Agar-lauric acid complex-stabilized Pickering emulsions: Fabrication, stabilization, and probiotics encapsulation

Abstract

Hydrophobic agar laurate small granules (AGLs) were fabricated with one-step dry ball milling. AGLs showed higher surface activity, accompanied by diminished surface and interfacial tensions compared to natural agar. AGLs exhibited an exceptional ability to stabilize high internal phase emulsions (HIPEs), requiring merely a 1% particle concentration. Laser confocal and cryo-scanning electron microscopy demonstrated that the stability of the emulsions was maintained by a three-dimensional network formed by the AGLs self-assembling and particle adsorption collectively. In emulsions with low oil content, AGLs particles adsorbed onto the droplet surfaces formed a barrier, and some particles formed a dense network structure in the aqueous phase, restricting droplet movement. As oil content increased, the droplets were in close proximity to one another and formed a bridging structure composed of HIPEs, with the spaces between the droplets forming a continuous network in which the droplets were embedded. These emulsions showed good stability under alkaline conditions, NaCl concentration not exceeding 150 mM, and temperature below 90 °C. In vitro gastrointestinal digestion simulations demonstrated that Pickering HIPEs stabilized by AGLs can serve as delivery vehicles for probiotics, protecting them from damage in the digestive environment and considerably increasing the total number of viable cells. AGLs can be used as a safe and effective Pickering emulsifier, and the Pickering HIPEs have promising applications as delivery vehicles in the food and pharmaceutical industries.