Food-grade shellac–ethyl cellulose Janus-like nanoparticles: Formation mechanism and anisotropy-mediated interfacial behavior

Food-grade particles capable of efficient interfacial adsorption and robust interfacial layer formation are highly desirable for stabilizing multiphase food colloids. In this study, shellac–ethyl cellulose Janus-like nanoparticles (SL–EC JLN) were fabricated by flash nanoprecipitation and systematically characterized in terms of their structure, physicochemical properties, stability and oil–water interfacial behavior. FE-SEM revealed the presence of dumbbell-like particles with anisotropic features, while FTIR, DSC and TGA analyses further distinguished the SL–EC JLN from the single-component nanoparticles (SLN, ECN) and their physical mixture (ECN + SLN). Compared with SLN, ECN, and ECN + SLN, the SL–EC JLN exhibited superior physical stability during storage. In addition, the SL–EC JLN remained stable under pH, ionic strength, and thermal stresses. At the oil–water interface, SL–EC JLN exhibited enhanced adsorption kinetics and interfacial reorganization, as reflected by the lowest quasi-equilibrium interfacial tension and higher diffusion, penetration, and rearrangement rate constants. The SL–EC JLN displayed more pronounced frequency dependence of the interfacial dilatational modulus and more regular nonlinear stress–deformation loops, suggesting a more coordinated interfacial organization with greater adaptability to large-amplitude deformation. These findings suggest that the co-assembled SL–EC Janus-like particle architecture contributes to improved colloidal stability and interfacial regulation, providing a basis for the rational design of food-grade anisotropic particles for advanced interfacial engineering.