Engineering functional alginate beads for encapsulation of Pickering emulsions stabilized by colloidal particles

Pickering emulsions are widely used as delivery systems in food, cosmetics, and pharmaceutical industries for the encapsulation and sustained release of hydrophilic compounds. The solid colloidal particles stabilized in oil–water interface can prevent the oil droplets from undesired coalescence and endow additional functionality. In order to impact further protection and pH-responsive deliver of the encapsulated component, we used two kinds of mechanisms. For internal interaction, the excess Ca2+ on the surface of zein–tannic acid (TA)/Ca2+ nanoparticles (NPs) interacted with alginate added to form a second layer. In the case of external gelation, a cross-linking agent (Ca2+) was dissolved in the aqueous gelling bath outside. When added the mixture of the emulsions to Ca2+ solution, alginate–Ca beads were formed to encapsulate the emulsions and further impact the pH-responsive deliver of VD3 in stomach and rapid release of it in small intestine.