Determination of cholesterol oxidation products in raw and processed beef and pork preparations

摘要

The effect of pan-frying on the formation of cholesterol oxidation products (COPs) in different processed meat samples (beef patties, braised meat, and fillets of pork) was studied. Samples were pan-fried with or without addition of oil. Different unsaturated oils (olive oil, corn oil or partly hydrogenated plant oil) were used throughout the study. After extraction, seven toxicologi-cally relevant COPs were analyzed using LC-MS. Prior to heat processing up to 6.7 mg COPs/kg extracted fat could be detected in the raw material. Neither the cholestanetriol nor 25-hydroxy cholesterol, which are the most cytotoxic COPs in vitro, were detectable in any sample. Differences in the COPs contents were observed between beef (up to 16.5 mg/kg extracted fat) and pork (up to 22.2 mg/kg extracted fat) samples. In prepared samples higher COPs content was noted compared with raw samples. Generally, a certain order of COPs increase dependent on the plant oil used could be recognized: corn oil < partially hydrogenated plant oil < olive oil. It appears that short heating time, mild heating conditions, and the use of fresh and shortly stored raw materials keep COPs levels low.