Covalent engineering of pectin-whey protein isolate conjugates enhances mucoadhesion and bioaccessibility of curcumin microparticles: Strategic impacts of crosslinking modalities

This study systematically investigates the structure-function relationships between Maillard-glycated (PWM) and genipin-mediated crosslinked (PWG) pectin-whey protein isolate (WPI) complexes, with particular emphasis on their differential impacts on bioadhesive performance and digestion profiles for curcumin-loaded delivery systems. Both crosslinking strategies induced structural unfolding of WPI and endogenous pectin proteins, exposing amino-active sites that facilitated their reconstitution into stable complexes. PWG developed denser and more homogeneous hydrophobic microdomain networks compared to PWM. Curcumin was encapsulated via hydrogen bonding and hydrophobic interactions within these networks. Ex vivo intestinal adhesion assays demonstrated PWG loaded curcumin (PWG-Cur) achieved 28.69 % particulate retention in colonic environments, representing 7.0-fold and 1.75-fold enhancements over free curcumin and PWM loaded curcumin (PWM-Cur), respectively. In vitro digestion models confirmed PWG-Cur's superior bioaccessibility (22.46 %), reflecting a 37 % enhancement over PWM-Cur (16.35 %). These findings provide critical design principles for engineering mucoadhesive pectin-polyphenol delivery platforms capable of precisely modulating cargo release while enhancing bioaccessibility.