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排序方式: 共有412条查询结果,搜索用时 250 毫秒
1.
In this review, we discuss the application of cellulose nanoparticles as a sustainable and cost-effective source of green stabilizers for formulation of foodstuff. Fibrillar cellulose nanocrystal and nanofibril stabilize Pickering systems because of their ability to adsorb at the oil/water interfaces, forming protective layers. They also form associative structures in the continuous phase, increasing their viscoelastic properties and preventing flocculation. We describe the chemical and structural features of nanocelluloses and discuss the principles that support their utilization as stabilizers, especially in the context of recent prospects in food and health domains, given safety and regulatory advances. In addition, we describe the benefits of combining nanocelluloses with other food ingredients to extend their functional attributes. Particularly, nanocellulose-based Pickering emulsions are used to create edible soft materials with multiple functionalities. This article is expected to stimulate the use of nanocelluloses as functional ingredients to create food products with improved performance and novel properties. 相似文献
2.
A drug nanocrystals self-stabilized Pickering emulsion (NSSPE) with a unique composition and microstructure has been proven to significantly increase the bioavailability of poorly soluble drugs. This study aimed to develop a new solid NSSPE of puerarin preserving the original microstructure of NSSPE by spray-drying. A series of water-soluble solid carriers were compared and then Box-Behnken design was used to optimize the parameters of spray-drying. The drug release and stability of the optimized solid NSSPE in vitro were also investigated. The results showed that hydroxypropyl-β-cyclodextrin (HP-β-CD), rather than solid carriers commonly used in solidification of traditional Pickering emulsions, was suitable for the solid NSSPE to retain the original appearance and size of emulsion droplets after reconstitution. The amount of HP-β-CD had more influences on the solid NSSPE than the feed rate and the inlet air temperature. Fluorescence microscopy, confocal laser scanning microscopy and scanning electron microscopy showed that the reconstituted emulsion of the solid NSSPE prepared with HP-β-CD had the same core-shell structure with a core of oil and a shell of puerarin nanocrystals as the liquid NSSPE. The particle size of puerarin nanocrystal sand interfacial adsorption rate also did not change significantly. The cumulative amount of released puerarin from the solid NSSPE had no significant difference compared with the liquid NSSPE, which were both significantly higher than that of puerarin crude material. The solid NSSPE was stable for 3 months under the accelerated condition of 75% relative humidity and 40 °C. Thus, it is possible todevelop the solid NSSPE preserving the unique microstructure and the superior properties in vitro of the liquid NSSPE for poorly soluble drugs. 相似文献
3.
4.
Anaïs Giustiniani Philippe Gugan Manon Marchand Christophe Poulard Wiebke Drenckhan 《Macromolecular rapid communications》2016,37(18):1527-1532
Macrocellular silicone polymers are obtained after solidification of the continuous phase of a poly(dimethylsiloxane) emulsion, which contains poly(ethylene glycol) drops of sub‐millimetric dimensions. Coalescence of the liquid template emulsion is prohibited by a reactive blending approach. The relationship is investigated in detail between the interfacial properties and the emulsion stability, and micro‐ and millifluidic techniques are used to generate macrocellular polymers with controlled structural properties over a wider range of cell sizes (0.2–2 mm) and volume fractions of the continuous phase (0.1%–40%). This approach could easily be transferred to a wide range of polymeric systems.
5.
Highly concentrated oil-in-water (o/w) emulsion stabilised by means of gluten and soya protein isolate (SPI) at low pH have
been characterized by means of linear dynamic viscoelasticity and droplet size distribution analysis (DSD). The microstructure
of these emulsions has been characterized at a colloidal level by using confocal laser scanning microscopy (CLSM) and light
microscopy (LM). These emulsions always exhibited a behaviour characteristic of highly flocculated emulsions with a mechanical
spectrum showing a well-developed plateau region. DSD results generally showed log normal bimodal profiles. Microstructure
images revealed occurrence of a close packing of droplets with a broad distribution of sizes participating in the formation
of a three dimensional flocculated network. The Mason model of elasticity of compressed emulsions has been used to correlate
viscoelastic and microstructural parameters giving adequate fitting but underestimating the elastic properties obtained for
the highest concentration of gluten. These deviations may be explained in terms of an enhancement of the elastic network formed
in the aqueous phase in which the glutenin fraction must play an important role.
Paper presented at the Annual European Rheology Conference (AERC) 2005, April 21-23, Grenoble, France. 相似文献
6.
《Analytical letters》2012,45(9):1615-1622
Abstract A simple and rapid method for the simultaneous determination of seven trace elements in biodiesel by axial and radial view Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) is proposed, in which the sample is emulsified with Triton X-100 and water, and in which yttrium is employed as an internal standard. The better obtained quantification limits (10 s) were by axial view, 0.165, 0.099, 0.033, 0.007, 0.016, 0.132, 0.660 µg g?1 for Ca, Cu, Fe, Mg, Mn, Na, and P, respectively, based on a sample mass of 1.0 g diluted to a final mass of 10 g in the analytical solution. Calibration was carried out with aqueous standards, thus avoiding the use of frequently instable organic standards. Elemental recoveries were in the range of 90 to 109% for all seven analytes studied, and also the precision of the method was satisfactory (RSD < 8%). 相似文献
7.
