Phenolic trapping of lipid oxidation products 4-oxo-2-alkenals

• Published in: Food chemistry 2018-02, Vol.240, p.822-830
• Main Authors: Hidalgo, Francisco J., Aguilar, Isabel, Zamora, Rosario
• Format: Article
• Language: English
• Subjects: 4-Oxo-2-alkenals; Aldehydes; Carbonyl-amine reactions; Carbonyl-phenol reactions; Lipid oxidation; Lipids - chemistry; Maillard reaction; Oxidation-Reduction; Reactive carbonyls; Resorcinols
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2017.08.027

•Phenolics rapidly trap oxoalkenals produced as a consequence of lipid oxidation.•The reaction has been characterized and the formed products have been identified.•Tetrahydrofuro[2,3-b]benzofuran-2,6-diols were major reaction products.•Benzofuran-6-ols and chromane-2,7-diols were also produced.•The produced reaction reduced the activity of reactive groups of oxoalkenals. The reaction between 4-oxo-2-alkenals (fumaraldehyde, 4-oxo-2-hexenal, and 4-oxo-2-nonenal) and phenolic compounds (resorcinol and 2-methylresorcinol) was studied to characterize the trapping ability of phenolic compounds for these lipid oxidation products. The reaction occurred rapidly under neutral or slightly basic conditions and different carbonyl-phenol adducts were produced. However, these compounds were unstable and their stabilization had to be achieved by means of either acetylation or reduction with sodium borohydride. Three different kinds of adducts were isolated and characterized by using mass spectrometry (MS) and 1D and 2D nuclear magnetic resonance spectroscopy (NMR). They were benzofuran-6-ols, 2,3,3a,8a-tetrahydrofuro[2,3-b]benzofuran-2,6-diols, and chromane-2,7-diols. Most of them were produced as mixtures of diasteromers and all of them had a carbonyl group in a free form or as hemiacetal. A reaction pathway that explains the formation of these compounds is proposed. These results provide the basis to understand the removal of 4-oxo-2-alkenals by phenolic compounds in foods.