Cholesterol oxidation during storage of UHT-treated bovine and caprine milk

Degradation of cholesterol during storage of UHT treated bovine and caprine milk was assessed. Cholesterol contents were 11.78 and 8.51 mg 100 mL−1, respectively. During storage for 6 months, the cholesterol amounts decreased irrespective of the milk type and storage conditions. The total contents of cholesterol oxidation products (COPs) observed in raw bovine and caprine milk were 50 and 38 μg 100 mL−1, respectively. Regardless of the type of milk and storage conditions, a significant increase in the total amounts of oxysterols was observed. After 6 months storage of UHT bovine milk, the content of COPs increased to 217 and 248 μg 100 mL−1 for milk stored at 4 °C and 20 °C, respectively, whereas in caprine milk the amount increased accordingly to 160 and 249 μg 100 mL−1. These results confirmed formation of oxysterols in UHT milk during storage, with temperature and time being the most important factors.