H. Fallah - Department of Clinical Biochemistry, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Islamic Republic of Iran.
S. Khorasani - Depatment of Food Science and Technology, Shahid Bahonar University of Kerman, Kerman, Islamic Republic of Iran.
A. Mohammadi - Department of Clinical Biochemistry, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Islamic Republic of Iran.
M. H. Azizi - Department of Food Science and Technology, Tarbiat Modares University, Tehran, Islamic Republic of Iran.
M. Barzegar - Department of Food Science and Technology of Tarbiat Modares University, Tehran, Iran
Z. Hamidi Esfahani - Department of Food Science and Technology, Tarbiat Modares University, Tehran, Islamic Republic of Iran.

One way to protect food and nutrients is to use gamma irradiation. Gamma rays are capable of influencing fatty acids, thus, this research was carried out to test the impact of using gamma rays on pistachio stored for six months and to determine the optimal effective dose of gamma with no negative impact on the amount of fatty acids in different types of pistachios. Three doses including ۳, ۵, and ۹ kGy of gamma rays were used to protect and store different pistachios in Kerman. After being exposed to gamma rays, the pistachios were stored for six months in a storehouse at ۵°C and (۹-۴۳%) RH. Every three months, the samples were analyzed. The greatest amount of oleic acid was found in Ahmad Aghaei pistachio type (۶۲.۰۸%) followed by Ohadi (۶۱.۰۳%), Kaleh Qouchi (۵۹.۸۳%), and Akbari (۵۵.۸۰%) types (P< ۰.۰۵). Over time, oleic acid and unsaturated fatty acids decreased in all of the control and test samples. After three months of storing, in Ahmad Aghaei pistachios irradiated with a ۳ kGy dose of gamma, the amount of oleic acid fatty acid was ۴۵.۱۵%. With ۵ kGy dose, after three months, oleic acid fatty acid was ۶۶.۶۵%, and with ۹ kGy dose after three months, it was ۵۹.۹۰%. Therefore, it can be concluded that the use of irradiation doses of ۵ and ۹ kGy affects the increase of unsaturated and derived fatty acids, thus, the dose of ۵ kGy irradiation is most appropriate.

Ahmad Aghaei pistachio, Fatty Acid Profile, Gamma Irradiation, Oleic acid, Storage.