Complexation between mannoprotein-grape polysaccharide nanoparticles and quercetin was associated with color...

Different mannoprotein (MP)-grape polysaccharide (GP) nanoparticles (MGPN) were fabricated and complexed with quercetin to analyze their abilities and mechanisms in modulating the color of model red wine solutions (MRWS). MRWS showed yellowish hue recession of up to 92.52%, which should be associated with the complexation ability of MGPN towards quercetin. MGPN of 75% GP proportions with Ca²⁺ or K⁺ contained 2.2- to 10-fold or 1.64- to 4.48-fold higher quercetin than other MGPN counterparts, which conferred MRWS the highest and second highest yellowish hue recession rates, respectively. The surface hydrophobicity, Zeta-potential, and FTIR data together indicate that Ca²⁺ and K⁺ might strengthen the hydrogen bonds/electrostatic interactions and hydrophobic interactions between MGPN and quercetin, respectively. Molecular dynamic simulation suggests that increased GP proportions in MGPN with Ca²⁺ benefited quercetin complexation by improving 26.3%-40.48% structural stabilities and increasing 13.36%-40.1% complexed quercetin molecules in the MGPN-quercetin complexes, rather than enhancing the interaction energies.