INFLUENCE OF FREE-RADICALS AND OTHER FACTORS ON FORMATION OF CHOLESTEROL OXIDATION-PRODUCTS IN SPRAY-DRIED WHOLE EGG

Factors influencing formation of cholesterol oxidation products (COPS) in spray-dried whole eggs, particularly free radicals generated during the combustion process, were investigated. Total COPS formed in products dried in the presence of free radicals (by using a gas burner or addition of prooxidants into an electric heating system) were approximately 2-5 times greater than those in powders processed by an electric heating system. Addition of antioxidants (tertiary butylhydroquinone and oleoresin rosemary) did not significantly affect (P < 0.05) the formation of COPS in eggs spray-dried with direct gas-fired heating during processing and/or storage. Room temperature storage significantly promoted (P < 0.05) further formation of COPS regardless of the initial content of COPS in the egg powders. The pathway of cholesterol oxidation initiated by oxides of nitrogen appeared to be similar to the hydroperoxide-induced free radical reaction.