Stable, food-grade water-in-oil-in-water double emulsions (DEs) were designed for possible controlled release applications in foods.
The primary water-in-oil emulsion prepared with water, canola oil, polyglycerol polyricinoleate (PgPr), sodium chloride (NaCl) and gelatin was stable for months. DEs were developed by dispersing the primary emulsion into a continuous aqueous phase containing different hydrophilic emulsifiers and stabilizers, such as sodium caseinate, gum arabic, polysorbate 80, sodium alginate, and poloxamer 188. Combinations of polysorbate 80 with polysaccharides (gum arabic or sodium alginate) were also investigated.
Stability of DEs was observed macroscopically via sedimentation tests whereas microstructure were examined using light microscopy. Polysorbate 80 was the most suitable hydrophilic emulsifier for obtaining stable DEs. A hypertonic internal aqueous phase resulted in increased emulsion stability.
Given their long-term kinetic stability, such DEs may potentially be used as controlled release matrices or texture modifiers in foods.
