Synthesis of mono- and diglycerides in water-in-oil microemulsions

Enzyme-catalyzed esterification was carried out in single-phase, oil-continuous microemulsions. The lipozyme was solubilized, along with glycerol and water, in the aqueous core of water/diethylhexyl sodium sulfosuccinate/hydrocarbon microemulsion system. Upon addition of fatty acid, mono- and diglycerides were formed, due to the esterification reaction taking place at the interface of the droplets in the microemulsion. The initial rate of conversion of oleic acid increases with oil chainlength of the continuous phase whereas final conversion is maximum for hexane. The conversion of stearic acid is 30% whereas conversion of oleic acid is 70%. The percent conversion of various fatty acids in the same continuous medium increases with fatty acid chainlength. The oleic acid/glycerol ratio is an important parameter for optimum conversion of oleic acid into glycerides. The yield can be increased by subsequent addition of glycerol after equilibrium is reached. High-performance liquid chromatography analysis of samples from microemulsions shows the presence of mono- and diglycerides. Possible mechanisms for the abovementioned effects are discussed.     

硼酸二甘油酯脂肪酸酯的合成研究

以硼酸、甘油为原料,在氮气保护下合成硼酸二甘油酯,然后在强酸性阳离子交换树脂催化下分别与月桂酸、肉豆蔻酸、硬脂酸反应合成出3种具有半极性键的有机硼酸酯表面活性剂.用红外光谱确定了产物的结构.研究了硼酸二甘油酯月桂酸酯的合成工艺,得到了优化的工艺条件,结果表明:硼酸与甘油的摩尔比为1∶2.0,反应温度为180 ℃,反应时间为4 h时,硼酸二甘油酯的收率为96.0%;硼酸二甘油酯与月桂酸的摩尔比为1∶0.9,反应温度为200 ℃,反应时间为3.5 h,催化剂用量(相对于月桂酸的质量)为2.0%时,月桂酸转化率为97.5%.硼酸二甘油酯肉豆蔻酸酯和硼酸二甘油酯硬脂酸酯在相同的工艺条件下合成时酸转化率分别为97.0%和96.4%.该工艺具有酸转化率高,后处理工艺简单的优点.     

延黄牛脂制备高纯度1,3-甘油二酯工艺

目的:提高延黄牛脂的附加值。方法:采用固定化脂肪酶Lipozyme RM IM为催化剂,牛油脂肪酸乙酯(乙醇解法自制)和甘油为原料制备1,3-甘油二酯,运用氢谱考察脂肪酶添加量、底物摩尔比、反应时间以及反应温度对粗反应混合物中1,3-甘油二酯含量的影响,并阐明醇解酯交换前后牛油与甘油二酯产物的脂肪酸组成变化。结果:1,3-甘油二酯合成最佳条件为脂肪酶Lipozyme RM IM质量分数为1%,底物摩尔比(n_{脂肪酸乙酯}∶n_甘油)2∶1,反应时间6 h,反应温度50℃。此条件下的1,3-甘油二酯生成率为72.5%,甘油酯得率为77%;纯化后纯度提高至90.79%。与原油(延黄牛脂)相比,甘油二酯产物中亚油酸和油酸含量分别升高了13.65%,6.47%,饱和度降低了7.17%。结论:延黄牛脂制备1,3-甘油二酯不仅能改变甘油酯结构,还可以改变牛脂的脂肪酸组成,降低其饱和度。     

Lipid cues for seed-carrying by ants inHepatica americana

We investigated the chemical basis for ants carrying the seeds ofHepatica americana, an ant-dispersed plant of eastern North America. A laboratory bioassay of seed and elaiosome extracts was based on the distance test items were carried byPogonomyrmex rugosus. Ants responded equally to isolated elaiosomes and to the diglyceride fraction. Diolein was a major component of the diglyceride fraction, which is consistent with a finding that 1,2-diolein releases seed-carrying byAphaenogaster rudis. Ants' response to the free fatty acid fraction was less intense. Gas chromatography of the fatty acid fraction indicated that oleic acid was a primary component, and oleic acid is known to elicit necrophoric behavior. No evidence supports an earlier suggestion that ricinoleic acid stimulates seed-carrying behavior. Ants failed to respond to seeds from which elaiosomes were removed.     

