ABSTRACT
Foods fortified with phytosterols are complex samples containing a wide variety of compounds or compound classes present at widely differing concentration levels. In a typical PS containing vegetable oil-based spread for example, tri-acylglycerides can be present at levels as high as 60%. On the other hand, vitamins will generally not exceed the microgram to milligram/100g product (ppb to ppm range). The applicability of gas chromatography for rapid profiling of the main compound groups in the fat fraction of a spread sample is illustrated in Fig. 14. This figure shows the analysis of a sample containing free sterols, sterol esters, free fatty acids (FFAs), monoacylglycerides (MAGs), diacylglycerides (DAGs), and triacylglycerides (TAGs). The derivatized compounds are separated on an apolar capillary column according to their boiling points, which correlate closely with the CN of the respective molecules. The chromatographic method used is the so-called carbon number method and is currently being reviewed for publication as an ISO standard method (36). Free fatty acids, free and esterified sterols, as well as acylglycerides can easily be detected and elute in clearly identifiable component groups. For PSs esterified with fatty acids covering a limited carbon number range, such as is the case for fatty acids derived from sunflower oil, no overlap in any of the component groups
