Free and Esterified Sterol Distribution in Four Romanian Vegetable Oil

Abstract

The unsaponifiable lipid fraction of plant-based foods is a potential source of bioactive components such as phytosterols, triterpenoids, carotenoids, tocopherols and various hydrocarbons. The free and esterified sterol concentrations in four Romanian edible oils (corn germ, wheat germ, sweet almond and grape seed oil) were determined, including individual values for β-sitosterol, campesterol, stigmasterol, δ5-avenasterol, sitostanol, campestanol, and cholesterol. Free and esterified sterols were separated by solid-phase extraction (SPE), saponified, and analyzed as trimethylsilyl ether derivatives using gas-chromatography (GC) with flame ionization detector (FID). Differences in total sterol content and the proportion of esterified (ES) and free sterols (FS) were evident for studied oil samples. In general, β-sitosterol was the most prevalent phytosterol, ranging in concentration from 158.3 mg/100 g in grape seed oil to 478.5 mg/100 g in corn germ oil. Only in these two vegetable oil, we identified trace amount of cholesterol (