Oxidative stability of cholesterol in whole egg powder

Abstract

Eggs are important as food and also as raw material for the food industry. However they show high levels of cholesterol, mainly when they are dehydrated. Cholesterol can be oxidized during processing and/or storage to cholesterol oxides which are toxics. The oxidative stability of cholesterol in commercial whole egg powder was evaluated by the occurrence of "free" 7-ketocholesterol (free 7-k) quantified by high-performance liquid chromatography, after total lipid extraction and separation on Florisil column. Free 7-k occurred in all samples analyzed (three different lots from five brands), 84,01±5,34 mug/g lipid (n=5). It was not possible to accompany cholesterol oxidation in whole egg powder stored until 224 days, at room temperature, but a significant correlation (r=0.8093) was observed between free 7-k and thiobarbituric acid reactive substances, attesting the actual oxidation of cholesterol to toxic keto derivative.