【作者】 杨琦；

【导师】 王华； 薛刚；

【作者基本信息】 西北农林科技大学 ， 食品科学， 2010， 硕士

【摘要】 月见草适应性强,其所榨月见草油是至今发现唯一含有大量γ-亚麻酸(GLA)的植物,且GLA不仅自身具有强大的生物活性,它还可以在体内转变成二高-γ-亚麻酸(DGLA),进而转变为前列腺素E1(PGE1)和花生四烯酸(AA),为前列腺素及生物膜的构成提供前体,被誉为“21世纪功能性食品的主角”。分离纯化月见草油中GLA,充分发挥月见草油中GLA的药用和保健价值,已成为当今研究热点。本论文以月见草油为原料,采用目前国内外普遍适用的尿素包合法分离出较高纯度的GLA,通过显微镜对不同设计条件下包合过程及其析晶过程中形成的包合物形态、直径大小及数量多少差异的观察分析,利用气相色谱(GC)对月见草油被包合分离前后及包合物中提取油脂的脂肪酸组成变化分析,得到如下研究成果:1、尿素包合结晶物的析晶过程研究表明:包合温度、包合次数及酒精浓度对包合物的析晶影响较大,而包合时间并非主要影响因素。快速降温优于缓慢降温,随包合温度降低、包合次数增加,使用95 %乙醇时,包合效果相对越好。通过观察析晶过程中包合物形态及量变趋势,来反映并指导包合工艺是可行的。2、尿素包合过程中不同工艺参数对包合物形态及数量的影响研究再次证实,从结晶物角度为进一步指导优化包合工艺提供参考,在月见草油分离纯化的工艺改进领域探索了一条新途径。单因素试验表明:乙醇浓度、原料配比、包合时间、包合温度及包合次数对尿素包合物的影响均为显著,95 %乙醇最适于尿素包合,且随乙醇和尿素量适宜增加,结晶物完整、粗大而纯净,GLA纯度相应越高;同时包合时间延长、包合温度降低、包合次数增加,形成结晶物越长越粗,有利于尿素包合,其最佳工艺点依次为36 h、-15℃、4次;正交试验表明:适宜配比的95 %乙醇浓度下,-15℃、60 h、包合3次为最佳工艺,该条件下GLA纯度达78.9964 %。3、采用GC检测了月见草油被尿素包合分离前后及包合物中脂肪酸的组成,结果显示:不同包合工艺参数对纯化月见草油中GLA工艺的影响均为显著,再次有力地证实了由结晶物角度来优化指导包合工艺是可行而便捷的,且确定了较高纯度GLA获得的最佳工艺组合为:95 %乙醇浓度、1:2:6原料配比、-15℃、60 h、包合3次。更多还原

【Abstract】 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.更多还原