walnut oil compared with other mentioned oils, it is concluded that the profile of fatty acids has a more effective and crucial role in the stability of oils oxidation.