Effect of different low-methoxyl pectin emulsion gel delivery system: In vitro bioaccessibility and bioactivity of encapsulated curcumin.

Pectin emulsion gel has demonstrated efficacy in encapsulation and colon-targeted delivery of curcumin, but their impact on bioactivity after digestion has not been studied yet. Results showed that after simulated digestion, emulsion gel system of high hydrostatic pressure-assisted enzymatic de-esterified low-methoxyl pectin (HHP-pectin) retained higher percentage of curcumin in the colon (88.89 ± 0.87%) as compared to alkaline de-esterified low-methoxyl pectin (A-pectin), and their biopotency with loaded curcumin was more significant at lower degree of methoxylation (DM). However, the system with A-pectin showed higher bioactivity than HHP-pectin at the same DM (5-10%), exhibiting higher curcumin micellar content (52.40 ± 5.98%), antioxidant activity, and inhibition of Caco-2 colon cancer cells proliferation and secretion of NO, TNF-α, and IL-6, thereby modulating anti-inflammatory activity. Thus, these results suggested that the emulsion gel delivery system of pectin at lower DM (5-10%) especially A-pectin successfully protected physiological activity of curcumin to targeted site and improved the bioactivity of loaded curcumin and provided the theoretical foundation for nutraceutical applications.