Formation of oxygenated α,β-unsaturated aldehydes and other toxic compounds in sunflower oil oxidation at room temperature in closed receptacles

The study of the volatile components presents in the headspace of 27 sunflower oil samples, stored over different periods of time, at room temperature in closed receptacles, in presence of limited amounts of air, has been carried out by solid phase microextraction (SPME) followed by gas chromatography/mass spectrometry (GC/MS). The composition of the headspace of the studied samples is highly varied, ranging from the characteristic of non-oxidized oils to that of oils with a high oxidation level. Among the detected compounds are alkanals, (E)-2-alkenals, 2,4-alkadienals, ketones, acids, esters, alcohols, as well as aliphatic and aromatic hydrocarbons. In samples having a certain oxidation degree it is worth noting the presence of a significant number of genotoxic and cytotoxic oxygenated α,β−unsaturated aldehydes (OαβUΑs), such as 4-hydroxy-2-nonenal, 4-oxo-2-nonenal or 4,5-epoxy-2-decenal, which have been considered responsible for various degenerative diseases which are widespread nowadays; some of these compounds are described in this manuscript for the first time as coming from edible oil oxidation at room temperature. In addition, it has been found the occurrence of polycyclic aromatic hydrocarbons (PAHs) in concentrations in line with the oxidation level of the sample.