Effect of genetic modification on the content and composition of bioactive constituents in soybean oil

The content and composition of tocopherols, sterols, and phospholipids in soybean oils derived from genetically-modified soybeans were determined by normal and reverse-phase high-performance liquid chromatography and gas-liquid chromatography. Tocopherol content was lowered in oils from soybeans selected to yield high palmitate and stearate contents. However, beta-tocopherol, which amounts to less than 1 ppm in control oils, was increased to 25-53 ppm in these oils. Sterol content was higher in one reduced-linolenate oil, which also had the highest oleate content. The greatest variability was observed in the content of beta-sitosterol, which ranged from 46.9-151.6 mg/100/g in the modified oils. Although, in general, there was little impact on the phospholipids, the content of phosphatidic acid was elevated in crude oils from three of the lines. Increases in phosphatidic acid are generally associated with storage deterioration of soybeans. Individual major classes of phospholipid were isolated, and the molecular species composition of each was determined. Compositional variations in molecular species indicated that there was an impact of the genetic modification of soybeans at the molecular level of the phospholipids that are primary plant cell components.