Pea protein-steviol glycosides complexes: Fabrication, characterization and evaluation for the emulsifying capacity

Mixtures of pea protein isolate (PPI, 2%) and steviol glycosides (STE, 0.1% ∼ 1%) were prepared, characterized, and assessed for emulsifying ability. Critical micelle concentration of STE increased from 0.49% (pure STE) to 0.60% (PPI-STE complex). Molecular docking and fourier transform infrared spectroscopy showed that hydrophobic interactions and hydrogen bonds drove complexation. STE above 0.6% significantly increased complex surface hydrophobicity and altered PPI tertiary/secondary structure (reduced α-helix, increased β-sheet). Incorporation of STE reduced the interfacial tension of PPI and decreased the number of adsorbed proteins at the interface with the great change happened above 0.6%. Emulsions with PPI-STE had decreased particle size and increased zeta potential (up to 0.6% STE), exhibiting enhanced stability against ionic strength (100-300 mM NaCl), pH (3-7), and storage (28 days at 4 °C). These findings highlight the potential of PPI-STE complexes especially with STE above the critical micelle concentration as natural, high-performance emulsifiers for sustainable food applications.