Dairy Lecithin from Cheese Whey Fat Globule Membrane: Its Extraction, Composition, Oxidative Stability, and Emulsifying Properties

An ethanol extraction method was studied for the production of dairy lecithin from cheese whey-derived milk fat globule membrane (MFGM). A two-step ethanol extraction of MFGM involving first extraction at pH 6.5, followed by second extraction at pH 4.5 yielded 17.2 % lipids. The extracted material contained about 90 % lipids, 4.5 % ash, and 1.2 % moisture. The phospholipid content of the ethanol extract was 31 % and the remainder was mostly neutral lipids. The phospholipid fraction contained 34 % sphingomyelin, 31 % phosphatidylcholine, 27 % phosphatidylethanolamine, 4.6 % phosphatidylserine, and 3.1 % phosphatidylinositol. Since the ethanol extract contained 31 % phospholipids, it can be technically termed as dairy lecithin. The major fatty acid components were linoleic acid (5.1 %), myristic acid (8.3 %), palmitic acid (29 %), stearic acid (14 %), oleic acid (25 %), and the remainder was minor fatty acids with chain length ranging from C4:0 to C22:5. The dairy lecithin was semi-solid at room temperature and exhibited a major phase transition at about 35 °C. Owing to its low polyunsaturated fatty acid content, the dairy lecithin was reasonably stable to oxidation as measured by the rate and extent of hexanal production during 35 days of storage at 45 °C. Oil-in-water emulsions made with less than 2 % dairy lecithin (relative to the total emulsion weight) were unstable; however, emulsions made with greater than 4 % dairy lecithin were very stable for more than 60 days at room temperature. The results of this study indicated that a highly functional dairy lecithin can be commercially produced using cheese whey-derived MFGM as the starting material.     

Perstraction of Phenolic Compounds from Aqueous Solution Using a Nonporous Membrane

Abstract

An exploratory study of nondispersive extraction of various phenolic solutes using a nonporous membrane has been carried out. Sorption and permeation data for these solutes have been obtained using a silicone rubber membrane. The effects of hydrodynamic factors, concentration of phenols, and temperature on the trans-membrane flux are discussed. A film model is used to determine the intrinsic mass transfer characteristics of the membrane. Comparison of sorption of phenolic solutes from the membrane into the organic solvent indicates that methyl isobutyl ketone is a better solvent than butyl acetate.     

Simple and Efficient Profiling of Phospholipids in Phospholipase D-modified Soy Lecithin by HPLC with Charged Aerosol Detection

Dietary phosphatidylinositol (PI) can be synthesized via phospholipase D (PLD)-catalyzed transphosphatidylation of phosphatidylcholine (PC), abundant in soy lecithin, with myo-inositol. However, a generated mixture of phospholipid (PL) classes poses a challenge for analysis. Our current work on Streptomyces PLD engineering requires a robust analytical method for profiling of PI and related PLs derived from the transphosphatidylation reactions. Therefore, we optimized an HPLC-based method with charged aerosol detector (CAD) for PL quantification. PLs were separated on a normal phase silica column by a gradient elution system using two solvents containing chloroform/methanol/1 M formic acid–triethylamine buffer in different ratios. Retention times of the PL standards and LC–MS under identical conditions were used to identity PL classes. PL standards gave linear response in 100- and 10-fold (lyso-PI) concentration range. The method provided a simple, sensitive, repeatable, and precise analysis of PI, PC, phosphatidylethanolamine, phosphatidic acid, and lyso forms of PC and PI. Compared to the similar existing method, introduction of CAD provided a three- to fivefold decrease at the lower end and a two- to fivefold increase at the upper end of the dynamic range. High precision, high sensitivity, and low limits of detection and quantification further underline the benefits of CAD in PL analysis.     

