Abstract
Change in compositions of 4, 4'-dimethylsterol in lipids of three oil seeds (sunflower, cotton and soybean seed) at different stages during maturation were investigated. The unsaponifiables in lipids from three oil seeds were separated into three fractions : 4-demethyl-, 4-monomethyl and 4, 4'-di-methylsterols by thin-layer chromatography. And the compositions of 4, 4'-dimethylsterols were analyz-ed by gas chromatography and gas chromatography-mass spectrometry.
The highest concentrations of unsaponifiables in lipids from three oil seeds were found at an early stage after flowering, but the contents then decreased steadily. The main components of 4, 4'-di-methylsterols in sunflower and cotton seed lipids were β-amyrin, cycloartenol and 24-methylenecycloartanol. The main components of 4, 4'-dimethylsterol in soybean seed lipids were β-amyrin, butyrospermol, cycloartenol, lupeol and 24-methylenecycloartanol. Generally, the percentage of β-amyrin in 4, 4'-dimethylsterols decreased up to maturity, but the percentages of cycloartenol and 24-methylenecyclo-artanol increased.
