Oxidation of cholesterol in mayonnaise during storage

The oxidative stability of cholesterol in commercial mayonnaise under different storage conditions was evaluated by measuring cholesterol oxides (COs), 7-ketocholesterol (7-Keto), 25-hydroxycholesterol (25-OH), 7α-hydroxycholesterol (7α-OH) and 7β-hydroxycholesterol (7β-OH) using HPLC. Oxidation of cholesterol was indicated within about 15 days after manufacture by the presence of 7-Keto. Oxidation increased during storage at 4 and 25 °C (being greater at 25 °C) for 165 days in darkness, as indicated by the presence of 7-Keto, 25-OH, 7α-OH and 7β-OH. There was a strong correlation between COs and PV (peroxide value) [r2=0.95 (4 °C) and r2=0.96 (25 °C)] during the process of oxidation. The pattern of fatty acids was not affected during the period of the experiment. Temperature and time were important factors in the oxidative stability of cholesterol. Total formation of COs during 165 days was 20.3 μg/g at 4 °C and 30.2 μg/g at 25 °C.