Krill Lecithin as Surfactant for Preparation of Oil/Water Nanoemulsions as Curcumin Carriers

Curcumin is a component in Curcuma longa L. with documented bioactive properties but has low bioavailability. To overcome this problem, curcumin nanoemulsions are prepared employing omega-3-rich phospholipids from krill oil as a surfactant and serve as curcumin carrying systems. The phospholipids are obtained through aqueous (LAD) and ethanolic (LED) degumming processes. The data obtained shows that LAD has a recovery of 70.7 ± 0.51% (w/w) phospholipids, being more efficient than LED with 45.97 ± 1.27% (w/w). Also, a higher content of omega-3 fatty acids is found in LAD with 36 ± 2.14% (w/w). From the critical micellar concentration (CMC) as an assessment of emulsifying capability, it is found that the krill oil (KO), LAD, and LED has a CMC in the range 0.666–0.700 g L⁻¹. Two formulations with different surfactant levels are developed: experiment A with 9.5% and experiment B with 4.75% (w/w) of krill lecithin are obtained by aqueous degumming. In the formulation of nanoemulsions average particle sizes of 139 ± 2.5 and 142 ± 5.3 nm are produced for experiments A and B, respectively. These results indicate that krill lecithin is an omega-3 rich good surfactant which can be employed to encapsulate curcumin. Practical applications: An interest has emerged in the food industry to develop surfactants with nutritional value. Phospholipids are natural emulsifiers that are widely used to form nanoemulsions because of their elevated interfacial activity. Krill oil has been reported to be an important source of phospholipids and omega-3 fatty acids, which are mainly esterified to phospholipid moieties. Because of these properties, krill oil phospholipids could form micelles and function as carrier systems for bioactive compounds, thus increasing their permeability in the intestine. Consequently, the present work focused on obtaining a nanostructure using a natural surfactant that possesses fatty acids with nutritional value such as omega-3 fatty acids. This will provide an added value to the product obtained, as well as improve the bioavailability of non-polar bioactive compounds. The results obtained could justify the use of krill oil as a useful functional food additive.     

新疆胡麻卵磷脂制片初步研究简

文章以新疆胡麻卵磷脂为主料,淀粉、羟丙基纤维素、硫酸钙等为辅料,采用湿法制粒,制各了卵磷脂片剂.从设计的四种配方中,筛选出了最佳方案,并针对卵磷脂制片中辅料用量、片剂成型等影响因素进行了分析和评价.     

大豆卵磷脂的提纯与磷脂酰胆碱含量的分析

全溶剂法从大豆浓缩磷脂中提取卵磷脂,采用丙酮脱油、乙醇溶解、三氧化二铝脱色的工序,着重考察了丙酮的脱油条件对丙酮不溶物和卵磷脂收率的影响,最佳脱油条件:水浴温度45°C为宜,脱油时间60 min,丙酮用量150 mL,脱油次数3次。采用高效液相色谱分析磷脂酰胆碱的含量,结果表明,采用甲醇/乙腈/水为流动相可以分析磷脂酰胆碱的含量,并且稳定性和重现性都比较好。     

世界卵磷脂(PC)纯化工艺研究概况

概述了近年来世界有关制备高纯卵磷脂的研究成果和纯化工艺的研究进展,对五大类制备高纯卵磷脂的方法进行了简要介绍了评述.     

陶瓷膜净化溶剂油的实验研究

研究了平均孔径0.2 mm的陶瓷膜对含杂质溶剂油的微滤过程,选用不加水和加0.5%(w)水2种料液,考察了操作时间、跨膜压差、错流速度、温度和铝粉含量对膜通量及铝粉截留率的影响,研究了反冲操作、浓缩和污染膜清洗过程. 结果表明,不加水较加水料液的膜通量明显增大;随操作时间延长,膜通量下降至稳定,铝粉截留率迅速增大至100%;跨膜压差增大或温度升高使稳定通量增大;错流速度增大,稳定通量先升高之后不变;铝粉含量越高,膜通量越低. 适宜的操作参数为跨膜压差0.16 MPa、错流流速3.9 m/s和温度40℃. 反冲操作能有效提高膜通量;浓缩过程中膜通量快速下降至平缓阶段再较快降低,净化溶剂油澄清透明;采用0.15%(w)洗洁精和0.25%(w)硝酸清洗可使通量恢复到新膜通量的94.9%.     

Experimental Study of the Effect of Membrane Porosity on Membrane Absorption Process

Abstract

Five kinds of expanded polytetrafluoroethylene (ePTFE) flat membranes with different porosity and micro‐pore size were chosen to carry out the unsteady state gas absorption experiments. The influence of the membrane porosity and micro‐pore size on the membrane absorption process was investigated. Experimental results showed that the membrane porosity had an impact on the membrane absorption process, and the degree of this impact depended on the absorption system and the membrane pore size. For a rapid mass transfer process, the porosity affected the mass transfer more significantly, while for the slow mass transfer process the porosity almost did not affect the mass transfer. The modeling analysis showed that the porosity affected the concentration profile of the solute near the membrane surface on the liquid side, which led to the reduction of the mass transfer area of the membrane. Hence, the apparent effect on the mass transfer of the membrane absorption process.     

