Pea protein based nanocarriers for lipophilic polyphenols: Spectroscopic analysis, characterization, chemical...

The current research aims to construct and assess pea protein isolate (PPI) nanocarriers for lipophilic polyphenols of curcumin (CUR), quercetin (QUE) and resveratrol (RES), respectively. Fluorescence analysis demonstrated that the binding affinity declined in sequence of QUE > CUR > RES and about one polyphenol compound was bound to protein. Thermodynamic parameters revealed that hydrophobic interaction was mainly responsible for complexation between CUR/RES and PPI, while hydrogen bonding for QUE with PPI. All nanoparticles showed particle size of 154-159 nm. Three lipophilic polyphenols were successfully encapsulated into PPI, with loading capacity of RES > QUE > CUR. Complexation of three polyphenols did not change the secondary structure of PPI. Results of FTIR, DSC and XRD confirmed that polyphenols changed from crystalline to amorphous state after combination with PPI. SEM pictures exhibited regular spherical microstructure of nanocomplexes. PPI shielded polyphenols from sensitive environment of ultraviolet light and thermal treatment. ABTS and DPPH radical scavenging activity of polyphenols were considerably improved through complexation with PPI. Molecular docking studies showed binding energy with 11S legumin in sequence of QUE > RES > CUR, and stronger hydrogen bonds were built between QUE and the protein than the other two polyphenols. Data in the present work may provide helpful information for encapsulation of lipophilic polyphenols with pea protein and the potential application in food science, pharmaceutical and cosmetics industries in the future.