Urea complexation for the rapid, ecologically responsible fractionation of fatty acids from seed oil

Urea complex formation is a classic method for fractionating fatty acids from seed and other oils. The method's simplicity, ease of scaling, and ecological friendliness suggest its reevaluation in regard to modern fractionation challenges. In keeping with this, a simple, quick, inexpensive, robust, and environmentally friendly procedure was developed for reducing the saturated free fatty acid (FFA) content of saponified low-erucic acid rapeseed oil (LEAR). The process involves formation of a homogeneous 65 degrees C solution of FFA and urea in 95% ethanol (5% water), followed by cooling of the resultant urea complex slurry to room temperature. The urea complex and liquid phases are separated by gravity filtration, and the urea isolated in each phase is removed by extraction with 60 degrees C water. Saturated LEAR oil FFA preferentially formed urea complexes easily separated from the noncomplexed, mostly unsaturated FFA, the main product of interest. The effects of single- vs, double-stage fractionations and several other variables (component mass or volume ratios, temperature, ethanol solvent to water ratio) were preliminarily evaluated. Results demonstrated the robustness, reproducibility, and simplicity of the method.