Purification of Ethyl Linoleate from Foxtail Millet (Setaria italica) Bran Oil via Urea Complexation and Molecular Distillation

Foxtail millet (Setaria italica) bran oil is rich in linoleic acid, which accounts for more than 60% of its lipids. Ethyl linoleate (ELA) is a commercially valuable compound with many positive health effects. Here, we optimized two ELA processing steps, urea complexation (UC) and molecular distillation (MD), using single-factor and response surface analyses. We aimed to obtain a highly concentrated ELA at levels that are permitted by current regulations. We identified the optimal conditions as follows: 95% ethanol-to-urea ratio = 15:1 (w/w), urea-to-fatty acid ratio = 2.5:1 (w/w), crystallization time = 15 h, and crystallization temperature = −6 °C. Under these optimal UC conditions, ELA concentration reached 45.06%. The optimal MD purification conditions were established as follows: distillation temperature = 145 °C and vacuum pressure = 1.0–5.0 × 10−2 mbar. Under these conditions, ELA purity increased to 60.45%. Together, UC and MD were effective in improving the total concentration of ELA in the final product. This work shows the best conditions for separating and purifying ELA from foxtail millet bran oil by UC and MD.

The Concentration of Polyunsaturated Fatty Acid in Palm Oil by Urea Complexation

<p>Linoleic acid is a Poly-Unsaturated Fatty Acid (PUFA) that corresponds to Omega 6 Fatty Acid. This is the major component of vegetable oil and very important for health. As an essential fatty acid, linoleic acid has to be obtained from foods. Consumption of omega fatty acid in the form of concentrate has more benefit than the whole oil. Fulfilling this requirement, effective method to separate PUFAs from vegetable oils is needed. One of the favorable methods is urea complexation. Palm oil was used as the fatty acids resource due to its potential feedstock in Indonesia. This aim of this research is to study the effect of urea, ethanol and free fatty acid (FFA) ratios during complexation of palm oil. This research was developed in three steps, 1) free fatty acid preparation from palm oil (saponification process), 2) crystallization of the fatty acids mixture and 3) filtration for separating the unsaturated fatty acid. Concentrated linoleic acid is obtained in the liquid phase, while the saturated fatty acid is obtained in the solid. This research resulted that the concentration of PUFA was increasing as the ratio of urea, FFA and ethanol increases.</p>