共查询到19条相似文献,搜索用时 140 毫秒
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为改善β-胡萝卜素的水相溶解性及生物利用率,采用淀粉纳米晶(SNC)为颗粒乳化剂稳定Pickering乳液,对β-胡萝卜素进行乳化包埋。考察了油相体积分数和β-胡萝卜素含量对运载β-胡萝卜素的Pickering乳液储藏稳定性的影响。结果显示,当SNC含量为1%(以水相质量为基准),油相(溶有β-胡萝卜素的辛酸/癸酸甘油三酯)体积分数为50%,β-胡萝卜素含量为0.050%(以油相的质量为基准)时,采用含量为0.80%(以水相的质量为基准)的季铵盐壳聚糖(QCS)对Pickering乳液进行修饰后,乳液的乳析现象可明显改善,且储藏稳定性显著提高。体外模拟消化实验结果显示,QCS修饰后乳液中油脂的消化程度由56.68%±1.56%提高到71.70%±2.13%,β-胡萝卜素的生物可给率由33.59%±0.82%提高到57.62%±1.58%。采用QCS进行修饰不仅可以提高β-胡萝卜素Pickering乳液的稳定性,还可以提高乳液中油脂的消化程度和β-胡萝卜素的生物可给率。 相似文献
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通过Ugi反应疏水改性海藻酸钠(Alg),制备了两亲性的海藻酸衍生物(Ugi-Alg)。以聚甲基氢硅氧烷(PMHS)作为疏水改性剂,利用干法球磨对高岭土(KL)微粒表面疏水改性。并利用FTIR、1HNMR、接触角测量仪、激光粒度和Zeta电位分析仪对改性产物进行表征。用改性后的高岭土(MKL)协同Ugi-Alg制备稳定的Pickering乳液,并探究了水相p H对Pickering乳液形貌和液滴大小的影响。结果表明:Alg通过Ugi反应成功地疏水改性;PMHS在球磨的机械作用下吸附在KL微粒表面,使MKL成为具有高疏水性能的活性微粒;Ugi-Alg在超声作用下协同吸附在MKL微粒表面,改变了MKL微粒表面的润湿性,可提高Pickering乳液的稳定性;随着水相p H的升高,MKL/Ugi-Alg稳定的Pickering乳液液滴粒径逐渐减小,当p H=10.32时,其液滴粒径达到7.4μm。 相似文献
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采用生物法合成了高纯度的细菌纤维素(BC),通过浓硫酸水解制得细菌纤维素纳米晶(BCN)。以液体石蜡为油相,BCN为固体乳化剂,在超声作用下制得O/W型Pickering乳液。通过SEM,TEM,FT-IR,XRD,接触角测量仪及激光粒度和Zeta电位分析仪对BC及BCN进行了表征。考察了BCN质量浓度、水相p H和离子强度对Pickering乳液稳定性的影响。结果表明,BC在浓硫酸水解过程中发生了氧化反应,其水解主要发生在无定型区,使所得BCN的结晶指数高达97%。BCN悬浮液的粒径和Zeta电位值分别为462.5 nm和-40.8 m V,其三相接触角为95.7°,具有良好的乳化性能。在超声乳化作用下制得的乳液粒径大小为8.6~17.3μm。通过调控水相p H能够改变BCN表面电荷密度,从而改变乳液的稳定性,随着水相p H的增大,乳液相体积分数增大,乳液稳定性增强。随着Na Cl浓度的增大,乳液的稳定性降低,乳液相体积分数减小。此外,SEM的观测结果表明,BCN在稳定Pickering乳液过程中呈现纤维线条和聚集体颗粒2种形态。 相似文献
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以钠基蒙脱土(Na-MMT)为原料,采用湿法球磨法制备双十二烷基二甲基溴化铵(DDAB)插层的改性蒙脱土(DDA-MMT),并在超声作用下乳化液体石蜡制得O/W型Pickering乳液。通过XRD、TEM、FT-IR、接触角测量仪和Zeta电位及激光粒度仪对DDA-MMT进行了表征。考察了DDA-MMT颗粒质量浓度、水相p H和离子强度对Pickering乳液稳定性的影响。实验结果表明,在球磨机械力作用下DDAB成功插入Na-MMT的片层间,使Na-MMT的平均粒径、Zeta电位和三相接触角分别由910.7 nm,-26.8 m V和121.7°变为603.8 nm,38.3 m V和86.9°。与Na-MMT颗粒相比,DDA-MMT颗粒更容易在油/水界面间聚集而具有更好的乳化稳定性。随着DDA-MMT颗粒质量浓度的增大,Pickering乳液液滴粒径减小,乳液体积分数增大,稳定性增强。当水相p H=6.26~8.36,c(Na Cl)=20 mmol/L时,由DDA-MMT颗粒乳化制备的Pickering乳液稳定性较佳。 相似文献
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将淀粉纳米晶(SNC)与带正电的季铵盐壳聚糖(QCS)复配,制备了稳定的Pickering乳液。通过FTIR、表/界面张力、流变仪、光学显微镜、荧光显微镜分别对QCS/SNC分散液Pickering乳液的性能进行表征。结果表明,QCS通过氢键作用和静电作用吸附在SNC颗粒表面,QCS的加入使SNC水溶液的分散性提高、表面张力和界面张力降低。随着QCS质量分数的增加,乳液粒径呈现先增大后减小又增大的趋势;当QCS的质量分数为0.4%时,QCS/SNC稳定的乳液粒径最小,且室温储存30 d后仍无乳析现象。 相似文献
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采用辛胺疏水改性海藻酸钠合成了具有两亲性的高分子表面活性剂海藻酸辛酰胺(OAAD),并将其与SiO2纳米颗粒协同制备了稳定的Pickering乳液。通过FTIR、1HNMR、表面张力、荧光光谱、动态光散射、接触角测量、光学显微镜分别对OAAD、OAAD/SiO2纳米颗粒水分散体系和Pickering乳状液的性能进行了表征。结果表明,辛胺氨基成功接枝到海藻酸钠(SA)分子链上,OAAD界面张力较SA降低、临界聚集质量浓度为0.60 g/L,表现出良好的两亲性。将OAAD吸附在SiO2纳米颗粒表面形成的水分散体系用于稳定Pickering乳液时,发现随着OAAD质量浓度增加,SiO2纳米颗粒润湿性增加,Zeta电位减少,粒径增加;而乳液的粒径则逐渐减少,稳定性增强,其机理经初步分析为,当一定浓度的OAAD吸附在SiO2纳米颗粒表面,可导致颗粒间絮凝,从而在油水界面形成网络结构式界面膜,有利于提高Pickering乳液的稳定性。 相似文献
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Pickering乳液是指由微纳米固体粒子代替传统表面活性剂作为乳化剂而稳定的乳液,具有较强的稳定性和超高油/水界面,能够为多相界面反应和物质传输提供高效稳定的场所。Pickering乳液的乳滴结构和性质与固体颗粒的尺寸形貌及表面性质密不可分,通过调控固体颗粒本身或表面的性质可以赋予Pickering乳液特定的响应性功能,拓宽其应用领域。本文对近年来不同响应型(磁性、CO2、pH、光、温度等响应型)的Pickering乳液的主要研究成果进行了综述,重点介绍了Pickering乳液的稳定性原理、响应型Pickering乳液的制备方法和结构调控策略,以及近年来Pickering乳液在物质分离提取中的应用研究进展,最后对智能响应型Pickering乳液应用研究的发展趋势进行了展望。 相似文献
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Pickering emulsions are potential industrial scale alternatives to surfactant-based emulsions. The stability of Pickering emulsions depends on the physicochemical nature of the liquid–particle interface and the hydrodynamic conditions of the production process. This article investigates the effect of hydrodynamic conditions on the drop size of concentrated Pickering emulsions in baffled stirred tanks. Oil in water emulsions composed of silicon oil, water, and hydrophilic glass beads as stabilizing particles were produced. Two impellers were used at different sizes: Rushton turbine (RT) and pitched blade turbine. The effects of power per mass, Reynolds number, tip speed, and Weber number on the droplet sizes were studied. The energy dissipated around the impeller and the size of the impeller high shear zone were found to be critical to the emulsion droplet sizes. The breakup and droplet-particle contact mechanism of the RT was found to be more favorable for the production of the Pickering emulsions. 相似文献
