Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 3, 2003
Publication Date: October 7, 2003
Citation: Moreau, R. A., Powell, M. J. and Hicks, K.B., 2003. Evaluation of a commercial enzyme-based serum cholesterol test kit for the analysis of phytosterol and phytostanol products. Journal of Agriculture Food Chemistry 51:6663-6667. Interpretive Summary: Several phytosterol-enriched functional food products have been commercialized in recent years. The first of these products were margarines, but phytosterols are now being incorporated into many other types of foods. Currently, the only way to measure phytosterols in these types of foods is to use an expensive instrument such as gas chromatograph or high performance liquid chromatograph. Simpler methods are available to measure cholesterol in blood samples and in this study we evaluated one of these methods as an alternative to measure phytosterols. The results indicated that phytosterols could be measured if the incubation time of the method was extended from 5 minutes to 60 minutes. Although this modified method is probably not sensitive enough to measure the natural levels of phytosterols in most fruits and vegetables, the method should be useful to measure phytosterols in various types of foods that have been fortified to a level of 5-10% in phytosterols.
Technical Abstract: Plant sterols (phytosterols) have been shown to possess serum cholesterol-lowering properties. In recent years several phytosterol-enriched functional food products have been developed. Some phytosterol products contain common unsaturated sterols and some contain a subset of phytosterols called phytostanols (saturated sterols, also called plant stanols). Current methods for the quantitative analysis of plant sterols are labor intensive and require sophisticated gas or liquid chromatographs. In this study, a popular spectrophotometric serum cholesterol test kit was evaluated for the analysis of plant sterols. The results indicate that the method could be modified to analyze phytosterols and phytostanols by increasing the incubation time. Both free phytosterols and fatty acyl phytosteryl esters were quantitatively analyzed but ferulate phytosteryl esters, which occur in corn and other cereals, were not hydrolyzed or analyzed.