Quantitative assessment of epoxide formation in oil and mayonnaise by 1H-13C HSQC NMR spectroscopy. (1st October 2022)

• Record Type: Journal Article
• Authors: Boerkamp, Vincent J.P.; Merkx, Donny W.H.; Wang, Jianli; Vincken, Jean-Paul; Hennebelle, Marie; van Duynhoven, John P.M.
• Is Part Of: Food chemistry. Volume 390(2022)
• Publication Date: 2022-10-01
• Subjects: Epoxides -- Lipid oxidation -- Bulk oil -- Mayonnaise -- HSQC NMR -- Mechanistic insight; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2022.133145
• Languages: English
• ISSNs: 0308-8146

Abstract

Graphical abstract: Highlights: Epoxides can be quantified reproducibly and sensitively by HSQC NMR. Lipid hydroperoxides, aldehydes, and epoxides can be quantified simultaneously. Epoxides appear to be primarily formed via alkoxyl radicals. Epoxides have a limited potential as an early oxidation marker. Quantification of epoxides is critical for resolving lipid oxidation pathways. Abstract: Lipid oxidation is detrimental for the quality of oil-based foods. Historically, lipid oxidation research focussed on hydroperoxides and aldehydes, but a third class, the epoxides, have been proposed to resolve observed mechanistic anomalies. Here, we developed a 2D 1 H- 13 C HSQC NMR spectroscopic method to quantify epoxides in food in a reproducible (relative standard deviation ≤11.6 %) and sensitive (LoQ 0.62 mmol/kg oil) manner. Lipid hydroperoxides, aldehydes, and epoxides generated in rapeseed oil and mayonnaise were quantified over time by NMR. Epoxides accounted at most for 10–40 % of the products. They were formed after hydroperoxide accumulation, most likely primarily via alkoxyl radical intermediates, which limits their potential as an early oxidation marker. As 99 % and ∼60 % of the epoxide signal intensities were assigned in a fatty acid and sub-structure specific manner, respectively, our quantitative HSQC method will enable unravelling and quantitative modelling of lipid oxidation mechanisms.