Search results for "Colloid"
showing 10 items of 1288 documents
Molecule structural factors influencing the loading of flavoring compounds in a natural-preformed capsule: Yeast cells
2016
International audience; Yeast cells are efficient microcapsules for the encapsulation of flavoring compounds. However, as they are preformed capsules, they have to be loaded with the active. Encapsulation efficiency is to a certain level correlated with LogP. In this study, the effect of structural factors on the encapsulation of amphiphilic flavors was investigated. Homological series of carboxylic acids, ethyl esters, lactones, alcohols and ketones were encapsulated into the yeast Yarrowia lipolytica. Although, in a single homological series, the length of the molecule and thus the LogP were correlated with encapsulation efficiency (EY%), big differences were observable between series. Fo…
Monitoring of transglutaminase crosslinking reaction by 1H NMR spectroscopy on model substrates
2015
International audience; A new method based on 1H NMR spectroscopy was developed for monitoring transglutaminase crosslinking reaction with model molecules (CBZ-Gln-Gly and N-α-acetyl-lysine). The transglutaminase reaction led to the appearance of new resonances on NMR spectrum as well as significant decrease in others. The new observed resonances, originated from newly formed ɛ-(γ-glutamyl)lysine isopeptide bonds, evidence the enzymatic reaction and allow to quantify the ɛ-(γ-glutamyl)lysine fragment. Moreover, the decrease in resonance intensity, originated from lysine, permit to determine the crosslinking degree. These results obtained by 1H NMR spectroscopy can be used as an alternative …
Pulsed electric field and pH assisted selective extraction of intracellular components from microalgae Nannochloropsis
2015
Abstract The study was aimed at investigation of the potential of pulsed electric field (PEF) pre-treatment as a preliminary step of pH-assisted aqueous extraction of algae components from microalgae Nannochloropsis suspensions. The PEF and sonication (S) were compared as pretreatment methods. They were applied at normal (pH = 8.5) and basic (pH = 11) conditions, and supplementary basic extraction (at pH = 11) was done. The extracts were analyzed for content of pigments, proteins, carbohydrates, total phenolic compounds and antioxidant capacity. The colloidal stability of PEF- and S-pretreated suspensions was also evaluated. The data evidence that PEF technique allows selective extraction o…
Cellulose ether emulsions as fat source in cocoa creams: Thermorheological properties (flow and viscoelasticity)
2019
Flow behaviour and viscoelastic properties at three different temperatures (20, 45 and 70 °C) of cocoa filling creams have been studied. These creams were composed of cocoa, starch, sugar, skimmed milk powder and non-digestible cellulose ether emulsions as fat source. Two types of methylcelluloses, MC, and two types of hydroxypropyl methylcelluloses, HPMC, with different chemical substitution degrees were employed. Results showed important differences in zero shear viscosity and shear thinning character at room temperature, due to the different internal structure revealed by the viscoelastic moduli spectra. Temperature sweeps of storage modulus showed different temperature gelation dependin…
Effect of Metal Complexation on the Conductance of Single-Molecular Wires Measured at Room Temperature
2014
The present work aims to give insight into the effect that metal coordination has on the room-temperature conductance of molecular wires. For that purpose, we have designed a family of rigid, highly conductive ligands functionalized with different terminations (acetylthiols, pyridines, and ethynyl groups), in which the conformational changes induced by metal coordination are negligible. The single-molecule conductance features of this series of molecular wires and their corresponding Cu(I) complexes have been measured in break-junction setups at room temperature. Experimental and theoretical data show that no matter the anchoring group, in all cases metal coordination leads to a shift towar…
Liquid Crystal Phases in Suspensions of Charged Plate-Like Particles
2012
International audience; Anisotropic interactions in colloidal suspensions have recently emerged as a route for the design of new soft materials. Nonisotropic particles can form nematic, smectic, hexatic, and columnar liquid crystals. Although the formation of these phases is well rationalized when excluded volume is solely at play, the role of electrostatic interactions still remains unclear and even less so when particles present a charge heterogeneity, for example, clays. Here, we use Monte Carlo simulations of concentrated suspensions of charged disk-like particles to reveal the role of Coulomb interactions and charge anisotropy underlying liquid crystal formation and structures. We obse…
Embryonic Growth of Face-Center-Cubic Silver Nanoclusters Shaped in Nearly Perfect Half-Cubes and Cubes.
2016
Demonstrated herein are the preparation and crystallographic characterization of the family of fcc silver nanoclusters from Nichol’s cube to Rubik’s cube and beyond via ligand-control (thiolates and phosphines in this case). The basic building block is our previously reported fcc cluster [Ag14(SPhF2)12(PPh3)8] (1). The metal frameworks of [Ag38(SPhF2)26(PR′3)8] (22) and [Ag63(SPhF2)36(PR′3)8]+ (23), where HSPhF2 = 3,4-difluorothiophenol and R′ = alkyl/aryl, are composed of 2 × 2 = 4 and 2 × 2 × 2 = 8 metal cubes of 1, respectively. All serial clusters share similar surface structural features. The thiolate ligands cap the six faces and the 12 edges of the cube (or half cube) while the phosp…
Plasmonic nanosensors reveal a height dependence of MinDE protein oscillations on membrane features
2018
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Photoexcitation of the P4480 State Induces a Secondary Photocycle That Potentially Desensitizes Channelrhodopsin-2
2018
Channelrhodopsins (ChRs) are light-gated cation channels. In spite of their wide use to activate neurons with light, the photocurrents of ChRs rapidly decay in intensity under both continuous illum...
A novel ultradeformable liposomes of Naringin for anti-inflammatory therapy
2018
[EN] Ultradeformable liposomes were formulated using naringin (NA), a flavanone glycoside, at different concentrations (3, 6 and 9 mg/mL). Nanovesicles were small size (similar to 100 nm), regardless of the NA concentration used, and monodisperse (PI<0.30). All formulations showed a high entrapment efficiency (similar to 88%) and a highly negative zeta potential (around -30 mV). The selected formulations were highly biocompatible as confirmed by in vitro studies using 3T3 fibroblasts. In vitro assay showed that the amounts (%) of NA accumulated in the epidermis (similar to 10%) could explain the anti-inflammatory properties of ultradeformable liposomes. In vivo studies confirmed the higher …