2017 Volume 18 Issue 2 Pages 103-111
We investigated the factors affecting preparation of water-in-oil (W/O) emulsions using olive oil as the continuous phase, based on direct observation of microchannel (MC) emulsification.
Monodisperse droplets were produced using polyglycerin polycondensed ricinoleic acid ester (PGPR) as an emulsifier. The mean droplet diameter and the time required for droplet formation (droplet detachment time) increased with increased viscosity of the continuous phase. Emulsifier concentration affects droplet formation, and stable emulsification was observed at PGPR concentrations exceeding 1wt％. Adsorption of PGPR was analyzed based on interfacial tension measurement with different measurement time scales. Monodisperse droplets with mean droplet diameters of 24 µm to 90 µm and coefficients of variation below 7％ could be produced using MC plates having different MC geometries. Furthermore, we demonstrated that droplet formation behavior differed with the addition of milk components (skimmed milk powder and whey powder) to the dispersed phase, based on high-speed observation of individual droplet formation.