Degumming,Dewaxing and Deacidification of Rice Bran Oil-Hexane Miscella Using Ceramic Membrane: Pilot Plant Study

An indigenously developed low-cost clay-alumina-based ceramic microfiltration membrane of 19-channel configuration has been evaluated for degumming, dewaxing and deacidification of rice bran oil (RBO) miscella having different oil contents at pilot scale. Rice bran wax and soap particles in miscella will aggregate with changes in temperature. This suggests a technique for their effective separation. Low-temperature cross-flow membrane filtration was used for single-stage degumming-dewaxing and showed 70 % and 80 % removal of acetone insoluble residue from two RBO miscella samples, respectively. Color reduction was 50 %, and oryzanol retention was 70 %. NaOH was used for deacidification in a 10 % excess of that required based on the free fatty acid content in oil. This reduced free fatty acids to 0.2 %. Operating for 10 h with a 0.7 bar trans-membrane pressure, permeate fluxes of 15 and 8 L/m² hr were obtained for the degumming-dewaxing and deacidification operations, respectively. The process has advantages, such as high micronutrient content (1.56 % oryzanol) and negligible oil loss (2.6 %). Moreover, ceramic membrane processing of RBO miscella could be an effective pre-treatment step with respect to micronutrient enrichment, elimination of heating, neutral oil recovery and a viable option for solvent separation.     

微孔膜制乳技术基本规律研究

在对制乳技术进行充分调研的基础上 ,选择水 -正丁醇和水 -煤油为实验体系 ,以十二烷基磺酸钠、Span85等表面活性剂为乳化剂。在 0 .2 μm的陶瓷膜中研究了压力、连续相流量等因素对乳液粒径大小、分布和分散相通量的影响。实验结果表明 ,用微孔膜可以制得分布均匀的乳状液。乳化剂的类型与用量对乳液的性质有显著影响。微孔膜对低界面张力及界面张力中等的体系可制得粒径小、分布窄的O/W乳液。连续相流量和膜两侧压差对于乳液粒径和粒径分布没有明显的影响 ;分散相通量随压差的增大而明显增大 ,但连续相流速对分散相通量影响不大。     

利用膜分离技术回收正丁醇/水混合液的工艺研究

研究了聚乙烯醇（PVA）／聚丙烯腈（PAN）、海藻酸钠（SA）／PAN复合膜及海藻酸钠／醋酸纤维素（CA）共混膜等五种膜的渗透汽化特性,发现它们对正丁醇／水的混合液均表现为水优先透过,其渗透通量与选择分离系数都很高。并初步确定了正丁醇／水混合液渗透汽化分离的工业生产操作条件。     

膜技术在放射性废水处理中的应用研究

放射性废水传统的处理方法主要包括过滤法、蒸发法、离子交换法或这几种工艺的组合。近年来,膜分离技术作为一项新兴的高效分离浓缩技术,分离纯化性能较好,能够广泛应用于放射性废水的处理工艺中。本文介绍了各种膜处理技术,以及膜技术在放射性废水处理中的应用进展,并提出了膜技术应用尚需进一步研究和开发的具体方向。以期为我国放射性废水的处理技术发展提供借鉴和参考。     

聚偏氟乙烯平板膜处理MgCl2水溶液的实验研究

采用聚偏氟乙烯平板膜,研究MgCl2水溶液在40g／L时减压膜蒸馏性能。实验结果表明,随着温度的升高,膜的渗透通量明显增大,通量随着膜后真空侧的压力增大而减小。聚偏氟乙烯平板膜表现了很好的疏水性,MgC2。水溶液的截留率在99．9％以上。     

膜浓缩木醋液的工艺研究

综合利用超滤、纳滤和反渗透膜分离技术,对商丘三利新能源有限公司的粗制木醋液进行了浓缩处理。实验结果表明,在处理量为300L/h的条件下,原液中的总有机酸回收率可以达到90%以上,乙酸的回收率超过85%,同时木醋液经单套膜组件处理后含水量减少45%。     

