Cholesterol oxides in foods

Abstract

Cholesterol oxidation in foods yields oxides that show cytotoxic, atherogenic, mutagenic and carcinogenic properties suggesting that the intake of these compounds should then be examined criteriously. Whole milk powder, butter, fried hamburger, grilled beef and egg yolk, fresh, fried and powder, were analyzed in relation to cholesterol and their oxides 7±-hydroxycholesterol (7±-OH), 7²-hydroxycholesterol (7²-OH), 7-ketocholesterol (7-keto) and 25-hydroxycholesterol (25-OH), by HPLC. Cholesterol values varied from 22.81±9.00 mg/100 g (whole milk powder) to 1843.62±92.69 mg/100 g (egg yolk powder). The total values of the oxides derived from carbon-7 (7±-OH, 7²-OH and 7-keto) amounted 18.76±9.50 µg/g for whole milk powder, 34.56±11.63 µg/g for butter, 11.11 ±1.26 µg/g for fried hamburger and 22.84±8.43 µg/g for grilled beef. In fresh egg yolk neither 7-keto nor 25-OH were found. Levels of 9.46±0.15 µg/g for 7-keto were found in fried egg yolk and 110.54±11.82 µg/g for 7-keto and 112.67±13.52 µg/g for 25-OH in egg yolk powder. Many results here obtained were greater than those previously reported suggesting more detailled studies should be performed mainly in relation to food processing and storage.