Kinetic modelling of lipid hydroperoxide formation in pure triacylglycerides

Abstract: Lipid (per)oxidation is studied in various fields, ranging from biology, to pharmaceuticals, and foods. The lipid autoxidation cycle starts with the abstraction of a hydrogen next to a double bond of an unsaturated fatty acid. This radical reacts with oxygen, and a hydrogen donor to form lipid hydroperoxides, which are the first metastable reaction products, and can therefore be detected easily.¹ Our understanding of these chemical reactions can be deepened by kinetic modelling them. However, such approach requires the formation rate constants of hydroperoxides individually, which are not available yet.

In this study, we used NMR spectroscopy for the annotation and quantification of a wide range of (novel) individual hydroperoxides that were formed during the autoxidation of pure triacylglyceride standards at varying temperatures.^{2, 3} The obtained curves enabled us to kinetically model the formation of hydroperoxides. Our model included the intermediate radical species as well as the degradation of hydroperoxide catalysed by transition metals. The obtained set of pathways and kinetic parameters enables the comprehensive quantitative modelling of lipid oxidation in products with complex oil compositions.

References

1. Schaich, K. M., Lipid oxidation: new perspectives on an old reaction. In Bailey’s Industrial Oil and Fat Products,, 7th ed.; Shahidi, F., Ed. John Wiley & Sons, Ltd.: 2020.


2. Merkx, D. W.; Hong, G. S.; Ermacora, A.; Van Duynhoven, J. P., Rapid quantitative profiling of lipid oxidation products in a food emulsion by ¹H NMR. Analytical chemistry 2018, 90 (7), 4863-4870.


3. Boerkamp, V. J. P.; Merkx, D. W. H.; Wang, J.; Vincken, J.-P.; Hennebelle, M.; van Duynhoven, J. P. M., Quantitative assessment of epoxide formation in oil and mayonnaise by ¹H-¹³C HSQC NMR spectroscopy. Food Chemistry 2022, 390, 133145.