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为了探究固体粒子对乳液的稳定作用,采用L-赖氨酸作为催化剂合成纳米SiO2粒子,并用六甲基二硅胺烷(HMDS)对纳米SiO2粒子进行表面疏水改性,将经过HMDS改性后的纳米SiO2粒子作为稳定剂制备出Pickering乳液。通过粒径分析仪、场发射透射电子显微镜、FTIR、TG-DSC、接触角测量仪、光学显微镜、电导率仪分别对纳米SiO2的制备、表面改性和Pickering乳液的性能进行了表征。结果表明,成功合成出粒径小且形貌均一的硅球,具有疏水性的三甲基硅基成功接枝到纳米SiO2的表面;不同纳米SiO2浓度制备的Pickering乳液,发现随着SiO2浓度的增大,乳液的稳定性逐渐增强,乳液液滴直径呈现减小的趋势;不同油水比制备的Pickering乳液,发现随着油相体积的增大,乳液的稳定性呈现增大的趋势。 相似文献
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The aim of this study was to investigate the effect of feed time of the oil phase on the average droplet size of Pickering emulsions produced in stirred tanks. Three types of impellers were tested: RT, up-pumping PBT (PBTU), and down-pumping PBT (PBTD). All the impellers were tested at two sizes, T/3 and T/2. All configurations were compared at constant tip speed, power per mass, and impeller Reynolds number. The droplet diameters were measured in Mastersizer® 3,000 (Malvern). The results showed that an increase in feed time causes a reduction in the average droplet size. At lower impeller speeds and higher feed times, the effect is more pronounced. It was found that some other geometric parameters also have an impact on the average droplet size. 相似文献
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Poly(3,4‐ethylenedioxythiophene) (PEDOT) doped with a series of anionic polysaccharides such as carboxymethyl cellulose, sodium hyaluronate, xanthan gum, pectin, gellan gum were prepared by electropolymerization in aqueous solutions. Some other dopants of potassium nitrate, potassium sulfate, sodium poly(styrenesulfonate), and sodium polyacrylate were used in comparison with the anionic polysaccharides. The electrochemical properties and stability of the obtained PEDOT films were also investigated. It was found that indium tin oxide (ITO) conductive glass could be used as the working electrode of the electropolymerization of EDOT and that the dopant had a great influence on polymerization potential and overoxidation potential. These charged biomolecules of anionic polysaccharides were found to facilitate electropolymerization of EDOT instead of common doping anions as counterion. The electroactive PEDOT films doped with anionic polysaccharides showed stable electrochemical properties, good texture, and adhesion properties to the ITO conductive glass. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
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Partha Kundu Vimal Kumar Peter J. Scales Indra Mani Mishra 《Journal of surfactants and detergents》2019,22(2):301-313
The influence of emulsion pH and temperature on the rheological behavior of adhesive oil-in-water (o/w) emulsions stabilized with an anionic surfactant (sodium dodecyl benzene sulfonate, SDBS) was studied. The flow properties of emulsions as a complex fluid were investigated using steady and dynamic rheometry for characterization of non-Newtonian behavior. Emulsion pH was varied from 2 to 12 and temperature was varied from 20 to 50 °C, respectively. The influences of the above-mentioned variables on the rheology of o/w emulsion were studied using steady-shear and dynamic oscillatory experiments. Various viscosity models (2, 3, and 4 parameter rheological model) were used to predict the rheological parameters. An increase in the pH of the emulsion led to an increase in the emulsion stability, viscosity, and