Lipid oxidation and development of cholesterol oxides in pork during cooking and storage

Changes in lipid oxidation and development of cholesterol oxidation products during 6 days of refrigerated (4 degrees C) and 90 days of frozen (-10 degrees C) storage are reported in raw, broiled and pressure cooked pork. Results indicated significant (P<0.05) increases in all the lipid fractions due to cooking, but did not show much changes during both the storages. The TBA values also increased during storage. but the values were well below the threshold values of rancidity. Cholesterol oxidation products separated by thin layer chromatography were: cholestanetriol, 17-alpha hydroxycholesterol, 19-hydroxycholesterol, 7-ketocholesterol, cholesterol-alpha epoxide, cholesterol-beta epoxide and an unidentified fraction. All these fractions increased, while the unidentified fraction decreased simultaneously during cooking and storage. Changes due to broiling were more pronounced compared to pressure cooking and even frozen storage did not prevent cholesterol oxidation in pork.