Search results for "Emulsion"
showing 10 items of 344 documents
Inducing mixing of water-in water BSA/dextran emulsion by a strong polyelectrolyte
2015
Abstract We examine whether a small amount of strong polyelectrolyte (dextran sulfate sodium salt/DSS/) can induce mixing in water-in-water bovine serum albumin/dextran (BSA/DEX) emulsion and how intermacromolecular interactions affect its the rheological properties. Addition of DSS to water-in-water emulsion at pH 5.4 leads to its mixing at the DSS/BSA weight ratio, ( q ( DSS / BSA ) ) ≥ 0.07 , a noticeable increase in viscosity and storage modulus (G′). Mixing is reversible: increasing the ionic strength leads to phase separation in the water/BSA/DEX/DSS system. The increase in viscoelasticity results from the interaction of DSS with both macromolecular compounds of the emulsion. We assum…
Relevance of creep and oscillatory tests for understanding how cellulose emulsions function as fat replacers in biscuits
2015
Abstract The fats that are mostly employed in biscuit manufacturing contain a high percentage of saturated fatty acids, giving them the solid consistency that is needed for biscuit manufacture. For health reasons, lower levels of saturated fatty acids and elimination of trans fatty acids are desirable. An emulsion of sunflower oil, water and a cellulose ether was employed to replace all the conventional fat in a short dough recipe. The structure of the different doughs was measured by oscillatory and creep rheological tests and the results were related to dough performance during baking. The effect of the methoxyl and hydroxypropyl content of the cellulose was also evaluated. The compliance…
Influence of emulsion and powder size on the stability of encapsulated d-limonene by spray drying
2005
Abstract The microencapsulation of d -limonene by spray drying was investigated with respect to the effects of emulsion droplet size, powder particle size, as well as to the effects of various kinds of matrices (gum arabic, maltodextrin, and modified starch) on its stability. It was realized by studying release characteristics and oxidative stability during storage. The release and the oxidation decreased deeply with an increase in powder and emulsion particle size for gum arabic and maltodextrin materials. Further, the distributions of emulsion size in the powder showed an increase in the fraction of large emulsion droplets and changed to a bimodal distribution. However, the modified starc…
Properties of spray-dried food flavours microencapsulated with two-layered membranes: Roles of interfacial interactions and water
2012
International audience; Engineering the interface of oil-in-water emulsion droplets with biopolymers that modify its permeability could provide a novel technique to improve flavour retention in dry powders. The objective of this study was to determine if volatile compounds were more retained in dry emulsions stabilized by pea protein isolate (PPI)/pectin complex than that stabilized by PPI alone. The retention of ethyl esters during spray-drying increased with decreasing volatility of the encapsulated compound and ranged from 28% to 40%. The addition of pectin to feed emulsions was quite effective in markedly improving the retention of the three studied flavour compounds. In our previous wo…
Structural and dynamical investigation of gelation containing water-in-oil microemulsions
1996
The gelatin (Bloom 300)/water/AOT/n-heptane system has been investigated at fixed water/AOT molar ratioR (R=31.1) as a function of the gelatin content. Several experimental techniques (densitometry, refractometry, conductometry, rheology, dielectrometry, ultrasonics, hypersonics) have been used to investigate the role played by the gelatin molecule in the observed sol-gel transition above a critical gelatin content. The results appear consistent with the hypothesis of a rigid network of gelatin-water rods coated by surfactant molecules coexisting with gelatin-free AOT reversed micelles at the gelation point.
Circular dichroism of polynucleotides: Interactions of NiCl2 with poly(dA-dT).poly(dA-dT) and poly(dG-dC).poly(dG-dC) in a water-in-oil microemulsion.
2008
The thermal behavior of the synthetic, high molecular weight, double stranded polynucleotides poly(dA-dT)·poly(dA-dT) [polyAT] and poly(dG-dC)·poly(dG-dC) [polyGC] solubilized in the aqueous core of the quaternary water-in-oil cationic microemulsion CTAB|n-pentanol|n-hexane|water in the presence of increasing amounts of NiCl2 at several constant ionic strength values (NaCl) has been studied by means of circular dichroism and electronic absorption spectroscopies. In the microemulsive medium, both polynucleotides show temperature-induced modifications that markedly vary with both Ni(II) concentration and ionic strength. An increase of temperature causes denaturation of the polyAT duplex at lo…
Induced Chirality in Confined Space on Halogen Gold Complexes
2015
The solubilization of HAuCl4 in toluene within optically active reverse micelles and lamellar structures formed by (1R,2S)-Dodecyl(2-hydroxy-1-methyl-2-phenylethyl)- dimethylammonium bromide (DMEB) has allowed us to evidence the complex phenomenology accompanying the confinement of Au salt within these nanostructures. Together with a chloride/bromide exchange process occurring in the first coordination sphere of an Au ion, UV−vis and electronic circular dichroism (ECD) spectra reveal the appearance of an induced dichroic signal attributable to Au complexes entrapped in the hydrophilic domain of the DMEB chiral nanostructures. Interestingly, change of the effective oxidation state and coordi…
Microemulsion encapsulated into halloysite nanotubes and their applications for cleaning of a marble surface
2018
Halloysite nanotubes were used to incorporate anionic surfactant micelles and an organic solvent to generate a cleaning system to be applied in Cultural Heritage restoration. The targeted adsorption is driven by electrostatic interactions based on the nanotubes peculiar charge separation. Namely anionic species are driven to the positively charged inner surface while being prevented from interacting with the halloysite outer surface that possesses a positive charge density. The hybrid organic/inorganic emulsion was characterized by dynamic light scattering. Analysis of the autocorrelation function allowed us to define the presence of surfactant aggregates inside/outside the nanotube lumen a…
Electrokinetic capillary chromatography in a polar continuous‐phase water‐in‐oil microemulsion constituted by water, sodium dodecyl sulfate, and n ‐p…
2005
A water-in-oil (w/o) microemulsion (ME) constituted by 15% Tris buffer, pH 8.4, in water and 85% sodium dodecyl sulfate (SDS)/n-pentanol 1:4 mixture, capable of dissolving up to 30% vegetable oils and lard, was used as background electrolyte in reverse microemulsion electrokinetic capillary chromatography (RMEEKC). Owing to the free SDS ions in the continuous phase and some degree of percolation, the ME showed a high conductivity (0.65 mS. cm(-1) at 25 degrees C) and sustained a very stable capillary current. Previous rinsing of the capillary with a quaternary ammonium salt for electroosmotic flow (EOF) reduction, a series of nonionic and anionic solutes dissolved either in the ME or in fat…
Polyorganosiloxane nanoparticles as optical tracers
2007
Polyorganosiloxane microgels have been synthesized by polycondensation in a microemulsion of trimethoxysilanes. Highly crosslinked rather monodisperse particles of radius about 10 nm are obtained.