Effect of cationized guar gum on stability and bioaccessibility of curcumin-loaded Pickering emulsion stabilized by starch nanoparticles

Abstract

To enhance stability and bioaccessibility of curcumin in Pickering emulsions stabilized by starch nanoparticles (SNP), cationized guar gum (CGG) was incorporated into the emulsion. Zeta potential results revealed that SNP and CGG formed electrostatic interactions, resulting in stable interfacial layer with higher hydrophobicity. Adding 0.4 % CGG maintained a homogeneous phase without significant droplet size change for up to one month. The emulsion with 0.4 % CGG demonstrated stable storage under varying pH (4-10), ionic strength (0-10 mM NaCl), and freeze-thaw cycles (up to 3). When optimized Pickering emulsion system was applied to curcumin encapsulation, curcumin-loaded emulsions were stably maintained for up to one month. The curcumin retained approximately 100 % stability under thermal (90 °C) and UV (12h) treatments. In the optimized emulsion, starch components resisted digestion in oral and gastroenteric phases but were primarily digested in small intestine, resulting in an increasing bioaccessibility from 88.23 to 96.92 %.

Keywords: Bioaccessibility; Cationic guar gum; Curcumin; Pickering emulsion; Starch nanoparticles.