Effect Of Emulsifier Type Research Articles

Effect of Emulsifier Type on Droplet Disruption in Repeated Shirasu Porous Glass Membrane Homogenization

The influence of various emulsifier types (anionic, nonionic, and zwitterionic) on the mean particle size, transmembrane flux, and membrane fouling in repeated membrane homogenization using a Shirasu porous glass (SPG) membrane has been investigated. Oil-in-water (O/W) emulsions (40 wt % corn oil stabilized by 0.06-2 wt % sodium dodecyl sulfate (SDS) or 0.1-2 wt % Tween 20 at pH 3 or 0.5-2 wt % beta-lactoglobulin (beta-Lg) at pH 7) were prepared by passing coarsely emulsified feed mixtures five times through the membrane with a mean pore size of 8.0 microm under the transmembrane pressure of 100 kPa. The flux increased as the number of passes increased, tending to a maximum limiting value. The maximum flux for the Tween 20-stabilized emulsions (5-47 m3.m(-2).h(-1)) was smaller than that for the SDS-stabilized emulsions (29-60 m3.m(-2).h(-1)) because less energy was needed for the disruption of a SDS-stabilized droplet due to the lower interfacial tension. The mean particle size after five passes was 4.1-6.8 and 6.4-8.7 mum for 0.1-2 wt % SDS and Tween 20, respectively. The flux in the presence of beta-Lg was much smaller than that in the presence of SDS and Tween 20, which was a consequence of more pronounced membrane fouling, due to the protein adsorption to the membrane surface. After five passes through the membrane, the fouling resistance in the presence of 2 wt % beta-Lg (1.1 x 10(10) 1/m) was 2 orders of magnitude higher than that for 0.5 wt % Tween 20 and an order of magnitude higher than the membrane resistance. If a clean membrane was used in the fifth pass, a 2-fold reduction of the fouling resistance was observed.

Effect of emulsifier type, droplet size, and oil concentration on lipid oxidation in structured lipid-based oil-in-water emulsions

The effect of emulsifier type, droplet size, and oil concentration on lipid oxidation was determined for caprylic acid/canola oil structured lipid-based emulsions. Oil-in-water emulsion samples were prepared with sucrose fatty acid ester or whey protein isolate and 10 or 30% oil, and then homogenized at 1000 or 10,000 psi to form different particle sizes. The peroxide values, anisidine values, and TOTOX values of emulsions stored at 50 °C were measured over time. Decreasing oil concentrations led to an increase in total oxidation. Whey protein isolate had a significant antioxidant effect on the oxidation rates compared to sucrose fatty acid esters. Particles size had no effect on lipid oxidation in structured lipid-based oil-in-water emulsions.

Preparation and characterization of MMA-BA-DMAEMA terpolymer latex

The terpolymer latex of methyl methacrylate (MMA)/butyl acrylate (BA)/dimethylaminoethyl methacrylate (DMAEMA) was prepared by batch and semi-continuous emulsion copolymerization. The effects of emulsifier type and concentration, polymerization temperature, and feed policy of emulsified monomers on process stability of the copolymerization and properties of the terpolymer latex were studied systematically. The results suggest that the selection of emulsifier should not be based on the HLB values for the DMAEMA-containing systems. The co-emulsifiers suitable for stabilizing the copolymerization process are in the order of SDS/OP>SDBS/OP>OT/OP. The results also indicate that an increase in amount of the co-emulsifiers, sodium dodecyl sulfate (SDS) and octyl phenol polyoxyethyl ether (OP), improves the process stability, decreases the surface tension and particle size of latices; however, it has little influence on the electrolyte stability when SDS/OP ratio is unchanged. A decrease in reaction temperature improves the process stability of polymerization but decreases the electrolyte stability of latices. The DMAEMA content does not affect the process stability significantly under investigated conditions but contributes to improve the electrolyte stability of latices. Compared to the batch polymerization process, the semi-continuous polymerization with a lower monomer feed rate provides better process stability for the polymerization and better electrolyte stability for the latices.

Effect of emulsifier type on sensory properties of oil-in-water emulsions

This work investigates the fundamental properties of emulsifiers that may contribute to the fat-associated sensory attributes of emulsions. Model oil-in-water emulsions were prepared with 0, 12, 24, 36 and 48% oil and emulsified with seven different emulsifiers; two proteins; sodium caseinate and whey protein, and five different sucrose esters. Emulsions were rated for perceived ‘fat content’, ‘creaminess’ and ‘thickness’ on nine-point category scales. Instrumental measurements of particle size, viscosity, thin film drainage, surface dilational modulus and interfacial tension were made. The sensory results indicate significant main and interactive effects of fat level and emulsifier type. At higher fat levels, emulsions prepared with sodium caseinate and whey protein emulsifiers had higher viscosities and higher sensory scores than those prepared with the sucrose esters. Results indicate that emulsifier type has a significant effect on the sensory properties of oil-in-water emulsions, and relationships between instrumental and sensory measures suggest that this may be due to the interfacial properties of emulsifiers at the oil–water interface. © 1998 SCI.

