Volatile compounds generated in corn oil stored at room temperature. Presence of toxic compounds
2014
Goicoechea, Encarnación | Guillén, María D.
Solid Phase Microextraction (SPME) followed by GC/MS was employed to study the headspace composition of corn oil (maize oil) samples stored at room temperature in closed receptacles with limited amounts of air for different periods of time. Samples with a high oxidation level showed the presence of typical secondary volatile oxidation compounds such as alkanals, 2‐alkenals, 2,4‐alkadienals, acids, alcohols, ketones, alkylfurans, and lactones. Aldehydes were the most numerous group; however, acids, which were fewer in number, showed the highest abundances. The high number of lactones detected is also noteworthy. In agreement with corn oil composition, those volatiles derived from linoleic acyl groups appeared in the highest abundances. The detection of two groups of toxic compounds, whose rise in concentration corresponded with the oxidation level of the samples, was remarkable. There were, on the one hand, alkylbenzenes and mono‐ and poly‐cyclic aromatic hydrocarbons (PAHs) of low molecular weight, such as toluene, naphthalene, and fluorene. On the other hand, there were oxygenated α,β‐unsaturated aldehydes like 4‐hydroxy‐2‐nonenal, 4‐oxo‐2‐nonenal, and 4,5‐epoxy‐2‐decenal brought about by the oxidation of omega‐6 polyunsaturated acyl groups (linoleic), and, in much lower proportions, 4‐hydroxy‐2‐hexenal and 4,5‐epoxy‐2‐heptenal coming from omega‐3 ones (linolenic). Practical applications: The identification and quantification of such a great number of volatile compounds coming from corn oil can be very helpful for other researchers who study the degradation of this vegetable oil or other kinds with similar proportions of acyl groups.
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