Analysis of sterol fractions from twenty vegetable oils

Abstract

Abstract The unsaponifiables separated from 20 vegetable oils were divided into sterol and three other (less polar compound, triterpene alcohol, and 4‐methylsterol) fractions by preparative thin layer chromatography. The amounts of the sterol fractions were more than ca. 30% in the unsaponifiables from all of the oils, except tohaku, pumpkin seed, and fagara seed oils. Composition of the sterol fractions were determined by gas liquid chromatography. Individual components of the sterol fractions were identified by gas liquid chromatography and combined gas liquid chromatography‐mass spectrometry. β‐Sitosterol was found as the most predominant component in the sterol fractions from all oils, except two, i.e. the sterol fraction from pumpkin seed oil contained no detectable amount of β‐sitosterol and the sterol fraction from akamegashiwa oil contained Δ 5 ‐avenasterol as the most abundant component. Campesterol, stigmasterol, Δ 5 ‐avenasterol, Δ 7 ‐stigmastenol, and Δ 7 ‐avenasterol and also trace amounts (at the very least) of cholesterol and brassicasterol were found in most of the oils analyzed. It may be noted that a large amount (ca. 9%) of cholesterol was detected in the sterol fraction from capsicum seed oil. The presence of 24‐methylenecholesterol and Δ 5 ‐avenasterol in the sterol fraction of akamegashiwa oil was demonstrated by isolation of these sterols.