亲脂性乳化剂的性质和用量对W/O/W型复合乳状液稳定性的影响

研究了亲脂性表面活性剂的性质和用量对W/O/W型复合乳状液稳定性的影响,采用两种类型的亲脂性表面活性剂：新型的聚合型高分子表面活性剂聚氧乙烯（30）二聚羟基硬脂酸脂（Arlacel P135）和传统的小分子表面活性剂Span80和Tween80的混合物（质量比9∶1,HLB=5.4）制备复乳。采用离心保留率、光学显微镜和黏度等方法评价初乳和复乳的稳定性。结果表明,与小分子表面活性剂Span80和Tween80的混合物相比,大分子聚合表面活性剂Arlacel P135可以显著地提高复合乳状液的稳定性,在优化的条件下复乳的稳定性可以达到2000r/min离心15min不分层。     

提高W/O/W多重乳状液的稳定性研究

研究了W／O／W多重乳状液稳定性的影响因素。实验表明，W／O／W多重乳状液制备的较佳工艺操作条件为乳化温度40℃，pH值2．5，W／O／W搅拌时间25min，第一相体积比0．48，第二相体积比0．66。     

第二步乳化工艺参数对W／O／W型复乳稳定性和胰岛素包埋率的影响

研究了用两步乳化法制备W/O/W型复乳时,第二步乳化的乳化工艺参数对复乳的稳定性和药物包埋率的影响规律.以胰岛素为模型药物,用两步乳化法制备W/O/W型复乳,用离心后的乳层保留率评价复乳的稳定性,用高效液相法测定胰岛素在复乳中的包埋率,用激光光散射法测定复乳的粒度分布.实验结果表明,随着第二步乳化过程中乳化强度的提高,复乳滴的粒径减小,复乳的离心稳定性提高而胰岛素包埋率降低.胰岛素包埋率与复乳的粒度分布的关系分为两个区域:当乳化强度较小时,复乳滴的粒径较大,比表面积较小,胰岛素包埋率与体积平均粒径成正比;当乳化强度增大时,复乳滴粒径减小,比表面积增大,胰岛素包埋率与比表面积成反比.在本研究中使胰岛素包埋率最高的第二步乳化过程工艺参数为:VirTishear高速分散均质机分散速度2 000 r/min,分散时间3 min,此工艺下胰岛素的包埋率达到55%.     

蛋白种类对大豆皂苷-蛋白W/O/W型乳液稳定性的影响

将大豆皂苷添加至内水相（W1）,大豆蛋白添加至外水相（W2）,以玉米油为油相（O）,两步乳化法制备W/O/W型多重乳液。探究乳液的整体稳定性、粒径特性、电位特性、微观结构、流变学特性、界面张力以及长期稳定性的变化情况。结果表明：随着时间的延长,乳液的稳定性动力指数值呈上升趋势,粒径集中在6 μm附近,大豆分离蛋白乳液的电位绝对值最大（－30.2 mV）,该体系表现出假塑性的剪切稀化行为,大豆分离蛋白乳液的黏度值最大（0.029 Pa?s）;15 d后,所有蛋白乳液都出现了一定的分层现象,大豆分离蛋白乳液的稳定性动力指数最小（21.51）。在1%蛋白质量分数下,大豆分离蛋白制备的W/O/W型乳液稳定性优于大豆11S和7S蛋白。     

胭脂虫红W/O/W乳液工艺

采用双乳化法制备胭脂虫红W/O/W复合乳液,以纯胭脂虫红酸水溶液作为内水相,大豆油为油相,司盘80、磷脂为亲油性乳化剂,将内水相、油相、亲油性乳化剂混合,在高剪切分散乳化机上以10 000 r/min的转速搅拌10 min,得到初乳。阿拉伯胶溶于水作为外水相,与初乳混合后用均质机均质后得到胭脂虫红W/O/W复合乳液。结果表明,采用双乳化法制备胭脂虫红W/O/W复合乳液,不仅能提高胭脂虫红在酸性条件下的稳定性,还能解决胭脂虫红在食品中形成色斑、不易涂抹问题,并能扩大胭脂虫红在食品领域的使用范围。     

