Analysis of free and esterified sterols in vegetable oils
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In vegetable oils, phytosterols occur as free sterols or as steryl esters. Few analytical methods report the quantification of esterified and free sterols in vegetable oils. In this study, esterified and free sterols were separated by silica gel column chromatography upon elution with n-hexane/ethyl acetate (90∶10 vol/vol) followed by n-hexane/diethyl ether/ethanol (25∶25∶50 by vol). Both fractions were saponified separately and the phytosterol content was quantified by GC. The analytical method for the analysis of esterified and free sterols had a relative standard deviation of 1.16% and an accuracy of 93.6–94.1%, which was comparable to the reference method for the total sterol analysis. A large variation in the content and distribution of the sterol fraction between different vegetable oils can be observed. Corn and rapeseed oils were very rich in phytosterols, which mainly occurred as steryl esters (56–60%), whereas the majority of the other vegetable oils (soybean, sunflower, palm oil, etc.) contained a much lower esterified sterol content (25–40%). No difference in the relative proportion of the individual sterols among crude and refined vegetable oils was observed.
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- Analysis of free and esterified sterols in vegetable oils
Journal of the American Oil Chemists' Society
Volume 79, Issue 2 , pp 117-122
- Cover Date
- Print ISSN
- Online ISSN
- Additional Links
- esterified sterols
- free sterols
- gas chromatography
- vegetable oils
- Industry Sectors
- Author Affiliations
- 1. Faculty of Agricultural and Applied Biological Sciences, Department of Organic Chemistry, Coupure Links 653, 9000, Belgium
- 2. Department of Food Technology and Nutrition, 9000, Gent, Belgium
- 3. De Smet Engineering, Edegem, Belgium