酶催化甘油解法制备甘油二酯马油工艺研究

优化酶催化甘油解法制备甘油二酯马油的工艺。以粗马油、甘油为原料,脂肪酶催化合成甘油二酯,采用单因素结合正交试验法,以甘油二酯含量为考察指标,对底物比(粗马油∶甘油)、反应温度、加酶量及反应时间等工艺进行优化,并用CS-9301薄层扫描仪,对甘油二酯进行定性定量检测。结果表明:甘油解法制备甘油二酯马油的最佳条件为粗马油∶甘油(1∶0.5),加酶量为每克粗马油400U脂肪酶,反应时间6h,反应温度40℃,所得甘油二酯马油中甘油二酯的含量达44.18%。     

一种新型的减肥食用油--二甘油酯及其生理功能

主要介绍了由天然脂肪酸与甘油合成得到一种合80％二甘油酯(DAG)的减肥食用油及其生理功能。该油中的DAG有70％为1，3—DAG，经消化后成1(或3)—单甘油酯，这种产物在小肠的黏液中难以重新合成三甘油酯(TAG)。且能增加肝脏内β—氧化酶的活性和氧的利用，从而长期摄入DAG油能防止肥胖症、高血脂、脂肪肝和糖尿病的产生。     

葵花籽油甘油二酯的制备及其在发酵乳应用中的特性研究

以葵花籽油为原料,通过酶法甘油解反应制备富含亚油酸的甘油二酯(DAG)。以乳脂DAG作对比,分析了葵花籽油DAG的主要脂肪酸组成,并作为脂肪替代物制备酸奶,测定了富含亚油酸DAG酸奶的流变特性和质构特性。结果表明,葵花籽油DAG最佳制备工艺条件为:甘油与葵花籽油质量比1∶10,脂肪酶添加量7. 13%,反应时间12. 35 h。在最佳条件下,葵花籽油DAG中DAG含量可达49. 21%,亚油酸含量为60. 17%。与乳脂DAG酸奶及乳脂酸奶相比,葵花籽油DAG酸奶体系的表观黏度较高、凝胶体系凝聚性更好,酸奶结构更稳定。     

酶法合成甘油二酯的研究进展

介绍了脂肪酶催化合成甘油二酯的工艺及其所用固定化酶反应器的研究进展。     

Temperature and concentration dependent effect of partial glycerides on milk fat crystallization

Two diglycerides (distearin and diolein) and two monoglycerides (monostearin and monoolein) were added to milk fat in a concentration of 0.5% and 1%. The isothermal crystallization behavior was evaluated at 22 °C, 23.5 °C, 25 °C and 26.5 °C by DSC and pNMR. The crystallization kinetic was quantified by means of two models. It was noticed that the effect of the minor components on the crystallization behavior depends on temperature and concentration. The type of esterified fatty acids and the polar head of the amphiphilic molecule determine to what extent partial glycerides influence the nucleation and crystal growth of triglycerides. Moreover the degree of insolubility of partial glycerides in the melt determines which effect (on growth or on nucleation) predominates. Stearic acid based partial glycerides enhance nucleation at low temperatures, while at higher temperatures an interaction with the crystal growth predominates. Oleic acid based partial glycerides have an effect on the nucleation process while no interaction with the crystal growth was observed.     

甘三酯立体专一分析的研究 Ⅲ.研究甘三酯“立体专一”分析方法应当注意的几个方面

在本论文第Ⅰ及第Ⅱ两部分基础上,本部分就有关各方法的比较、精密度、验证方法以及在色谱分离时的特殊问题等方面予以深入阐述。