The role of alginate in starch nanocrystals-stabilized Pickering emulsions: From physical stability and microstructure to rheology behavior

Sodium alginate (SA) was used as a co-stabilizer to improve the Pickering emulsions stabilized by starch nanocrystals (SNC). Compared with pure SNC, SNC/SA complexes possess better neutral wettability with the contact angle approaching to 90°, more surface negative charges, and lower oil-water interfacial tension. These properties of particles make as-prepared emulsion higher stability with the lower creaming index and average droplet size. Furthermore, the emulsion exhibited good stability against salt (0-600 mM) and pH (2.0-6.0) at higher SA concentration (1.0 wt%). Confocal laser scanning microscopy (CLSM) images proved that SNC could be effectively adsorbed at the oil-water interface with the aid of SA. Rheological analysis showed that higher content of SA resulted in improved strength and higher viscosity of emulsion system. Results from this work indicating that SA could be a useful co-stabilizer to fulfill the demands of Pickering emulsions stabilized by SNC with stable characteristics.