Cholesterol oxidation process

Enrichment of processed food with plant material or plant extracts rich in polyphenols has two aspects in relation to human nutrition and human health. Food protected against oxidation has better keeping quality and will stay healthy longer since formation of toxic oxidation products, like cholesterol oxides, is being prevented (Britt et al., 1998). The other aspect is the beneficial effects of the intake of polyphenols on human health. Both of these aspects are, however, related to the availability of the phenolic substances. 

Smith LL, Teng JI, Kulig MJ, Hill FL. Sterol metabolism. XXIII. Cholesterol oxidation by radiation-induced processes. J Org Chem 1973 38 1763-1765. 

Chan, S.-H., Gray, J.I., Gomaa, E.A., Harte, B.R., Kelly, P.M., Buckley, D.J. 1993. Cholesterol oxidation in whole milk powders as influenced by processing and packaging. Food Chem. 

Galvin, K., Morrissey, P.A., Buckley, D.J. 1998b. Cholesterol oxides in processed chicken muscle as influenced by dietary a-tocopherol supplementation. Meat Sci. 48, 1-9. 

McCluskey, S., Connolly, J.F., Devery, R., O Brien, B., Kelly, J., Harrington, D., Stanton, C. 1997. Lipid and cholesterol oxidation in whole milk powder during processing and storage. /. FoodSci. 62, 331-337. 

Osada, K., Kodama, T., Cui, L., Yamada, K., Sugano, M. 1993b. Levels and formation of oxidized cholesterols in processed marine oils. J. Agric. Food Chem. 41, 1893-1898. 

Muench et al. (2005) studied the effect of high-pressure processing (400 or 800 MPa) on formation of cholesterol oxidation products in cooked sausages (cured and non-cured Bruehwurst). Application of high-pressure processing did not... 

A series of further transformations takes place in animals to transform C30 lanosterol to C27 cholesterol. In broad outline, the process involves first elimination of the methyl group located at C14 by an oxidative process to afford 14-desmethyllanosterol (5-1) a similar process then expels two methyl groups found at position 4 to give zymosterol (5-2) (Scheme 2.5). A series of enzyme-mediated steps in essence moves the double bond between rings B-C to C5 and reduces the double bond in the side chain to afford cholesterol (5-3). 

Sander, B. D., Smith, D. E., and Addis, P. B. (1988). Effects of processing stage and storage conditions on cholesterol oxidation products in butter and Cheddar cheese. J. Dairy Sci. 

To an ordinary observer like the present writer, it has seemed curious from the beginning that a reducing agent like ascorbic acid could assist in the chemical conversion of cholesterol into 11-oxysteroids, since this is an oxidative process— though the biochemists seem to be able to explain such things by juggling with oxidation-reduction potentials ... 

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