Non-covalent interaction between soybean protein isolate and naringenin: Focused on binding mechanism, interface behavior, and functional properties

In this study, non-covalent complexes of soybean protein isolate (SPI)- Naringenin (Nar) with different concentrations of Nar were prepared, and their binding mechanisms and interfacial properties were investigated. The results showed that the content of α-helix and β-sheet in the SPI-Nar complex decreased to 19.62% and 26.58%, respectively. With an increase in Nar concentration, there was an increase in the ultraviolet absorption peak and a decrease in fluorescence emission intensity. Fluorescence quenching analysis revealed static quenching between Nar and SPI, with a binding site of 0.98, ΔG, ΔH, and ΔS had negative values. Molecular docking and molecular dynamics simulations indicated that Nar binds within the hydrophobic cavity of SPI. At a Nar addition amount of 1 mg/mL, the EAI and ESI of the SPI-Nar complex were 91.97 m 2 /g and 49.28 min, respectively. The foaming capacity and foam stability were 58.0% and 62.07%, respectively, and exhibited optimal air/water interfacial properties. The functional properties of the non-covalent complex were effectively improved, providing a theoretical basis for its application in the food industry. • Soybean protein isolate (SPI)-naringenin (Nar) non-covalent complex was prepared. • The non-covalent binding mechanism of SPI and Nar was investigated. • Nar has improved the air/water interface and foaming properties of SPI.