W/O/W型复乳的制备优化及包埋矢车菊素-3-葡萄糖苷效果分析

研究制备方法和乳化剂对W/O/W型复乳稳定性的影响,优化工艺参数,并研究体系包埋矢车菊素-3-葡萄糖苷（cyanidin-3-glucoside,C-3-G）的效果。得到优化条件：初乳搅拌速率15 500 r/min、复乳搅拌速率7 000 r/min、油相乳化剂聚甘油蓖麻醇酯添加量16%、亲水性乳化剂的亲水亲油平衡值10、亲水性乳化剂添加量10%,优化后离心保留率达到80.25%。利用优化得到的复乳体系包裹C-3-G,发现复乳对C-3-G有良好的包裹能力,复乳对C-3-G的载药量为1 500 mg/L,包封率为98.08%,且C-3-G的包埋提高内水相渗透压和复乳稳定性。     

外水相中天然大分子对W/O/W型多重乳状液性质的影响

通过添加天然大分子提高W/O/W型多重乳状液的稳定性。外水相中添加的乳清分离蛋白(WPI)与羧甲基纤维素(CMC)两种物质形成的混合物,可作为亲水性稳定剂来提高乳状液的稳定性。采用两步法制备W/O/W型多重乳状液,研究不同的外水相pH值、WPI与CMC的比例和添加量对W/O/W型多重乳状液性质的影响;以粒径、zeta-电位、黏度、稳定性等指标确定W/O/W型多重乳状液的最优制备条件。研究结果表明:当pH=6时,WPI与CMC的比例10∶1,添加量4.4%,WPI与CMC相互作用形成的混合物吸附在油水界面,形成的界面膜的厚度及韧性较好,W/O/W型多重乳状液的粒径较小,稳定性较高(79%)。     

基于熊果酸的W/O/W型Pickering乳液制备方法

目的:提高熊果酸的应用范围和生物利用率。方法:以熊果酸为乳化剂,果胶为外水相,采用两步法制备W/O/W型Pickering乳液。通过单因素试验优化W/O乳液制备条件,研究果胶质量浓度对W/O/W型Pickering乳液理化性质、微观结构、流变学特性及长期稳定性的影响。结果:W/O乳液的最佳制备工艺为熊果酸质量浓度4 g/100 mL、水油质量比2∶3、均质转速9 000 r/min、均质时间5 min;以果胶为外水相制备的双层乳液粒径均在30～40μm,果胶质量浓度的增加使乳液的zeta电位绝对值、流变性能以及4℃贮藏稳定性有着显著性的提高。结论:果胶质量浓度为0.3,0.4,0.5 g/100 mL时能够制备稳定的Pickering双层乳液。     

高压电场制备W/O/W复乳微囊的试验研究

为探索水溶性物质微囊化新方法，利用高压电场微胶囊成型装置制备W／O／W型微囊，内水相为蒸馏水，油相为液体石蜡，外水相为海藻酸钠溶液。研究了电压、液面距、推进速度、初乳／外相水溶液、海藻酸钠浓度对微囊粒径的影响。结果表明：在成囊范围内，电压、液面距和外水相海藻酸钠溶液浓度对微囊的粒径有较为显著的影响。在电压3．15kV～4kV，液面距2．5cm-10cm，海藻酸钠浓度0．6％～1．2％，可以制得微囊粒径范围为50μm-1000μm，大小均匀的复乳微囊。     

W/O/W多重乳状液的实验研究

研究了W/O/W多重乳状液的制备方法及影响其稳定性的因素。通过正交试验选出较佳的工艺参数,获得了较稳定的W/O/W多重乳状液。     

米糠蛋白O/W及W/O/W乳液制备及界面稳定性

为对比不同米糠蛋白质量浓度下O/W及W/O/W乳液的稳定性,以米糠蛋白作为基料,采用双乳化法制备O/W及W/O/W乳液,考察不同米糠蛋白质量浓度下乳液的微观形态和稳定性并探究其界面稳定机理。结果表明：W/O/W乳液的贮存稳定性显著优于O/W乳液;与相同蛋白含量的O/W乳液相比,W/O/W乳液的黏度显著提高;当米糠蛋白质量浓度为0.4 g/100 mL时,W/O/W乳液的稳定性较O/W乳液提高了1 倍以上;乳液内部包裹更多的W/O液滴,W/O/W乳液的粒径较大;而此时静电斥力也较大,起到稳定乳液的目的。同时,米糠蛋白质量浓度不小于0.4 g/100 mL时,O/W及W/O/W乳液中蛋白质的吸附率较高,达到78%以上。本研究为天然米糠蛋白质在食品级乳液中的开发提供参考,为粮食副产物的综合利用提供了新思路。     

