Improved bioavailability of curcumin in ovalbumin-dextran nanogels prepared by Maillard reaction

•Superb stability and redispersibility of the nanogel by Maillard modification.•Notable improvement of bioavailability of curcumin by the nanogel carrier.•Detailed mechanistic speculation by comparison with the nanoparticle.

In this work, ovalbumin-dextran nanogels were fabricated via the Maillard reaction followed by a heat-gelation process and their potential to improve curcumin bioavailability was investigated using an in vitro gastrointestinal tract. The result of electrophoresis, conjugation efficiency and yield, and far-UV circular dichroism verified the covalent attachment of dextran to ovalbumin by the Maillard reaction. The conjugates were then heated at the isoelectric point of ovalbumin to give stable nanogels. The transmission electron microscopy observation suggested that nanogels displayed a spherical structure. Curcumin was loaded into nanogels by a pH-driven method and the incorporation of curcumin affected the morphology of nanogels marginally. The transformation of curcumin in nanogels was significantly higher than that in ovalbumin nanoparticle. On the other hand, the bioaccessibility was similar for curcumin in nanogels and nanoparticle. The ovalbumin-dextran nanogels hold the potential as delivery systems for curcumin to fortify functional foods and beverages.