Comparative study of volatile components of soybean oil exposed to heating, ionizing and non-ionizing radiation

Heating and various radiation treatments have been widely used in the storage and processing of oilseeds. To compare the degradation effects of heating and different radiation treatments on oils, refined soybean oil was heated or radiated with γ-rays, microwave, ultraviolet and sunlight, while the oxidation indices, fatty acid composition and volatile constituents of the oils were analyzed. The results showed that all treatments had no significant effect on acid value and fatty acid composition, but oxidation indices (peroxide value, K232 and K268) were increased, especially for samples subjected to γ-rays and microwave radiation. The volatile components were analyzed using simultaneous distillation extraction combined with gas chromatography-mass spectrometry (SDE/GC-MS). A total of 82 volatile compounds were identified, including 18 alkanes, 19 alkenes, 30 aldehydes, 5 ketones, 4 alcohols, 2 furans and 4 benzenes. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) showed that there were significant differences in the volatile composition profiles of the oils after different treatments. The oils treated with gamma irradiation contained more alkenes, those treated with microwave radiation were rich in aldehydes, and those treated with sunlight radiation contained more alkanes. •Soybean oil was treated with heat, ionizing and non-ionizing radiation.•γ-ray and microwave radiation markedly increased the total volatiles in soybean oil.•Volatile profiles of soybean oil varied greatly after different radiation treatments.•Distinct from non-ionizing radiation, ionizing radiated oils contain more alkenes.•Oil samples can be distinguished by principal component analysis and cluster analysis.