Oxidation of cholesterol in butter during storage – effects of light and temperature

The objective of this study was to determine whether the exposure of three types of butter to different light and temperature conditions during a storage period of 6 weeks would result in a significant increase in cholesterol oxidation products (COPS) and, in addition, to assess whether a relationship exists between the amount of cholesterol oxides, the light source, the storage temperature and the type of butter. As standard indicator substances, 25-hydroxycholesterol, 7-ketocholesterol, 7β-hydroxycholesterol and 7α-hydroxycholesterol were used, and their prevalence was assessed using an HPLC method. With the exception of UV-light at room temperature, negligible increases in the formation of cholesterol oxides were detected in the first 3 weeks of storage. However, it was remarkable that in all three types of butter at refrigerator temperatures, a special light for food contributed more to the development of COPS than did a daylight lamp.