Epoxyalkenal-trapping ability of phenolic compounds.

Lipid oxidation products have been shown to produce changes in food quality and safety as a consequence of carbonyl-amine reactions. Some of these reactions can be prevented by the use of phenolics, although the lipid-derived carbonyl trapping ability of phenolics is still poorly understood. In an attempt to fill this gap, the reactions of 4,5-epoxy-2-hexenal, 4,5-epoxy-2-heptenal, and 4,5-epoxy-2-decenal, with 2-methylresorcinol and 2,5-dimethylresorcinol were studied. These reactions produced diverse 1,3a,4,9b-tetrahydro-2H-furo[2,3-c]chromene-2,7-diols and 3,4,4a,9a-tetrahydro-1H-pyrano[3,4-b]benzofuran-3,7-diols, which were isolated and characterized by 1D and 2D nuclear magnetic resonance (NMR) and mass spectrometry (MS). The produced epoxyalkenal-phenol reaction was characterized and carbonyl-phenol adducts were produced firstly by epoxide-ring opening initiated by the attack of one phenolic hydroxyl group and, then, by addition of one aromatic phenol carbon to the carbon-carbon double bond of the epoxyalkenal. This reaction rapidly deactivated the most important reactive groups of epoxyalkenals, decreasing in this way their ability to modify amino compounds.