Study On Separation And Purification Of Polyunsaturated Fatty Acids From Alga Oil

Taking docosapentaenoic acid(DPA) and docosahexaenoic acid(DHA) as representation,ω-3 polyunsaturated fatty acids(PUFA) and their derivatives have lots of physiological functions, such as promotion of the growth of babies and children's brains and eyes, enhancing the immunity, reducing the risk of blood-lipid, preventing of heart disease and so on. It has become to be the hot point of research. But there are many defects in currently methods, which sourced PUFA from fish oil or seal oil. Some researcher has begun to study the technology of separation and purification of PUFA from alga oil. In this paper, the separation and purification of PUFA from alga oil by urea inclusion fractionation and liquid chromatography was studied. It is also reported that a process for high pured DPA ester and DHA ester and relative problems. The results are valuable for the deep processing of alga oil and the development of PUFA series for the manufacture of food and medicine.It is also established that an analysis method for PUFA by gas chromatography. The qualitative and quantitative analyses are available for PUFA fast and accurately. The physiochemical properties of alga oil were analyzed. The method and the data support the research on separation of PUFA and their derivatives.It was discussed that the factors which influent the separation effect, including the tatio of solvent and fatty acid, the ratio of urea and PUFA, the crystal temperature and crystal temperature time. Based on the results, orthogonal experiment was used to optimize the separation process by the target of the purity and recovery of DPA and DHA relatively. The result showed that the purity of DPA and DHA reached 26.94% and 69.75%, and the recovery of DPA and DHA reached 81.19% and 89.53% relatively when the ratio of solvent and fatty acid is 6:1, the ratio of urea and PUFA is 1:1, the temperature is -5℃.The production of PUFA by urea inclusion was methylated and the fatty acid became methyl PUFA mainly including methyl DPA and methyl DHA. The preparative liquid chromatography was used to divide the two components, and methyl DPA and methyl DHA of up to 96% purity can be relatively recovered finally. The report discussed the influences of some factors including different kind of stationary phrase, the temperature and the volume of sample for recovery and separation effect. The result showed that the optimal effect would be available when used the AgNO3-silica gel as stationary phrase under 20℃, and the ratio of sample and stationary phrase should be 5% (w/w). The magnified experiment was carried out following these factors. The mechanism of absorption of methyl PUFA and AgNO3-silica gel and other phenomena in the purification process were also discussed.