The sterol fraction of coffee oil (Coffea arabica L.)

Abstract

The sterol composition of 20 samples of coffee seed oils from various origins, prepared by hexane extraction, was determined by GLC analysis of trimethyl silyl derivatives on a polar stationary phase (OV 17). The structural formulae of 23 unsaponifiables identified in coffee oil (pentacyclic diterpenes, triterpene hydrocarbons and alcohols, 4alpha-methyl sterols, and sterols inculding 5 and 7 sterols) are shown. Tabulated results from the 20 samples show the main components of the sterol fraction to be sitosterol (45.4-56.5%), stigmasterol (19.6-24.5%) and campesterol (14.8-18.7%), with smaller amounts of cholesterol (traces, i.e. <0.2% to 0.6%), 5 and 7-avenasterol (1.9-14.6% and traces-4.4% resp.) and 7-stigmasterol (0.6-6.6%).