Nature of pectin–protein–catechin interactions in model systems: Pectin–protein–catechin interactions

Apple pectins, proteins and catechins were combined in model systems, and the resulting hazes were measured by spectrophotometric method, a zeta potential and particle size analyzer and Ostwald viscosimeter. The amount of hazes formed depends on the concentrations of both protein and pectin. The cooperative hydrogen bonding between the numerous hydroxyl groups of pectins and hydrone and the gel-like structure developed by pectin induced the solvation or solubilization of polymers, and the protein molecule has a fixed number of polyphenol binding sites. The influence of pectin relative molecular mass and degree of esterification on the formation of suspended particles is prominent, and this makes the number of hydroxyl groups and charge of pectin which is concerned with combining protein and catechin to change a lot. More haze was observed when model systems were heated, suggesting that hydrophobic groups of protein are beneficial to their binding with phenols and pectins. The pH value affects the charged state of the protein and pectin, which influences the combination of pectin-gliadin-catechin.