VARIATION IN LIPID-COMPOSITION OF NIGER SEED (GUIZOTIA-ABYSSINICA CASS) SAMPLES COLLECTED FROM DIFFERENT REGIONS IN ETHIOPIA

Niger seed samples were collected from different regions in Ethiopia f or determination of oil content, and of fatty acid, tocopherol and ste rol composition in the seed oil by gas-liquid chromatography and high- performance liquid chromatography methods. There was a large variation in oil content, ranging from 29 to 39%. More than 70% of the fatty ac ids was linoleic acid (18:2) in all samples analyzed. The other predom inant fatty acids were palmitic (16:0), stearic (18:0) and oleic (18:1 ) at a range of 6 to 11% each. Total polar lipids recovered after prep arative thin-layer chromatography comprised a small fraction of the to tal lipids. They had higher 16:0 and lower 18:2 contents than the tria cylglycerols. alpha-Tocopherol was the predominant tocopherol in all s amples, 94-96% of the total amounting to 630-800 mu g/g oil. More than 40% of the total sterols was beta-sitosterol, ca. 2000 mu g/g oil. Th e other major sterols were campesterol and stigmasterol, ranging from 11 to 14%. The Delta 5- and Delta 7-avenasterols were in the range of 4 to 7%. From the samples studied, no conclusion could be drawn regard ing the influence of altitude or location on oil content, tocopherol a nd/or sterol contents. The results of the present study on niger seed oil are discussed in comparison with known data for common oils from C ompositae, viz, safflower and sunflower.