Noncovalent interaction of chlorogenic acid and/or gallocatechin gallate with β-lactoglobulin: Effect on stability and bioaccessibility of complexes and nanoparticles

Abstract

Polyphenols are widely found in tea and coffee. The addition of milk can not only improve the taste and nutrition of tea and coffee, but can also improve the stability and bioavailability of polyphenols. The interaction mechanism of chlorogenic acid (CGA) and/or gallocatechin gallate (GCG) with β-lactoglobulin (β-LG) was proven here via multi-spectroscopic techniques and molecular dynamic simulation. The influence of CGA/GCG binding on the secondary structure, particle size, and thermal stability of β-LG was studied using Fourier transform infrared spectroscopy, dynamic light scattering, and differential scanning calorimetry. Furthermore, the effects of complex and nanoparticle formation on the functional improvement of CGA, GCG, and β-LG were investigated including stability and in vitro gastrointestinal digestion. The combination of CGA and GCG in the nanoparticles led to better stability and bioaccessibility than in the corresponding complexes. The functional improvement in the β-LG + CGA + GCG ternary nanoparticles was found to be the most pronounced. These results offer a theoretical foundation for improving functional dairy products and nutraceuticals containing multiple polyphenols.