Separation Of Gamma Linolenic Acid Fromevening Primrose Oil With Urea Inclusion

Evening primrose oil from Oenothera biennis L.which has strong adaptability, is the only plant found much riched inγ-linolenic acid (GLA) so far, and the GLA not only has the strong biological activity, but also can be changed into two high-γ-linolenic acid (DGLA), then transformed into prostaglandin E1 (PGE1) and arachidonic acid (AA) to provide precursors for the formation of prostaglandins and biofilm, known as "the protagonist of functional foods in the 21st century." Seperating and purifying the GLA from evening primrose oil and giving it full play for medicinal and health value, have become the hotspot.In this thesis, evening primrose oil was the raw material, and urea adduction, widely applied at home and abroad, was adopted to isolate the high purity GLA. Through observing and analyzing the differences between the shape, aperture size and number of the Urea Inclusion Compound formed under different design process with microscope, and the composition of fatty acids before and after separation from evening primrose oil and urea inclusion compound by gas chromatography (GC), research results were as follows:1. The study of the forming process of urea inclusion compounds showed, except the inclusion time, effects of inclusion temperature, times and alcohol concentration on the formation of the urea inclusion compound were a little great; At the same time, the fast-cooling was superior to the slow- cooling, with the decreasing of inclusion temperature and increasing of inclusion times, the experimental results were better under 95 % ethanol. So it is feasible to reflect and guide the urea inclusion technology by observing the changing trend of the shape and amount of the crystal in the forming process of urea inclusion compound.2. The study on the effects of different technological parameters on the shape and number of the urea inclusion compound in the process confirmed once again that it did can offer reference to Urea inclusion process for further optimization from the point of crystallization, and explore a new way for the improvement of the process of the separation and purification of evening primrose oil. The single-factor tests showed that effects of alcohol concentration, ratio of raw materials, inclusion time,temperature and times on the urea inclusion compound were significant, and 95% ethanol was the most suitable for the urea inclusion. In addition, with the appropriate increase of ethanol and urea, the crystal was more complete, thicker and purer, the GLA purity higher. At the same time, with the extension of inclusion time, the decreasing of inclusion temperature and increasing of inclusion times, the urea inclusion compound became longer and thicker, which was favorable for the urea inclusion, and the optimal conditions of them were 36 h , -15℃, and 4 times, respectively. The results of the orthogonal test demonstrated that under the appropriate ratio and 95 % ethanol, the optimal combination was 60 h, -15℃and 3 times, which made the GLA purity reach 78.996 %.3. The results of the composition of fatty acids before and after separation from evening primrose oil and the urea inclusion compound which was detected by GC demonstrated that effects of different technological parameters on the purification of GLA from evening primrose oil were significant, which strongly confirmed once more that it was feasible and simple to optimize and guide the urea inclusion technology from the point of crystallization, and determined the best combination for the higher purity GLA: 95% ethanol, 1:2:6 ratio of raw materials, - 15℃, 60 h, 3 inclusion times.