Investigation of the interaction mechanism of citrus pectin-polyphenol-protein complex.

Citrus pectin is an anionic polysaccharide in citrus, which may improve the stability of citrus juices. This study investigated the influence of citrus pectin on the stability of protein-polyphenol complexes in the citrus juice model system and its interaction mechanism by multispectral and molecular dynamics (MD) simulations. Dynamic light scattering (DLS) and differential scanning calorimetry (DSC) showed that the citrus pectin-proanthocyanidin-zein complex improved the model citrus juices' cloud and thermal stability. Molecular dynamics (MD) simulations suggested that both pectin and proanthocyanidin bound to the U-shaped cavity of the zein molecules. Electrostatic and van der Waals forces were predominant in citrus pectin-zein. In contrast, van der Waals forces predominantly drove in proanthocyanidin-zein. This study indicated that citrus pectin could stabilize juice by delaying the onset of protein-polyphenol haze formation, which may provide new strategies for improving the quality, stability, and nutritional profile of fruit juice systems.