Sequence-dependent assembly of whey protein‑sodium alginate-steviol glycoside ternary complexes: Mechanistic insights...

This study aimed to elucidate the role of reaction sequence in modulating the assembly mechanism and functional performance of ternary complexes. Whey protein isolate (WPI), a widely used natural surfactant, exhibits environmental sensitivity and slow interfacial adsorption limitations. To address this, ternary complexes of WPI, sodium alginate (SA), and steviol glycosides (stevioside: rebaudioside A = 7:3) (STG) were constructed through sequence-controlled assembly. Molecular docking revealed a strong binding affinity between WPI and STG/SA via hydrogen bonding and hydrophobic interactions. Multispectral analysis showed that the binding of SA and STG in WPI was affected by different addition orders. The amount of beta folding increased, indicating a more flexible protein structure. The emulsifying stability index (ESI) of the WSG complex was the highest (768.16 min). These findings provide a blueprint for designing natural Pickering stabilizers tailored for acidic food matrices.