Regulation of Whey Protein Microparticle Adsorption and Interfacial Film Formation by Polysaccharides for Enhanced Pickering Emulsion Stability

Abstract

The incorporation of polysaccharides into Pickering emulsions (PEs) has emerged as a novel strategy for enhancing emulsion stability. This study focuses on the impact of polysaccharide type and concentration on the colloidal particle behavior at interface and how these polysaccharide-regulated interfacial film properties affect PEs stability. PEs were prepared by mixing whey protein microparticles (WPM) with various concentrations of κ-carrageenan and guar gum. The results showed that at low concentrations, the lower viscosity of κ-carrageenan and guar gum facilitated the initial diffusion and penetration of WPM at the interface. However, the low interfacial protein content at this stage was insufficient to form a stable interfacial film. As concentration increased, both polysaccharides significantly restricted the diffusion and penetration of WPM. Notably, κ-carrageenan, with its high negative charge and double-helix structure, induced significant rearrangement of WPM (KR from -32.9×10-4 s -1 to -49.3×10-4 s -1), creating a dense, flexible interfacial film that improved emulsion stability. In contrast, guar gum, with its high molecular weight and nonionic nature, promoted the maintenance of particle conformation (KR value of -28.7×10-4 s -1, significantly lower than the pure protein particle group), forming strong interfacial films with high particulate density. Despite κ-carrageenan’s ability to enhance initial stability, its deformation reduced long-term stability compared to the guar gum system. Thus, polysaccharide type and concentration play a crucial role in regulating WPM interfacial adsorption and the resulting film rheology, providing key insights into the role of polysaccharides in optimizing interfacial properties and enhancing the stability of PEs.