Release rate profiles of magnesium from multiple W/O/W emulsions

Water-in-oil-in-water (W/O/W) emulsions were formulated based on rapeseed oil, olive oil, olein and miglyol. Polyglycerol polyricinoleate and sodium caseinate were used as lipophilic and hydrophilic emulsifiers, respectively. Magnesium was encapsulated in the inner aqueous droplets. Emulsion stability was assayed through particle sizing and magnesium release at two storage temperatures (4 and 25 °C) over 1 month. Irrespective of the oil nature, both the primary W/O and W/O/W emulsions were quite stable regarding the size parameters, with 10-μm fat globules and 1-μm internal water droplets. Magnesium leakage from W/O/W emulsions was influenced by the oil type used in the formulation: the higher leakage values were obtained for the oils characterized by the lower viscosity and the higher proportion of saturated fatty acids. Magnesium release was not due to droplet–globule coalescence but rather to diffusion and/or permeation mechanisms with a characteristic rate that varied over time. In addition, W/O/W emulsions were resistant to various thermal treatments that mimicked that used in pasteurization processes. Finally, when W/O/W emulsions were placed in the presence of pancreatic lipase, the emulsion triglycerides were hydrolysed by the enzyme. These results indicated a possible use of W/O/W emulsions loaded with magnesium ions in food applications.     

W/O emulsions: solvent phase separation for pH determination

The aim of this investigation was to find a measure for the phase separation by substances capable of rapidly demulsifying emulsions, which is necessary for the correct determination of the pH in cosmetic W/O emulsions. Results are reported for pH determination in the separated water phase of W/O emulsions containing metal soaps, micropigments and thermally unstable active agents. Of the substances investigated – solvents of different polarity and electrolytes – the best were mixtures of the polar butanol, which has a surfactant-like molecular structure and limited oil and water solubility, and the low polar trichloromethane which in particular has strong fat- and wax-dissolving properties. The combination achieved within 10 to 20 min at room temperature complete phase separations. Stable preparations, based on a polymer emulsifier (cetyl dimethicone copolyol), were demulsified as well as metal soap stabilized creams which characteristically contain a high amount of stabilizing waxes. The so-called solvent phase separation method was confirmed by using model preparations of known pH. During the investigation of model emulsions matching those used in practice, it was found, for example, that magnesium and aluminium stearate as well as various types of micronized zinc oxide which are dissolved or dispersed in the oil phase can shift the pH of the aqueous phase during manufacture from an initial acidic value through neutral to pH 8–10. Time-related and temperature-related changes in pH in formulations containing thermally unstable additives such as dihydroxyacetone or urea can be easily monitored.     

O/W emulsion and W/O/W multiple emulsion: physical characterization and skin pharmacokinetic comparison in the delivery process of caffeine

The aim of this study was to compare the characteristics of an O/W emulsion and a W/O/W emulsion, formulated with similar ingredients. The physical properties of these two types of vehicles were characterized first. Using three types of in vitro models, human skin biopsies, nitrate acetate cellulose membranes and human reconstituted epidermis, the delivery potential of each vehicle for one hydrophilic drug, caffeine, was compared. The assessment of physical parameters, such as particle size, conductivity and rheological behavior enabled the nature of the test emulsions to be clearly identified. Clear differences were observed in the ability of each type of emulsion to deliver caffeine. Whatever the nature of the membrane used for the pharmacokinetic study, the absorption of caffeine was roughly two-fold lower (2.6 for human skin) when the W/O/W multiple emulsion was used as the vehicle. The concomitant determination of physical and kinetic properties of these two test emulsions allowed the W/O/W multiple emulsion and a simple O/W emulsion to be clearly differentiated.     

The characterization of the semi-solid W/O/W emulsions with low concentrations of the primary polymeric emulsifier

Semi-solid multiple W/O/W emulsions with low concentrations (0.8, 1.6 and 2.4% w/w) of lipophilic polymeric primary emulsifier PEG-30-dipolyhydroxystearate (PDHS) have been formulated. Both emulsions, primary and multiple, were prepared with high content of inner phase (Phi1 = Phi2 = 0.8). All the formulations differ only in the lipophilic emulsifier concentration. Evaluating several parameters such as macroscopic and microscopic aspect, droplet size, accelerated stability under centrifugation and flow and oscillatory rheological behaviour, assessed the multiple systems. It is possible to formulate the semi-solid W/O/W multiple emulsions with low concentrations of PDHS as the primary emulsifier. It appeared that the highest long-term stable multiple emulsion with the lowest droplet size, the highest apparent viscosity and highest elastic characteristic, was the sample with the highest concentration (2.4% w/w) of the primary emulsifier.