A Multiscale Investigation of Poria cocos Peel Crude Polysaccharides in Foams and Emulsions: From Molecular Features, Interfacial Properties to Emulsifier Performance

This study focused on the interfacial properties of Poria cocos peel crude polysaccharides (PCSCP) under different concentrations (0.0001%–0.1%, w/w), pH values (3.0–11.0), and ionic strengths (0–500 mM). The results showed that, with increasing PCSCP concentration, electrostatic repulsion gradually increased. At 0.1%, the absolute zeta potential (|ζ|) reached a maximum (35.3 mV) and particle size decreased to the minimum (156.7 nm), resulting in the highest interfacial pressures (π) at the air‐water and oil–water interfaces (35.31 and 16.80 mN/m, respectively). Meanwhile, interfacial film strength and emulsion viscosity increased, and 0.1% PCSCP exhibited superior emulsion and foam stability (ESI = 106.348 min, FS = 92.59%). pH also significantly affected PCSCP interfacial behavior. At pH 3.0, PCSCP showed the strongest electrostatic repulsion (|ζ| = 36.03 mV) and the smallest particle size (573.33 nm), giving outstanding air‐water and oil–water interfacial properties: π values of 36.96 and 16.64 mN/m, diffusion rates ( K diff ) of 0.604 and 0.220 mN/m/s −0.5 , and elastic moduli ( E d ) of 74.32 and 57.64 mN/m, respectively. These results were consistent with the best foaming performance (FA = 120.77%, FS = 78.35%) and emulsifying performance (EAI = 77.24 m 2 /g, ESI = 150.38 min). Notably, PCSCP showed interface‐dependent dual effects in Na + environments. Compared with the control, Na + accelerated PCSCP diffusion and enhanced interfacial film elasticity at the air‐water interface, significantly improving foaming performance. In contrast, Na + weakened oil–water interfacial construction by screening intermolecular electrostatic repulsion, thereby reducing emulsion stability. Overall, PCSCP shows strong potential as a clean‐label natural emulsifier and foam stabilizer.