Benjamin ZeebMonika Gibis Lutz FischerJochen Weiss 《Journal of colloid and interface science》2012,387(1):65-73
The influence of interfacial crosslinking, layer thickness and layer density on the kinetics of Ostwald ripening in multilayered emulsions at different temperatures was investigated. Growth rates of droplets were measured by monitoring changes in the droplet size distributions of 0.5% (w/w) n-octane, n-decane, and n-dodecane oil-in-water emulsions using static light scattering. Lifshitz-Slyozov-Wagner theory was used to calculate Ostwald ripening rates. A sequential two step process, based on electrostatic deposition of sugar beet pectin onto fish gelatin or whey protein isolate (WPI) interfacial membranes, was used to manipulate the interfacial properties of the oil droplets. Laccase was added to the fish gelatin-beet pectin emulsions to promote crosslinking of adsorbed pectin molecules via ferulic acid groups, whereas heat was induced to promote crosslinking of WPI and helix coil transitions of fish gelatin. Ripening rates of single-layered, double-layered and crosslinked emulsions increased as the chain length of the n-alkanes decreased. Emulsions containing crosslinked fish gelatin-beet pectin coated droplets had lower droplet growth rates (3.1 ± 0.3 × 10−26 m3/s) than fish gelatin-stabilized droplets (7.3 ± 0.2 × 10−26 m3/s), which was attributed to the formation of a protective network. Results suggest that physical or enzymatic biopolymer-crosslinking of interfaces may reduce the molecular transport of alkanes between the droplets in the continuous phase. 相似文献
8.
Bernice H. L. Oh Alexander Bismarck Mary B. Chan‐Park 《Macromolecular rapid communications》2015,36(4):364-372
High‐porosity interconnected, thermoresponsive macroporous hydrogels are prepared from oil‐in‐water high internal phase emulsions (HIPEs) stabilized by gelatin‐graft‐poly(N‐isopropylacrylamide). PolyHIPEs are obtained by gelling HIPEs utilizing the thermoresponsiveness of the copolymer components. PolyHIPEs properties can be controlled by varying the aqueous phase composition, internal phase volume ratio, and gelation temperature. PolyHIPEs respond to temperature changes experienced during cell seeding, allowing fibroblasts to spread, proliferate, and penetrate into the scaffold. Encapsulated cells survive ejection of cell‐laden hydrogels through a hypodermic needle. This system provides a new strategy for the fabrication of safe injectable biocompatible tissue engineering scaffolds.
9.
Tailoring of High‐Order Multiple Emulsions by the Liquid–Liquid Phase Separation of Ternary Mixtures 下载免费PDF全文
Martin F. Haase Jasna Brujic 《Angewandte Chemie (International ed. in English)》2014,53(44):11793-11797
Multiple emulsions with an “onion” topology are useful vehicles for drug delivery, biochemical assays, and templating materials. They can be assembled by ternary liquid phase separation by microfluidics, but the control over their design is limited because the mechanism for their creation is unknown. Herein we show that phase separation occurs through self‐similar cycles of mass transfer, spinodal decomposition or nucleation, and coalescence into multiple layers. Mapping out the phase diagram shows a linear relationship between the diameters of concentric layers, the slope of which depends on the initial ternary composition and the molecular weight of the surfactant. These general rules quantitatively predict the number of droplet layers (multiplicity), which we used to devise self‐assembly routes for polymer capsules and liposomes. Moreover, we extended the technique to the assembly of lipid‐stabilized droplets with ordered internal structures. 相似文献
10.
Simultaneous Detection of Single Attoliter Droplet Collisions by Electrochemical and Electrogenerated Chemiluminescent Responses 下载免费PDF全文
Jeffrey E. Dick Dr. Christophe Renault Dr. Byung‐Kwon Kim Prof. Dr. Allen J. Bard 《Angewandte Chemie (International ed. in English)》2014,53(44):11859-11862
We provide evidence of single attoliter oil droplet collisions at the surface of an ultra‐microelectrode (UME) by the observation of simultaneous electrochemical current transients (i–t curves) and electrogenerated chemiluminescent (ECL) transients in an oil/water emulsion. An emulsion system based on droplets of toluene and tri‐n‐propylamine (2:1 v/v) emulsified with an ionic liquid and suspended in an aqueous continuous phase was formed by ultrasonification. When an ECL luminophore, such as rubrene, is added to the emulsion droplet, stochastic events can be tracked by observing both the current blips from oxidation at the electrode surface and the ECL blips from the follow‐up ECL reaction, which produces light. This report provides a means of studying fundamental aspects of electrochemistry using the attoliter oil droplet and offers complementary analytical techniques for analyzing discrete collision events, size distribution of emulsion systems, and individual droplet electroactivity. 相似文献