Natural Sources of Dietary Plant Sterols

In this study, plant sterol contents in the most important oils and margarines and cereal products, as well as in vegetables, fruits and berries, available in Finland were determined. The samples were purchased from retail stores or market places or directly obtained from the food industry. Sterols in oils and margarines were analysed by capillary gas chromatography after sample preparation including alkaline hydrolysis to liberate sterols from their esters. Sterols in more complex samples were determined by using a method that comprised of acid hydrolysis prior to alkaline hydrolysis in order to include steryl glycosides in the total sterol yield. Among the oils analysed, rapeseed and maize oils were especially rich in sterols. In Finland, rapeseed oil is the most important oil in margarine production resulting in high sterol contents in margarines. Sterol contents in cereal products correlate with their ash contents. Thus, whole grain flours and especially bran fractions were better sources of plant sterols than refined flours. Many vegetables, fruits and berries have substantially high sterol contents on a dry weight basis. However, they are only moderately important sources of sterols on a fresh weight basis.