Nanostructured Lipid Carrier-Filled Hydrogel Beads for the Delivery of Curcumin: Digestion, Intestinal Permeation, and Antioxidant Bioactivity After Gastrointestinal Digestion

<b>Background/Objectives:</b> The aim of the present study was to develop nanostructured lipid carrier (NLC)-filled hydrogel beads for the delivery of curcumin in functional foods. <b>Methods:</b> Curcumin-loaded NLC-filled hydrogel beads based on calcium alginate were developed using the extrusion method. Various preparation parameters, physicochemical characteristics, gastrointestinal fates, and antioxidant bioactivities were studied to confirm the feasibility of this delivery system. <b>Results:</b> Curcumin-loaded NLCs were successfully filled into hydrogel beads with an encapsulation efficiency above 80%. The stability test displayed that the stability of curcumin encapsulated within NLCs was further enhanced when the NLCs were filled into beads. During in vitro digestion, the lipolysis rate of the lipid matrix and the release rate of curcumin encapsulated in NLCs were adjusted by the hydrogel beads. The ex vivo intestinal permeation study indicated that the intestinal permeation of curcumin from the digestion products of curcumin-loaded NLC-hydrogel beads, prepared with appropriate alginate concentrations (0.5% and 1%), was significantly enhanced compared to that of curcumin-loaded NLCs. Furthermore, the digestion products of curcumin-loaded NLC-hydrogel beads (1% alginate) exhibited significantly enhanced antioxidant bioactivity compared to those of curcumin-loaded NLCs. <b>Conclusions:</b> This study demonstrated that NLC-hydrogel beads might be a promising delivery system for hydrophobic bioactive compounds in functional food systems.