2,4-Alkadienal trapping by phenolics.

Phenolics can trap lipid-derived reactive carbonyls as a protective function that diminishes the broadcasting of the lipid oxidative damage to food macromolecules. In an attempt to clarify the trapping of 2,4-alkadienals by phenolics, this study analyzes the reactions of 2,4-hexadienal, 2,4-heptadienal, and 2,4-decadienal with 2-methylresorcinol. These reactions produced ( E )-4-(alk-1-en-1-yl)-8-methyl-2,7-bis(prop-1-en-2-yloxy)chromanes, which were isolated and characterized by 1D and 2D NMR and MS. Carbonyl-phenol adduct formation was favored at pH > 7 and moderate temperatures (25–80 °C). Adducts were quantified and shown to be produced as a mixture of diastereomers. Diastereomers 2 R ,4 S plus 2 S ,4 R were formed to a higher extent than diastereomers 2 R ,4 R plus 2 S ,4 S under the different conditions assayed, although activation energies ( E a ) for the formation of all of them was mostly the same (∼62 kJ·mol −1 ). These results show that phenolics can trap 2,4-alkadienals and provide the basis for the later detection of the formed adducts in food pro[ducts. [ABSTRACT FROM AUTHOR]