Self-crosslinking emulsion gels stabilized by thiolated pectin for high-efficiency curcumin encapsulation: A crosslinker-free strategy

Optimized emulsion gels were stabilized by crosslinker-free thiolated pectin. • Enhanced interfacial adsorption was verified by quartz crystal microbalance. • Curcumin encapsulation was enhanced by thiolated pectin-based emulsion gels. • Colon targeted and sustained release under in vitro simulated digestion was achieved. In this study, thiolated pectin with tunable modification degrees was successfully synthesized. Structural confirmation was achieved and the thiol group content was determined to range from 321.25 to 565.47 μmol/g. Thiolated pectin effectively stabilized gel-like emulsions with storage modulus (981.6–2027.2 Pa) remarkably higher than that of unmodified ones (46.4 Pa). Microscopic analysis revealed a honeycomb-like network that tightened with higher thiolation levels. Quartz crystal microbalance with dissipation demonstrated improved interfacial adsorption and the formation of a cohesive film via disulfide bond. The curcumin encapsulation was significantly improved to 89.87% by thiolated pectin, and curcumin retention was approximately doubled relative to unmodified pectin. Furthermore, the curcumin release was significantly inhibited in the simulated gastric and small intestinal phases, while its cumulative release during the simulated colonic phase reached up to 71.75%. This work proposed an exogenous crosslinker-free strategy for the encapsulation of lipophilic bioactives, which exhibited considerable potential for colon-targeted delivery. Download: Download high-res image (138KB) Download: Download full-size image