Phytosterols and phytostanols in palm oils

الملخص EN

Background and objectives Phytosterols (plant sterols) are triterpenes that are important structural components of plant membranes.

They serve to stabilize phospholipid bilayers in plant cell membranes just as cholesterol does in animal cell membranes.

Phytostanols occur in trace levels in many plant species and they occur in high levels in tissues of only in a few cereal species.

In this study the search was mainly for sitostanol which reduces cholesterol absorption in the bowel.

In addition to other unidentified plant sterols in the crude palm oil (CPO), crude palm kernel oil (CPKO) and crude palm fiber oil (CPFO) extracts.

Methods The unsaponifiable sterols extracts from CPO, CPKO and CPFO were isolated by preparative thin layer chromatography.

The isolated sterols were analysed as free and trimethylsilylated (TMS) derivatives by GC correlations and GC-MS mass spectral data in comparison with their standard sterols.

Results Qualitative and quantitative separations of the sterols are illustrated.

Tables are presented showing the sterols composition determined in the oils.

There were no major differences between the above three oils with respect to their main sterols composition, but the total amount of the sterols in CPFO were much higher than CPKO and CPO respectively.

In addition to the well identified sterols in the palm oils (i.e cholesterol, campesterol, stigmasterol and β-sitosterol).

Additional sterols were isolated and identified in CPO: stellasterol and cycloartenol.

CPKO: fucosterol, 5α-4,4-dimethylcholest-8,24-dien-3β-ol and cycloartenol, CPFO: brassicasterol, sitostanol and 4,4-dimethylcholest-5-en-3β-ol.

Conclusions Sitostanol was only found in CPFO (16 ppm) but was not found in CPO or CPKO.