Abstract
The level of oxysterols in animal products depends on the temperature used in food processing, duration of heating, and storage time and conditions. High temperature, oxygen, exposure to light, chemical composition of the product and low level of antioxidants accelerate the formation of cholesterol oxidation products (COPs). Also the high content of polyunsaturated fatty acids in meat and eggs favours the formation of oxysterols. Dairy products are characterized by the lowest content of COPs of all animal products. The most common oxysterols present in products of animal origin are 7-ketocholesterol, 20α-hydroxycholesterol, 25-hydroxycholesterol and α, β-epoxycholesterol. Numerous studies have confirmed the adverse effects of COPs on animal and human health. They exhibit mutagenic, carcinogenic, angiogenic and toxic action, damage cell membranes, and inhibit cholesterol biosynthesis. The use of certain antioxidants in animal nutrition limits the formation of COPs during technological processing of meat, eggs and milk, as well as during storage of fresh products. The excessive oxidation of cholesterol can be additionally prevented through the use of appropriate packaging that limits oxygen and light exposure.