Improving the prebiotic activity and oxidative stability of carboxymethyl curdlan - quercetin conjugates stabilized Pickering emulsions for the colonic targeting delivery of curcumin.

The carboxymethyl curdlan-quercetin conjugate (CMCD-QUE) was synthesized to stabilize curcumin (CUR) -loaded Pickering emulsions. The physicochemical properties, antioxidant activity, and prebiotic activity of CMCD-QUE were investigated. The effects of different concentrations of CMCD-QUE on CUR-loaded emulsions were also explored. CMCD-QUE exhibited excellent antioxidant activity throughout in vitro simulated gastrointestinal digestion. The particle size and electrostatic repulsion of CMCD-QUE gradually increased with rising pH, indicating that CMCD-QUE was pH-responsive. CMCD-QUE exhibited prebiotic activity and specifically promoted the enrichment of Akkermansia. The droplet size of the CMCD-QUE stabilized emulsions became smaller and more uniform as the carrier concentration increased. A concentration of 5% CMCD-QUE could be stably adsorbed at the oil-water interface of the emulsion, which exhibited a maximum encapsulated efficiency (95.85%) of CUR. CMCD-QUE showed excellent antioxidant capacity, pH responsiveness, and prebiotic activity, making it a promising multifunctional emulsifier for colon-targeted delivery of functional ingredients.