Formation and Stabilization of W₁/O/W₂ Emulsions with Gelled Lipid Phases

Water-in-oil-in-water (W₁/O/W₂) emulsions are emulsion-based systems where the dispersed phase is an emulsion itself, offering great potential for the encapsulation of hydrophilic bioactive compounds. However, their formation and stabilization is still a challenge mainly due to water migration, which could be reduced by lipid phase gelation. This study aimed to assess the impact of lipid phase state being liquid or gelled using glyceryl stearate (GS) at 1% (w/w) as well as the hydrophilic emulsifier (T80: Tween 80 or lecithin) and the oil type (MCT:medium chain triglyceride or corn oil (CO) as long chain triglyceride) on the formation and stabilization of chlorophyllin W₁/O/W₂ emulsions. Their colloidal stability against temperature and light exposure conditions was evaluated. Gelling both lipid phases (MCT and CO) rendered smaller W₁ droplets during the first emulsification step, followed by formation of W₁/O/W₂ emulsions with smaller W₁/O droplet size and more stable against clarification. The stability of W₁/O/W₂ emulsions was sensitive to a temperature increase, which might be related to the lower gelling degree of the lipid phase at higher temperatures. This study provides valuable insight for the formation and stabilization of W₁/O/W₂ emulsions with gelled lipid phases as delivery systems of hydrophilic bioactive compounds under common food storage conditions.