Effects of frying and storage on cholesterol oxidation in minced meat products

The presence of cholesterol oxidation products (COP) in the diet is a healt h concern for their various known adverse effects. It is important that the generation of COP be assessed during different stages of production, handl ing, and storage of meats and meat products so that relevant measures can b e taken to minimize the production of COP. In a preliminary study, we inves tigated the content of COP in the lipids of raw meatballs (50% pork + 50% b eef), prefried meatballs (50% pork + 50% beef), raw hamburger (100% beef), and prefried burger (50% pork + 50% beef). Six of the common COP, viz. 7 al pha- and 7 beta-hydroxycholesterol, 7-ketocholesterol, 5 alpha,6 alpha-epox ycholestanol, 5 beta,6 beta-epoxycholestanol, and cholestanetriol, were ana lyzed by gas chromatography (GC) and GC-mass spectroscopy. The total conten t of these COP was in the range of 7 to 10 mu g/g lipids in raw meatballs, prefried meat balls, and raw hamburger, after frying these samples for cons umption. The prefried hamburger had ca. 8 mu g/g lipids of the total COP be fore trying, and this amount increased to 29 mu g/g lipids after frying. Du ring the storage of this fried sample, the total COP increased to 42 and 50 mu g/g lipids, after 1 and 2 wk of storage, respectively. The results of t his study show that freshly prepared meat products are a minor source of CO P in the diet. However, if semiprepared frozen meat products are fried once and then stored for future consumption, the levels of COP can increase con siderably, and this may be of concern for certain groups of consumers.