Effect of Gamma Radiation on Quality Attributes of Groundnut Oil in the Presence of Antioxidants

Exposure of groundnut oil to gamma radiation was investigated. The scope of the study elaborates the interactions taking place between antioxidants and gamma radiation when applied to edible oils. The objective is to assess the impact of gamma radiation on the quality attributes of groundnut oil in the presence of antioxidants. The groundnut oil was divided into three categories, namely, Category (1) that was (control1-untreated oil), Category (2) that was (control2 treated oil) which is exposed to different doses of gamma radiation in the absence of antioxidants and Category (3) was treated with different levels of antioxidants (Vitamins E and C) at levels of (50, 150 and 200 ppm) followed by exposure with different doses of gamma radiation (5, 10, 15 and 20 kGy). All samples were subjected to chemical analyses. . Groundnut oil samples treated with gamma radiation without antioxidants showed significant increases (P0.05) of 1.03 to 1.99, 11.22 to 23.77 and 1.60 to 13.20 forfree fatty acids (FFAs), peroxide value (PV) and anisidinevalue (AV) values respectively. On the other hand, the iodine value (IV) showed significant decreases (from 96.25 to 89.46 at P0.05) with increasing radiation doses. For Category 2 oils with vitamin C levels of (50, 150, 200ppm), the results showed significant increases (P0.05) in FFA, PV and AV with increasing radiation doses ranging, 1.03 to1.87, 11.22 to 18.77 and 1.60 to 12.21 for FFA, PV and AV respectively. With the addition of vitamin E (50-150-200ppm) the results showed significant decrease (P0.05) from 1.99 to 1.10, from 23.77 to 14.45 and from 13.20 to 8.93 for FFA, PV and AV, respectively. According to the results, it was noted that exposing oil to gamma radiation (greater than10KGy) led to deterioration of oils quality. Presence of antioxidants in the oil reduced the effect of gamma radiation within limits. Vitamin E compared to vitamin C as an antioxidant showed better stability to radiation. Finally, it can be recommended that avoiding exposure of oils seeds, as a main source of edible oils, to gamma radiation are preferred, unless the latter is used for specific objectives (e. g. disinfestations from fungi or insect). The study suggests that exposure of fatty foods or food containing fats to radiation as a means for cold sterilization can further be investigated.