Tailoring W/O emulsions for application as inner phase of W/O/W emulsions: Modulation of the aqueous phase composition

摘要

This work focused on evaluating the effect of adding sodium chloride (0.2% w/w NaCl), gallic acid (0.5% w/w GA) or GA/NaCl (0.5%/0.2% w/w) blend, as well as PGPR concentration (1.5-4.5% w/w) on the stability and structure of water-in-oil (W/O) emulsions aiming their application as an internal phase of water-in-oil-in-water (W/O/W) emulsions. The GA/NaCl and water (control) systems showed similar interfacial tension curves, but the addition of GA or NaCl promoted a remarkable reduction in the interfacial tension. The presence of GA and/or NaCl promoted subtle changes in interface viscoelasticity, showing that interface properties were mostly impacted by PGPR. All emulsions showed Newtonian behavior, but kinetic stability was improved in the presence of NaCl (NaCl or GA/NaCl) and in the highest PGPR concentration. In addition to good stability, the GA/NaCl system stabilized by 4.5% PGPR can present functional properties, due to the presence of GA, which makes this system a promising alternative to produce double emulsions with a wider application.