Mechanism and Influential Factors of the Stability of Hydrophobic Starch Pickering Emulsion Gels

Abstract

This study aimed to investigate the effects of different factors (temperature, pH and ionic strength) on the stability of Pickering emulsion gel stabilized by starch-lipid complexes (SFAC) and uncover the underlying mechanism. The results of observation using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) showed that SFAC particles could be adsorbed onto the oil-water interface, forming a tight barrier to wrap the dispersed oil droplets, leading to the formation of round emulsion droplets. The close packing of the emulsion droplets resulted in the formation of a stable gel network structure. Optical microscopic observation and analysis of particle size distribution and zeta potential showed that the hydrophobic starch emulsion gel maintained its structure and exhibited good storage stability at pH 3–9 and 0.1–0.9 mol/L ionic strength. In addition, the Pickering emulsion gel was thermally reversible; the particle size increased, the viscosity decreased and the gel melted at high temperatures, and the melted sample gelled again upon cooling. These results showed that hydrophobic starch Pickering emulsion gels are highly stable over a wide range of temperature, pH and ionic strength, and are suitable for the stabilization of different vegetable oils.

Keywords

• starch-fatty acid complex; pickering emulsion gel; oleogel; structuring oil