Phytosterol accumulation in canola, sunflower, and soybean oils: Effects of genetics, planting location, and temperature
To assess the potential of traditional selection breeding to develop varieties with increased phytosterol content, we determined concentrations of those sterols in canola, sunflower, and soybean seed oils produced from breeding lines of diverse genetic backgrounds. Seed oils were extracted and saponified, and the nonsaponifiable fractions were subjected to silylation. The major phytosterols brassicasterol, campesterol, stigmasterol and β-sitosterol, were quantified by capillary gas chromatography with flame-ionization detection. Canola contained approximately twice the amount of total phytosterols (4590–8070 μg g−1) as sunflower (2100–4540 μg g−1) or soybean (2340–4660 μg g−1) oils. Phytosterol composition varied among crops as expected, as well as within a crop. Both genetic background and planting location significantly affected total phytosterol concentrations. Soybean plants were maintained from flower initiation to seed maturity under three temperature regimes in growth chambers to determine the effect of temperature during this period on seed oil phytosterol levels. A 2.5-fold variability in total phytosterol content was measured in these oils (3210–7920 μg g−1). Total phytosterol levels increased with higher temperatures. Composition also changed, with greater percent campesterol and lower percent stigmasterol and β-sitosterol at higher temperatures. In these soybean oils, total phytosterol accumulation was correlated inversely with total tocopherol levels. Owing to the relatively limited variability in phytosterol levels in seed oils produced under field conditions, it is unlikely that a traditional breeding approach would lead to a dramatic increase in phytosterol content or modified phytosterol composition.
Key WordsCariola oil fatty acid composition genetic modification phytosterols planting location soybean oil sunflower oil temperature tocopherols
Unable to display preview. Download preview PDF.
- 2.Clark, J., Tocopherols and Sterols from Soybeams, Lipid Technol. 8:111–114 (Sept. 1996).Google Scholar
- 3.Mounts, T., S. Abidi, and K. Rennick, Effect of Genetic Modification on the Content and Composition of Bioactive Constituents in Soybean Oil, J. Am. Oil Chem. Soc. 73:581–586 (1996).Google Scholar
- 4.Dolde, D., C. Vlahakis, and J. Hazebroek, Tocopherols in Breeding Lines and Effects of Planting Location, Fatty Acid Composition, and Temperature During Development Ibid. 76:349–355 (1999).Google Scholar
- 5.Analysis of Oilseeds, Fats and Fatty Foods, edited by J. Rossell and J. Pritchard, Elsevier Applied Science, London, 1990, pp. 315, 317.Google Scholar
- 6.Gordon, M., and L. Miller, Development of Steryl Ester Analysis for the Detection of Admixtures of Vegetable Oils, J. Am. Oil Chem. Soc. 74:505–510 (1997).Google Scholar
- 7.The Lipid Handbook, edited by F. Gunstone, J. Harwood, and F. Padley, Chapman & Hall, London, 1994, p. 128.Google Scholar
- 11.Palta, J., B. Whitaker, and L. Weiss, Plasma Membrane Lipids Associated with Genetic Variability in Freezing Tolerance and Cold Acclimation of Solanum Species, Plant Physiol. 103:793–803 (1993).Google Scholar
- 15.Whitaker, B., Lipid Changes in Mature-Green Tomatoes During Ripening, During Chilling, and After Rewarming Subsequent to Chilling, J. Am. Soc. Hort. Sci. 119:994–999 (1994).Google Scholar
- 18.Guye, M., Sterol Composition in Relation to Chill-Sensitivity in Phaseolus spp, J. Exp. Bot. 39:1091–1096 (1998).Google Scholar
- 20.Fernadez, P., and S. Juan, Study of High Oleic Sunflower Oils, Fatty Acid Composition, Alimentaria 243:63–66 (1993).Google Scholar