viscoelastic properties ( G′ , G″ , η* , and tan δ ), and a decrease in the mean droplet size of the emulsion. A decrease in the temperature yields higher values of steady-shear viscosity and viscoelastic properties upon a decrease in droplet size. Emulsions were characterized as flocculated structured liquid exhibiting a characteristic crossover frequency ( ω* ) within the range of angular frequency studied in oscillatory measurements. Overall, emulsions exhibited non-Newtonian shear-thinning behavior and the synergy of pH and temperature significantly influences the emulsion rheology. 相似文献
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《Carbon》2014
Gold nanoparticle/graphene oxide hybrids (AuNP/GO) were easily fabricated by a redox reaction between GO and chloroauric acid without using any additional reductant and then used to stabilize Pickering emulsions. Factors affecting the properties of the emulsions were studied, including the HAuCl4/GO mass ratio used to prepare the AuNP/GO, the oil/water ratio, the AuNP/GO concentration, the pH value, and the type and concentration of electrolytes. The emulsions were more stable when stabilized by AuNP/GO made from HAuCl4/GO mass ratios of 0.375–0.5. High pH values and AuNP/GO concentrations that were too high or too low were unfavorable to the stability of the Pickering emulsions. Adding electrolytes to the systems improved the stability of the Pickering emulsions owing to the reduction of repulsive interactions between AuNP/GO sheets. The AuNP/GO stabilized Pickering emulsions were used to prepare AuNP/GO supported polystyrene (PS) microspheres (AuNP/GO@PS) by polymerizing the Pickering emulsion. The catalytic performance of AuNP/GO@PS for the reduction of 4-nitrophenol was then studied. 相似文献
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Morten J. Dille Kurt I. Draget 《European Journal of Lipid Science and Technology》2021,123(2):2000282
Gelatin-based chewable emulsions can be a convenient vehicle for oral delivery of oils or lipid soluble bioactive components. Gelatin-stabilized emulsions do, however, rapidly flocculate and gradually coalesce in gastric fluids. This destabilization is caused by the combined action of pepsin and mucin and is most significant at pH 3, followed by pH 2, then pH 4. Through in vitro lipolysis experiments it is shown that this destabilization leads to a decrease in emulsion lipolysis rate after incubation in simulated gastric fluids (SGFs). In this paper a potential solution to this gastric instability is suggested: inclusion of 1 wt% sodium-κ-carrageenan (κ-CGN) of intermediate Mw into the gelatin emulsions. The κ-CGN used has minimal impact on gelatin gelled emulsion properties, preserving the soft elastic gelatin texture. When these gelled emulsions disintegrate in gastric fluids, electrostatic interactions between the gelatin and κ-CGN occur. While these interactions lead to heavy flocculation, they also protect the gelatin from pepsin action, providing full stability against emulsion coalescence during at least 2 h in SGF at pH 2–4. When the pH is neutralized upon mixing with intestinal fluids, the emulsion fully deflocculates and the rate of in vitro lipolysis is not affected by gastric residence time. Practical applications: Avoiding gastric coalescence in gelatin emulsions may lead to more reliable oral delivery of lipids or lipophilic components in gelatin-based chewable supplements or functional foods. Keeping the emulsion droplet size stable and small until reaching the intestine may lead to more rapid and efficient intestinal lipolysis, potentially advantageous in regards to bioavailability of slowly digested oils (e.g., omega-3 concentrate) or for people suffering from impaired lipid digestion. These findings may also be applicable to emulsion systems stabilized by other proteins. 相似文献