Comparison of radiation-induced hydrocarbons formed in three irradiated oilseeds

Abstract

To investigate the effect of fatty acid composition and irradiation dose on the radiation-induced hydrocarbons, three oilseeds (i.e., peanut, sesame and flaxseed) were selected and irradiated at 2, 4, 6 and 8 kGy. The radiation-induced hydrocarbons were extracted using simultaneous distillation extraction (SDE) and analyzed by gas chromatography-mass spectrometry (GC-MS). The most abundant fatty acid in peanut, sesame and flaxseed oils was oleic, linoleic and linolenic acid, respectively. Nine radiation-induced hydrocarbons including 1,3-bis(1,1-dimethylethyl)benzene and eight products from palmitic, stearic, oleic and linoleic acid were detected in all irradiated samples, even at 2 kGy. Compared to irradiated sesame and flaxseed, irradiated peanut had more radiation-induced hydrocarbons at the same dose. There was a visible difference in radiation-induced hydrocarbon composition among the three oilseeds. The radiolytic hydrocarbons derived from oleic and linoleic acid were predominant for peanut and sesame, while only oleic acid for flaxseed. The fatty acids in flaxseed were more readily cleaved at the alpha-carbon position compared to peanut and sesame. In addition, the concentrations of all detected radiation-induced hydrocarbons in three oilseeds increased linearly with irradiation dose (R2 = 0.957–0.993). The irradiated oilseeds from three different species could be distinguished by hierarchical cluster analysis based on their radiation-induced hydrocarbons.