Stabilization of oil-water interface by non-interfacial adsorbed native starch granules using depletion attraction

Abstract

The potential applications of emulsion systems prepared from solid particles are limitless across various fields. The emulsion, also known as Pickering emulsion, is constrained by the properties of the particles. An emulsion system prepared directly from unmodified, hydrophilic, natural starch granules was reported in the study. While the microstructure of this emulsion resembled that of Pickering emulsions, its formation mechanism was entirely different. The formation of the emulsion was governed by depletion attraction between hydrophilic polymers (Carboxymethyl cellulose, CMC) and amaranth starch granules. The microstructure and interfacial results revealed that the adsorption of starch granules at the oil-water interface was facilitated by depletion attraction induced by CMC, while their desorption was inhibited. Stability was maintained even at high oil volume fractions of up to 70%. The strength of depletion attraction in the emulsion could be controlled by varying the concentration of starch granules (3–7 w/v%), CMC (0.5–1.5 wt%), and the molecular weight of CMC, thus adjusting the microstructure and rheological properties of the emulsion. This technique could be widely applied to nature food particle, offering a new avenue for designing and manufacturing stable edible emulsion systems.