COMPOSITION AND DEVELOPMENT OF TURNIP RAPESEED (BRASSICA-CAMPESTRIS) OIL TRIACYLGLYCEROLS AT DIFFERENT STAGES OF MATURATION

Triacylglycerols (TAGs) were extracted with supercritical CO2 or diethyl ether from low erucic acid turnip rapeseeds harvested at various stages of maturity. The acyl carbon number (ACN) species of TAGs were quantified with supercritical fluid chromatography (SFC), and the fatty acids were analyzed as methyl esters with gas chromatography-mass spectrometry. The major acids of mature seeds were cis-9-octadecenoic (55%), cis,cis-9,12-octadecadienoic (22%), all-cis-9,12,15-octadecatrienoic (13%), n-hexadecanoic (3%), cis-11-octadecenoic (2.5%), n-octadecanoic (1.5%), eicosenoic (1%), n-eicosanoic (0.5%), cis-13-docosenoic (0.5%), and cis-15-tetracosenoic (0.5%) acids covering 99% of the TAG fatty acids. Proportions of the molecular weight species within the most abundant ACN fractions (ACN 54, 79%; ACN 52, 10%; ACN 56, 3%) were determined by ammonia chemical ionization mass spectrometry. The dominating double-bond species in ACN 54 varied between three and seven. Proportions of the 19 fatty acids and the 18 MW species analyzed remained fairly constant during the last 3 weeks of the growing season.