Comparative study of three arabinogalactan-chlorogenic acid complexes: The impact of polysaccharide structure on interaction mechanism and functional performance

Polysaccharide-polyphenol non-covalent complexes have been widely utilized in food and pharmaceutical systems; however, how the intrinsic structural features of polysaccharides govern interaction mechanisms and functional outcomes remains insufficiently resolved. This study investigates how different molecular structures of arabinogalactan—gum arabic (GA), gum ghatti (GG), and peach gum (PG)—modulate the binding behavior, structural organization, and bioaccessibility of chlorogenic acid (CA). Under optimized conditions, the adsorption capacities of the three polysaccharides for CA were, in descending order: PG (82.88 μg/mg) > GG (73.84 μg/mg) > GA (63.96 μg/mg). Multispectral and conformational analyses suggested that hydrophobic interactions may be the primary force driving the GA-CA interaction, whereas electrostatic forces may be the primary force driving the GG-CA interaction. In contrast, PG-CA formation was highly dependent on conditions favoring hydrogen bonding, which also led to a significant conformational transition from a rigid to a more compact structure. Non-covalent interaction significantly enhanced the antioxidant activity of polysaccharide and the storage stability of CA. Furthermore, in vitro gastrointestinal digestion demonstrated that complexes, especially with PG and GG, effectively inhibited the rapid release of CA and improved its bioaccessibility. These results demonstrate that the molecular structural features of arabinogalactans govern their interaction mechanisms with polyphenols, thereby directly controlling the functional performance of the resulting complexes. This work provides a mechanistic framework for the rational design of polysaccharide-based delivery systems for polyphenols in functional food applications.