Fractionation of soybean phospholipids by high-performance liquid chromatography with an evaporative light-scattering detector

Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) from 23 soybean lines with a wide range of fatty acid compositions were resolved into seven fractions by high-performance liquid chromatography (HPLC). Fraction identities were assigned from fatty acid compositions determined by gas chromatography (GC). A mass detector, i.e., an evaporative light-scattering detector, was used for HPLC quantification. The detector response was a power function of PC and PE concentrations. Various correction methods were applied to the detector response to obtain the best agreement between phospholipid (PL) fatty acid compositions determined by GC and that calculated from the corrected HPLC fraction percentages. The corrected HPLC fraction composition also was compared with that calculated from stereospecific distribution data using a 1-random-2-random hypothesis. Correlation between PL-fatty acid and HPLC-fraction percentages showed that genetic modification of soybean oil composition caused changes in PL species, which alter physical properties and may alter the physiological functions of PL in biomembranes.     

Lipid composition ofCalophyllum inophyllum kernel

Total kernel lipids extracted fromCalophyllum inophyllum, Guttifereae amounted to 60.1% of the dry kernel. The total lipids consisted of 92.0% of neutral lipids, 6.4% glycolipids and 1.6% phospholipids. Neutral lipids consisted of triacylglycerols (82.3%), free fatty acids (7.4%) and small amounts of diacylglycerols, monoacylglycerols and sterols. At least four glycolipids and five phospholipids were identified. Acylmonogalactosyldiacylglycerol and monogalactosylmonoacylglycerol were major glycolipids; while monogalactosyldiacylglycerol and an acylated sterolglucoside were present in small amounts. The phospholipids consisted of phosphatidylethanolamine and phosphatidylcholine as major phospholipids, and minor amounts of phosphatidic acid, phosphatidylserine and lysophosphatidylcholine. The fatty acid composition of these different neutral lipids, glycolipids and phospholipids was determined.     

A simple and cost-effective gram-scale chromatographic method for the purification of soybean phospholipids

A method was developed for the preparative fractionation of soybean lecithin to enable the study of the functional properties of pure soybean phospholipids. Hereby, a coarse and irregularly shaped silica gel was used as the stationary phase, whereas the mobile phase consisted of three mixtures of hexane, 2-propanol, and water with increasing polarity. These solvents were included in a step gradient, which was formed by an isocratic pump connected to a solvent switcher. With this system, two grams of soybean lecithin were fractionated. The purity was evaluated by analytical high-performance liquid chromatography, and the recovery was estimated from concentration determinations by flow injection analysis. From these results, it was concluded that 60 to 75% of the three major soybean phospholipids could be recovered with a purity of at least 93%. Only 1.5 L of solvents were needed for both the column equilibration and the elution of all soybean phospholipids. Senior research associate of the Belgian National Fund for Scientific Research (N.F.W.O.).     

冷冻结晶法纯化制备高纯度磷脂酰乙醇胺

为解决工厂低磷脂酰胆碱（PC）含量大豆粉末磷脂的积压问题,以及获得高纯度的磷脂酰乙醇胺（PE）,以用碱性乙醇从低PC含量大豆粉末磷脂中提取的粗PE产品为原料,通过冷冻结晶法纯化制备高纯度PE。在单因素实验的基础上,以PE含量为指标,通过响应面实验对冷冻结晶纯化条件进行了优化。结果表明,PE的最佳冷冻结晶纯化条件为：料液比1∶40,冷冻时间21.5 h,冷冻温度-25℃,乙醇体积分数94%,乙醇碱浓度为94%乙醇与25%氨水体积比100∶8。在最佳条件下,产品PE含量为76.56%,PE回收率为81.25%。因此,冷冻结晶法纯化工艺可用于制备高纯度PE。     

A Simple Enzymatic Approach for Selective Acetylation of Phosphatidylethanolamine

Acetylation of lecithin improves the fluid properties, water dispersibility and emulsifying properties of a variety of food formulations. Acetylation of lecithin is usually carried out chemically using acetic anhydride in the presence of tertiary amine. In the present study acetylation of soybean lecithin and egg yolk lecithin was carried out using lipozyme IM 20 having 1,3-specificity from Mucor miehei and vinyl acetate at 70–75 °C. Vinyl acetate played a dual role as acetylating agent and also as the solvent medium. This method selectively acetylated phosphatidylethanolamine without effecting phosphatidylinositol since the enzyme employed was 1,3-specific.     

