1H NMR study of cholesterol autooxidation in egg powder and cookies exposed to adverse storage

The level of cholesterol oxides depends on the production and storage conditions for food. We studied the effect of prolonged storage, heat and diffuse daylight on spray-dried egg powder and cookies containing a large amount of cholesterol. The cholesterol oxides were isolated by chromatographic procedures, and were identified by recording 1H NMR spectra of selected HPLC fractions. Autooxidation was quite slow, when the sample was stored in a freezer at -20°C. Diffuse daylight increased the amounts of b-epoxides of cholesterol, whereas heating caused a sharp increase in C-7 oxidised cholesterol derivatives. Extent of cholesterol autooxidation depended on storage conditions.