Tunable kafirin nanoparticles at oil-water interfaces: interfacial assembly and emulsion stabilization

Pickering emulsions are stabilized by particles adsorbed at oil–water interfaces and are increasingly explored as alternatives to conventional surfactants in food systems. Kafirin, a major prolamin of sorghum that shares high homology with the well-studied maize protein zein, can self-assemble into nanoparticles and act as a Pickering stabilizer. However, the interfacial assembly and emulsion stabilization properties of these prolamin nanoparticles remain poorly understood, which limits their broader application. Due to their high surface hydrophobicity, the interfacial behavior of kafirin nanoparticles largely depends on their physicochemical properties, particle-oil interactions, and in-plane particle-particle interactions. A clear understanding of how these factors affect interfacial assembly and emulsifying properties is still lacking. This thesis answers questions regarding the effects of wettability, bioactive distribution, and oil polarity on the interfacial mechanical properties and emulsion stabilization properties of kafirin-based nanoparticles. The results provide guidance for the rational design of plant-protein-based Pickering stabilizers for bioactive encapsulation and colloidal delivery applications.