QUANTITATION OF CHOLESTEROL OXIDATION-PRODUCTS IN UNIRRADIATED AND IRRADIATED MEATS

A method to detect 7-ketocholesterol, cholesterol-5beta,6beta-epoxide, cholesterol-5alpha,6alpha-epoxide, 4-cholesten-3-one, 4,6-cholestadie n-3-one and 4-cholestene-3,6-dione in unirradiated and irradiated beef , pork and veal was developed by use of chloroform-methanol-water extr action, solid-phase extraction, column separation, thin-layer chromato graphy and gas chromatography. This method recovered 78-88% of the cho lesterol oxidation products and detected the cholesterol oxidation pro ducts at 10 ppb or higher. Irradiation of the meats to a dose of 10 kG y increased these compounds, except 4,6-cholestadien-3-one for all thr ee types of meat, over unirradiated, and except cholesterol-5alpha,6al pha-epoxide and 4-cholesten-3-one for the pork. All the cholesterol ox idation products in the unirradiated meats increased during storage at 0-4-degrees-C for 2 wk with some exceptions for the pork. The increas es of cholesterol oxidation products in stored irradiated meats were g reater than those in the unirradiated.