Characterization of different double-emulsion formulations based on food-grade emulsifiers and stabilizers

This study focused on the preparation and characterization of water-in-oil-in-water (W1/O/W2)-type double emulsions designed by food-grade emulsifiers and stabilizers. The primary objective of this study was to compare different emulsion formulations in terms of droplet size, rheology, and stability and to reduce the amount of polyglycerol poliricinoleate (PGPR). To achieve these goals, PGPR and a PGPR–lecithin blend were utilized in the formation of the primary phase (W1/O), while varying concentrations of guar gum (GG) and gum tragacanth (GT) incorporated in the secondary water phase (W2). Shear thinning behavior was observed for all emulsion formulations. Sauter mean diameters of the emulsions prepared with PGPR as a hydrophobic emulsifier ranged between 30 µm and 75 µm, while those prepared with the PGPR–lecithin blend varied between 25 µm and 85 µm based on the first day's measurements. In emulsions with the PGPR–lecithin blend, the smallest droplet size was obtained when the GG–GT blend was incorporated in the external aqueous phase. Moreover, GG–GT blends had high consistency coefficients and high apparent viscosity values. It was also observed that PGPR–lecithin containing emulsions were more stable.