title: Effect of emulsifier type on droplet disruption in repeated shirasu porous glass membrane homogenization.
abstract: 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.
authors.affiliation: Institute of Food Technology and Biochemistry, Faculty of Agriculture, University of Belgrade, P.O. Box 127, YU-11081 Belgrade-Zemun, Serbia & Montenegro. gtvladis@afrodita.rcub.bg.ac.yu
authors.forename: Goran T
authors.initials: GT
authors.lastname: Vladisavljević
authors.forename: Jeonghee
authors.initials: J
authors.lastname: Surh
authors.forename: Julian D
authors.initials: JD
authors.lastname: McClements
mesh_terms: D002627:Chemistry, Physical / Q000295:instrumentation / Q000379:methods; D004655:Emulsions / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D010316:Particle Size; D016062:Porosity; D013501:Surface-Active Agents / Q000737:chemistry*; D014783:Viscosity
chemical_list: D004655:Emulsions; D013501:Surface-Active Agents