Effect of gamma irradiation and storage on the syrian olive cultivar Kaissy (Olea europaea) oil properties

The purpose of the current work was to evaluate the influence of gamma irradiation and storage period on the stability of physicochemical characteristics of olive oil. Olive (Olea Europaea) oil (OO) was extracted from fruits of Kaissy cultivar widely grown in Syria and treated with 1, 2 and 3 kGy doses of gamma irradiation, and stored at room temperature up to 36 months. Results indicated that gamma irradiation significantly (p<0.01) increased the oil acidity (acid value) (AV) (Oleic acid %), iodine value (IV), specification value (SV), and viscosity, and significantly decrease (p<0.05) the refractive index (RI), while no significant effect of irradiation was detected on peroxide value (PV). Lower doses of gamma irradiation (1 and 2 kGy) significantly decreased the TBA number (Thiobarbituric acid), whereas, the 3 kGy dose significantly increased the TBA number. During storage, there was a significant increase (p<0.01) in AV, PV, RI, TBA and viscosity of Kaissy Olive Oil (KOO) samples. However, during storage, a significant decrease (p<0.01) in SV of irradiated KOO samples was detected. The studied qualitative characteristics including AV, PV, IV, SV, RI, TBI and viscosity of olive oil were significantly influenced by gamma irradiation used doses and storage time.