Effect of polysaccharide emulsifiers on the fabrication of monodisperse oil-in-water emulsions using the microchannel emulsification method

The microchannel emulsification method was used to prepare monodisperse soybean oil-in-water emulsions, with polysaccharides as the sole emulsifier. The effects of different types (sodium alginate, carboxymethyl cellulose, pectin, gum arabic) and concentrations (0.1, 0.5, 1.0%) of polysaccharide on the droplet size, droplet size distribution and stability of the emulsions were investigated. The droplet diameters of the resulting emulsions were in the range of 35 ± 2 to 47 ± 3 μm, with coefficient of variations (CV) of below 6.6%. Generally, the droplet size increased as the concentration of the polysaccharides increased. The stability of emulsions prepared using 0.5% of sodium alginate, carboxymethyl cellulose and gum arabic was also evaluated in situ. Sodium alginate- and gum arabic-stabilized emulsions were stable for at least 6 h

Biosurfactants for Microbubble Preparation and Application

Biosurfactants can be classified by their chemical composition and their origin. This review briefly describes various classes of biosurfactants based on their origin and introduces a few of the most widely used biosurfactants. The current status and future trends in biosurfactant production are discussed, with an emphasis on those derived from plants. Following a brief introduction of the properties of microbubbles, recent progress in the application of microbubble technology to molecular imaging, wastewater treatment, and aerobic fermentation are presented. Several studies on the preparation, characterization and applications of biosurfactant-based microbubbles are reviewed

Effect of dispersed phase viscosity on maximum droplet generation frequency in microchannel emulsification using asymmetric straight-through channels

Effect of dispersed phase viscosity on maximum droplet generation frequency in microchannel emulsification using asymmetric straight-through channel

Rapid generation of highly uniform droplets using asymmetric microchannels fabricated on a single crystal silicon plate

A microfluidic device can be identified by the fact that it has one or more channels with at least one dimension less than 1 mm. The most common types of microfluidic devices are: (i) soft microfluidic devices fabricated in elastomeric materials such as PDMS by soft lithography [1], (ii) glass devices manufactured in quartz glass or glassy polymers such as PMMA by etching or micromachining [2], and (iii) microchannel (MC) array devices fabricated in silicon by photolithography and wet-etching or deep-reactive ion etching processing [3]. Microfluidic devices can be used for capillary electrophoresis [4], liquid-liquid extraction [5], immunoassays [6], cellomics [7], proteomics [8], DNA analysis [9], blood rheology measurements [10], microreactors [11], droplet formation [2], etc. The soft microfluidic devices such as T-junctions and flow focusing devices are suitable for rapid generation of monodispersed droplets with a coefficient of variation (CV) in a dripping regime of generally less than 3 %. Although the frequency of drop production can be as high as 7000 Hz, the overall productivity in terms of volume flow rate of the disperse phase is very low because the droplets are formed from a single channel. Silicon MC array devices are much more suitable for large-scale applications because the total number of microchannels on a chip can be hundreds of thousands. The aim of this work was to investigate the generation of uniform droplets at high production rates using novel asymmetric MC array microfabricated on a silicon plate [12]. Monodispersed emulsion droplets are much more favourable both in fundamental studies and practical applications. Emulsion appearance and rheology, stability against Oswald ripening and creaming, and the suitability of droplets as templates to the production of solid micro- and nano-particles are strongly influenced by their particle size distribution

Microchannel emulsification

Microchannel emulsificatio

Generation of highly uniform droplets using asymmetric microchannels fabricated on a single crystal silicon plate: effect of emulsifier and oil types

Uniform droplets of soybean oil, MCT (medium-chain fatty acid triglyceride) oil and n-tetradecane with a mean diameter of 26–29 μm have been generated using asilicon 24 × 24 mm microchip consisting of 23,489 asymmetric microchannels fabricated by photolitography and deep-reactive ion etching. Each microchannel consisted of a circular 10-μm diameter straight hole with a length of 70 μm and a 50 × 10 μm rectangular microslot with a depth of 30 μm. At the constant oil flux of 10 L m− 2 h− 1, the percent of active channels increased with increasing the oil viscosity and ranged from 4% for n-tetradecane to 48% for soybean oil. The size distribution span for SDS (sodium dodecyl sulphate)- and Tween 20 (polyoxyethylene (20) sorbitan monolaurate)-stabilized soybean and MCT oildroplets was 0.21–022. The ability of asymmetricmicrochannels to generate monodisperse soybean oildroplets at the very low SDS concentration of 0.01 wt.% has been demonstrated. At the SDS concentration below the CMC, the generated droplets tend to attach to the plate surface, whereas at the higher SDS concentration they detach from the plate as soon as they are formed. The agreement between the experimental and CFD (Computational Fluid Dynamics) simulation results was excellent for soybean oil and the poorest for n-tetradecane

Manufacture of monodisperse oil-in-water emulsions at high droplet formation rates using novel asymmetric silicon microchannels

Manufacture of monodisperse oil-in-water emulsions at high droplet formation rates using novel asymmetric silicon microchannel

Production of uniformly sized emulsion drops at high production rates using asymmetric micro channel plates

The purpose of this work was to investigate maximum disperse phase flux required for production of monodisperse drops in a straight-through microchannel (MC) array device. The experiments have been carried out using single-crystal silicon MC plate consisting of about 23,000 asymmetric MCs fabricated by photolithography and deep reactive ion etching (DRIE). Each MC consisted of a rectangular 50×10 μm slot and a circular 10 μm-diameter hole in the middle of each slot. A depth of the hole was 70 μm and the slot depth was 30 μm. The dispersed phase was soybean oil, MCT (middle-chain fatty acid triglyceride) oil and n-tetradecane with a viscosity at 293 K of 50, 20, and 2.7 mPa·s, respectively. The continuous phase was 2 wt% Tween 20 or SDS. (Continues...)

β-Carotene nanodispersions: preparation, characterization and stability evaluation

The aim of the present study was to investigate the preparation of β-carotene nanodispersions as potential active ingredients for food formulations. Nanodispersions containing β-carotene were obtained by a process based on an emulsification–evaporation technique. The preparation method consisted of emulsifying an organic solution of β-carotene in an aqueous solution containing emulsifier using two different homogenizers (a conventional homogenizer and a microfluidizer), followed by direct solvent evaporation under reduced pressure. The influence of different homogenizing conditions (pressure and cycle) and two organic/aqueous phase ratios on particle size parameters and content of β-carotene was investigated. In addition, the stability of β-carotene nanodispersions was carried out at a storage temperature of 4 °C. The particle size distribution of β-carotene in nanodispersions was demonstrated with a laser diffraction particle size analyzer and the retention of β-carotene in the prepared nanodispersions was studied by high-pressure liquid chromatography. In general, homogenization pressure and cycle had significant (P < 0.05) effects on various particle size parameters. A volume-weighted mean diameter (D4,3) of β-carotene nanoparticles, ranging from 60 to 140 nm, was observed in this study