反胶团法制备氧化钛超滤膜的研究

采用新型的反胶团法制备了氧化钛超滤膜。实验以钛酸丁脂、水、环己烷、异戊醇及表面活性剂Span-80等为原料,通过控制水量制得三种粒径分布的氧化钛反胶团微乳液。TEM照片表明,TiO2反胶团粒子随着[H2O]/[Span-80]由13.9增加到55.5而增大,但当[H2O]/[Span-80]增加到110.9时TiO2反胶团粒子反而减小。BET法结果与TEM照片一致,而且表明[H2O]/[Span-80]为110.9的TiO2反胶团微乳液所制得的无支撑膜孔径分布最窄、最可几孔径约为4.5nm。采用该种微乳液所制得的氧化钛支撑膜的最可几孔径约为16nm, 纯水渗透率为1.57×10-4m3(m2sMPa)-1;常温下N2、H2渗透率分别为4.3mol (m2sMPa)-1和14.1mol(m2sMPa)-1,表明所得TiO2分离层较完整。     

Effect of the full refining process on rice bran oil composition and its heat stability

The effects of the chemical refining process on the minor compounds of rice bran oil and its heat stability were investigated. After 8 h of heating, about 50% and 30% of total tocopherols remained in crude and refined rice bran oil, respectively. The individual tocopherols were differently affected by the refining process. The order of heat stability of tocopherols and tocotrienols in crude oil was found to be different from that in fully refined oil. A similar tendency was observed for sterols. After 8 h of heating, 65% and 72% of total sterols, and 14% and 46% of sterol esters, of crude or fully refined rice bran oil, respectively, disappeared. The heating process led to a 4% and 10.3% increase in polymer contents in crude and refined rice bran oil, respectively. Although refined rice bran oil showed good heat stability, when compared to crude oil its heat stability was decreased to some extent.     

Effects of Oleic Acid and Phospholipids on the Formation of Lecithin Organogel and Microemulsion

The formation of organogels and microemulsions of lecithin in the presence of a biocompatible cosurfactant, oleic acid, was studied. Low content of oleic acid ([oleic acid]/[lecithin] < 0.1) in the lecithin–oleic acid–dodecane–water system leads to an expansion of the region of existence and to a decrease in the viscosity of lecithin organogels. At high contents of oleic acid ([oleic acid]/[lecithin] > 0.6), low‐viscosity microemulsion exists in the system. Phosphatidylethanolamine, lysophosphatidylcholine, and other phospholipids that are present as impurities in the commercial samples of soybean lecithin can act as cosurfactants. For the first time, the formation of lecithin organogels in the systems containing commercial samples of soybean lecithin with phosphatidylcholine concentrations of 69.3 wt% (Lipoid S75) and 52.9 wt% (Lipoid S45) and saturated aliphatic hydrocarbons is demonstrated. The gelation is observed at T =25 °C in octane, decane, dodecane, and hexadecane for Lipoid S75 and in dodecane and hexadecane for Lipoid S45. A decrease in the degree of purification of lecithin leads to an expansion of the regions of existence of the organogels and to a reduction of their viscosity.     

溶胶凝胶法氧化铝分离膜制备工艺探讨

以异丙醇铝为主要原料,将原料予处理后,用溶胶-凝胶法制备Al2O3膜,考察胶溶剂的种类和用量、水解温度、回流时间等制备条件对Al2O3膜微观结构的影响.研究结果表明,选择用HCl作为胶溶剂,调节溶液pH值为2.0～3.5、水与乙醇体积量比为1∶1、水解温度为80～85 ℃左右.通过预处理,合成时间缩短,为6～8 h左右.可以制得微观结构性能比较好的Al2O3膜.     

静电自组装质子交换膜燃料电池用膜电极的光谱学分析

合成了一种季铵聚阳离子(PDDA)修饰的纳米Pt颗粒,采用静电自组装的方法将这种颗粒组装到质子交换膜(PEM,Nafion112)表面,Pt粒子的表面原子状态、Pt的还原和自组装过程以及自组装膜的电化学性能分别采用傅里叶转换红外(FTIR)、紫外-可见吸收光谱(UV-vis)和电化学工作站分析。结果表明,较低的修饰离子含量有利于提高还原速度和增加Pt粒子的表面裸露原子数量,n(PDDA)∶n(Pt)=5∶3为合适的修饰离子用量;发现静电自组装是一个先由大量的小阳离子占据空位,然后由带电大颗粒取代的过程,该体系的自组装在12h完成,此后Pt的组装量(3 2×10-3mg/cm2)和膜的导电能力(0 02S/cm)不再改变。