Formation and properties of zein Particle-GMS Co-stabilized pickering emulsions: Insights into the complex interface

Abstract

The interplay between colloidal particles and surfactant co-adsorption plays a pivotal role in determining interface properties and emulsion stability. This study delves into the influence of the Zp/GMS ratio on the physical stability of Zein particle-GMS co-stabilized emulsions (CPEs) and how co-adsorption and interfacial interactions impact this stability. Results indicated that the preferential adsorption of GMS facilitated the diffusion (Kdiff increased from 0.083 mNm−1 s−0.5 to 0.206 mNm−1 s−0.5) and penetration of Zp (KP increased from −17.0 × 104 s−1 to −23.6 × 104 s−1), triggering interface rearrangement. Consequently, intricate interfaces formed, inducing a synergistic reduction in interfacial tension. Moreover, the decreased Zp/GMS ratio bolstered the lateral molecular interactions between Zp and GMS at the interface, while also enhancing the longitudinal relaxation of GMS during interface deformation. Therefore, the Zp/GMS ratio played a pivotal role in controlling the stiffness, elasticity, and deformability recovery of complex interfaces in both lateral and longitudinal dimensions. Furthermore, in both O/W and W/O CPEs, a decreased Zp/GMS ratio improved the physical stability of CPEs by reducing the rate of droplet coalescence. To summarize, the enhanced stability of CPEs can be attributed to the reduction in droplet aggregation. This reduction is influenced by a combination of improved mechanical properties resulting from lateral molecular interactions at the interface and enhanced deformability recovery due to the longitudinal relaxation of GMS. These findings not only deepen our understanding of particle-surfactant interactions in Pickering emulsions but also pave the way for formulating emulsions with specific textures and stabilities.