Influence of gelation of internal aqueous phase on in vitro controlled release of W1/O/W2 double emulsions-filled alginate hydrogel beads

Abstract

κ-Carrageenan and locust bean gum (κ-C/LBG) were used as gelling polymers in the internal aqueous phase to prepare W 1 /O/W 2 double emulsions-filled alginate hydrogel beads. Rheological studies demonstrated the significant difference in the physical state and gel strength of internal aqueous phase samples prepared with various amounts of κ-C/LBG (0.5–2.0%). The results of microscopy, light scattering, and flow cytometry suggested that double emulsions gelled by 2.0% κ-C/LBG could effectively resist the oil droplets flocculation and W 1 -droplets coalescence, and delayed the release of the W 1 droplets, leading to smaller changes in the microstructure and droplets size. Furthermore, a slow or controlled release of tartrazine was reached during the in vitro intestinal digestion at high concentrations of κ-C/LBG. These findings point to possible applications for structuring W 1 /O/W 2 double emulsions with different physical properties of the gelled internal aqueous phases to achieve the controlled release of loaded hydrophilic compounds. • Internal aqueous phases were gelled by κ-carrageenan and locust bean gum. • Rheological properties difference of internal aqueous phase samples were investigated. • Digestion behavior of incorporated double emulsions with gelled W 1 droplets was illuminated. • Resist breakdown of double emulsions occurred during digestion. • Controlled release of encapsulated hydrophilic compounds was demonstrated.