Cholesterol oxidation products : analytical methods and levels in sweets containing heated butter oil

Abstract: Various methods are used to analyse cholesterol oxidation products (COP) due to the unavailability of a standard method. In order to select a suitable method for the enrichment of COP, three methods of saponication (A – C),and transesterication (D) of tallow with three levels (5,10 and 20 µg) of spiked COP, were evaluated. Further enrichment of COP was done by solid phase extraction, quantied by GC, and confirmed by GC–MS. The in-house method A, and method D, showed the best results among the four methods evaluated. The recoveries at all levels of spiked COP were generally higher than 60% in method A. The recoveries of all spiked COP at 5 µg level were consistently lower in method D compared with method A. From the results of this study it can be concluded that method A may be more suitable for the analysis of very low levels of COP in foods. Ghee (clarified butter oil), a major ingredient in Indian sweets, is an important source of saturated fatty acids, cholesterol and COP that are considered as risk factors for atherosclerosis. The high frequency of atherosclerotic complications reported among the Indian immigrants in England prompted determination of lipids and lipid oxidation status of a ghee sample and fifteen Indian sweets that are available in London supermarkets. The fatty acid profile of the samples shows saturated fats (about 73%), mainly composed of myristic, palmitic and stearic acids, except in two samples, which had levels of oleic acid in excess of 60%. TBARS values ranging from 19 to 260 µg/100 g might be due to the different oxidative status of different sweets samples. Cholesterol (approximately 0.22%) was the main sterol in all samples, except two where unspecified oils were used instead. Variation of total COP was from 0.94 to 38.41 µg/g sample. Some of these sweets may be a source of considerable amounts of saturated fatty acids, cholesterol and COP in the diet that possibly contribute to atherosclerosis.