Effect of emulsifier type and homogenization temperature and pressure on physical properties of peanut extract

SummaryPeanut extract (90.4% moisture, 3% protein and 4.5% fat, w/w) was homogenized using a two‐valve homogenizer and the effects of emulsifier and homogenization temperature and pressure on the physical properties were studied. Homogenization without emulsifier at 72°C increased the emulsion stability (ES) and sedimentation index (SI) by 5–11% and 15% respectively, compared to homogenization at 60°C. Homogenization with gum arabic increased the ES and viscosity by 17–22% and 127–176% respectively, and decreased SI by 26–38%. Homogenization with soya lecithin increased the ES and viscosity by 28–33% and 16–18% respectively, and decreased SI by 35–44%. Homogenization with Recodan EMS® (monodiglycerides + glycerol monostearates + soya lecithin) or Recodan CM® (monodiglycerides + glycerol monostearates + guar gum + carrageenan) increased the ES and colour lightness (L*) by 43–60% and 12% respectively, and decreased SI by 44–48%. Addition of Recodan CM® increased the viscosity by 482%. ES and L* increased with pressure. Extracts homogenized without emulsifier, with gum arabic, soya lecithin or Recodan EMS® were Newtonian whereas the extract homogenized with Recodan CM® was pseudoplastic.

Effect of Emulsifier Type on the Crystallization Kinetics of Oil-in-Water Emulsions Containing a Mixture of Solid and Liquid Droplets

Measurements of the ultrasonic velocity as a function of time (at 6.0°C) have been used to monitor the kinetics of crystallization of oil droplets in n -hexadecane-in-water emulsions containing a mixture of solid and liquid droplets. Crystallization is induced in liquid droplets when solid droplets are present. Induced crystallization is probably caused by crystals, protruding from solid droplets, penetrating into liquid droplets during collisions and thus acting as nucleation sites for crystal growth. The rate of induced crystallization depends strongly on the type of emulsifier used to stabilize the emulsion droplets. For the series of emulsifiers used in this study the rate decreased in the following order: Tween 20 > SDS > β-lactoglobulin > β-casein. Differences in rate can be explained by considering the influence the emulsifiers have on the interactions between droplets.

Effect of emulsifier type on the copolymerization of styrene and acrylic acid

AbstractIn this work we report the emulsion copolymerization of styrene and acrylic acid using a cationic (cetyltrimethylammonium bromide or CTAB) or an anionic (sodium dodecylsulfate or SDS) emulsifier. Latexes were stable and monodisperse with spherical particles of ∼100 nm for the CTAB latex and of ∼70 nm for the SDS latex. However, a random copolymer was produced with CTAB whereas a “blocky” copolymer was obtained with SDS. Here we propose a mechanism to explain these structural differences in terms of the relative reactivities of styrene and acrylic acid and of their initial location and distribution in the SDS and CTAB emulsions.

Encapsulation and Prolonged Release Behaviour of W/O/W Type Multiple Emulsions

AbstractW/O/W type multiple emulsions were prepared by two step emulsification procedures using an oily lymphographic agent, lipiodol, as an inner oil phase and Pluronic F‐68 as a hydrophilic emulsifier contained in the outer aqueous phase. Span 80, Pluronic L‐64 and HCO‐60 were used as emulsifiers incorporating them into the inner oil phase. The phase volume of the inner and outer aqueous phases and the yield of the w/o/w type multiple emulsions were studied. The dissolution behaviour of the w/o/w type multiple emulsions were determined by a dialysis method employing cellulose tubing. The effect of emulsifier type and the amount of HCO‐60 on the stability and prolonged release behavior of the w/o/w type multiple emulsions with or without lecithin, was also examined. The results indicate the HCO‐60 is a better emulsifier than Span 80 or Pluronic L‐64. Its use improves the stability and the prolonged release behavior of w/o/w type multiple emulsions.

Correlation Between Nature of Emulsifier and Multiple Emulsion Stability

AbstractThe effect of emulsifier type on the preparation and stability of multiple emulsions was studied. The influence on the yield of preparation and stability with regard to the HLB of emulsifier II was found to be different for each emulsifier. The best stabilities of the multiple emulsions were obtained when there is a similarity between the hydrophobic part of the emulsifier and the oil phase.