Gas chromatographic analysis of plant sterols

Authors: Moser, Jill

Submitted to: Proceedings of the American Oil Chemists' Society
Publication Type: Book / Chapter
Publication Acceptance Date: 4/17/2011
Publication Date: 4/17/2011
Citation: Moser, J.K. 2011. Gas chromatographic analysis of plant sterols. American Oil Chemists' Society. Available: http://lipidlibrary.aocs.org/topics/phytosterols/index.htm.

Interpretive Summary:

Technical Abstract: Phytosterols are well-known for their ability to lower blood cholesterol by competing with absorption of cholesterol from the diet and reabsorption of bile cholesterol. Phytosterols as food ingredients are “Generally Recognized As Safe” (GRAS) by the FDA, and they are increasingly incorporated into various products as functional food ingredients. In the year 2000, the FDA approved a health claim relating phytosterol ester or phytostanol ester consumption to reduced risk for coronary heart disease, in foods such as margarines and spreads, salad dressings, snack bars, and dietary supplements. However, the FDA has recently proposed to extend the health claim to include free phytosterols and an increased number of conventional foods. The European Union (EU) has also approved similar health claims, and has established labeling guidelines for these foods. Labeling requirement by both the FDA and the EU include a declaration of the content of plant sterols or sterol esters, and include specifications for phytosterol or phytostanol composition of the esters. Thus, there is increased interest in qualitative and quantitative analysis of phytosterols in food products. Gas chromatography (GC) is the most common method for analyzing phytosterol content and composition. Phytosterol analysis employs three basic steps: (1) Sample preparation (sample weighing, lipid extraction (optional), addition of internal standard, acid and or alkaline hydrolysis, extraction of unsaponifiables, optional sample clean-up/further purification, (2) derivitization, and (3) GC analysis. These steps are described here in both an manner that is intended to be both informative and practical.