Hydrophobically modified dextrans as stabilizers for O/W highly concentrated emulsions. Comparison with commercial non-ionic polymeric stabilizers

Abstract

Two amphiphilic polysaccharides derived from a nonionic bacterial polysaccharide of dextran (DexP10 and DexP15) have been explored as emulsifiers for preparing highly concentrated oil-in-water emulsions in a semibatch (two-step) process. A fixed amount of stabilizer (10 g/L of emulsion) was employed for preparing emulsions at dispersed-phase volumetric fractions ranging from 0.850 to 0.938. Their performances as stabilizers (interfacial tension, kinetics, droplet size distribution, rheological behavior and stability) were evaluated and compared with a group of four ABA non-ionic commercial stabilizers from Pluronic series (F68, F127, P105 and L64) and a low-molecular-weight surfactant (Tween 80). Our results demonstrate these ABn graft amphiphilic polysaccharides can be promising stabilizers as efficient as commercial non-ionic polymeric stabilizers for preparing highly concentrated emulsions in spite of lower interfacial tensions, slower kinetics, or showing emulsions a larger droplet size and less monodispersity.