菜籽油脚中脑磷脂的提取与纯化工艺研究

以菜籽油脚为原料,采用溶剂分提法与柱色谱分离法相结合的工艺制备高纯度脑磷脂(PE).通过正交试验得出最佳的溶剂分提工艺参数为:分提时间20 min,粉末磷脂与95%乙醇溶剂比1:7,分提次数3次,分提温度40℃.在此条件下所得产物中PE含量为46.3%.采用硅胶为固定相的柱色谱分离技术对溶剂分提产物进行进一步纯化,试验结果表明:控制洗脱流速为3 mL/min,进样量为1.5 g(100 g硅胶),氯仿-甲醇(体积比2:1)为洗脱剂的条件下分离效果较好,所得PE产品的纯度为94.5%,回收率为85.1%.     

Symposium review: Milk fat globule size: Practical implications and metabolic regulation

Milk fat globule (MFG) size ranges over 3 orders of magnitude, from less than 200 nm to over 15 µm. The significance of MFG size derives from its tight association with its lipidome and proteome. More specifically, small MFG have relatively higher content of membrane compared with large globules, and this membrane exerts diverse positive health effects, as reported in human and animal studies. In addition, MFG size has industrial significance, as it affects the physicochemical and sensory characteristics of dairy products. Studies on the size regulation of MFG are scarce, mainly because various confounders indirectly affect MFG size. Because MFG size is determined before and during its secretion from mammary epithelial cells, studies on the size regulation of its precursors, the intracellular lipid droplets (LD), have been used as a proxy for understanding the mechanisms controlling MFG size. In this review, we provide evidence for 2 distinct mechanisms regulating LD size in mammary epithelial cells: co-regulation of fat content and triglyceride-synthesis capacity of the cells, and fusion between LD. The latter is controlled by the membrane's polar lipid composition and involves mitochondrial enzymes. Accordingly, this review also discusses MFG size regulation in the in vivo metabolic context, as MFG morphometric features are often modulated under conditions that involve animals' altered energy status.     

不同蜂花粉中磷脂成分的比较

采用薄层色谱、高效液相色谱分离测定蜂花粉中磷脂,并分析磷脂中不饱和脂肪酸的含量。结果表明：茶花、葵花、玫瑰、籽瓜、益母草蜂花粉中富含磷脂,其中茶花蜂花粉中总磷脂含量最高,主要由磷脂酰肌醇、磷脂酰丝氨酸、磷脂酰乙醇胺、磷脂酰胆碱及溶血卵磷脂组成;脂肪酸组成分析表明,蜂花粉中磷脂多不饱和脂肪酸含有较高含量的亚油酸和亚麻酸,5种蜂花粉磷脂中多不饱和脂肪酸含量均在50%以上,其中茶花蜂花粉磷脂中亚麻酸在脂肪酸含量中最高达56.0%。蜂花粉中多元不饱和磷脂具有广阔的开发前景。     

Biosynthesis of N-Docosahexanoylethanolamine from Unesterified Docosahexaenoic Acid and Docosahexaenoyl-Lysophosphatidylcholine in Neuronal Cells

We investigated the synthesis of N-docosahexaenoylethanolamine (synaptamide) in neuronal cells from unesterified docosahexaenoic acid (DHA) or DHA-lysophosphatidylcholine (DHA-lysoPC), the two major lipid forms that deliver DHA to the brain, in order to understand the formation of this neurotrophic and neuroprotective metabolite of DHA in the brain. Both substrates were taken up in Neuro2A cells and metabolized to N-docosahexaenoylphosphatidylethanolamine (NDoPE) and synaptamide in a time- and concentration-dependent manner, but unesterified DHA was 1.5 to 2.4 times more effective than DHA-lysoPC at equimolar concentrations. The plasmalogen NDoPE (pNDoPE) amounted more than 80% of NDoPE produced from DHA or DHA-lysoPC, with 16-carbon-pNDoPE being the most abundant species. Inhibition of N-acylphosphatidylethanolamine-phospholipase D (NAPE-PLD) by hexachlorophene or bithionol significantly decreased the synaptamide production, indicating that synaptamide synthesis is mediated at least in part via NDoPE hydrolysis. NDoPE formation occurred much more rapidly than synaptamide production, indicating a precursor–product relationship. Although NDoPE is an intermediate for synaptamide biosynthesis, only about 1% of newly synthesized NDoPE was converted to synaptamide, possibly suggesting additional biological function of NDoPE, particularly for pNDoPE, which is the major form of NDoPE produced.