Preparation and characterization of zein/carboxymethyl dextrin nanoparticles to encapsulate curcumin: Physicochemical stability, antioxidant activity and controlled release properties

•Zein/ carboxymethyl dextrin nanoparticles were fabricated to deliver curcumin.•Addition of carboxymethyl dextrin enhanced encapsulation efficiency of curcumin.•Complex nanoparticles improved stability and antioxidant activity of curcumin.•Complex nanoparticles delayed release of curcumin in gastrointestinal fluids. In this work, zein/carboxymethyl dextrin nanoparticles were successfully fabricated at different zein to carboxymethyl dextrin (CMD) mass ratios. Zein/CMD nanoparticles with the negative charge and the smallest size (212 nm) were formed when the mass ratio of zein to CMD was 2:1, exhibiting improved encapsulation efficiency of curcumin (85.5%). Electrostatic interactions, hydrogen bonding and hydrophobic interactions were main driven forces for nanoparticles formulation and curcumin encapsulation. Fourier transform infrared spectroscopy determined curcumin might be partially embedded in CMD during encapsulation. The spherical structures of zein/CMD nanoparticles and curcumin-loaded zein/CMD nanoparticles were observed by transmission electron microscopy. The photothermal stability and antioxidant activity of curcumin were significantly enhanced after be loaded in zein/CMD nanoparticles. Furthermore, encapsulation of curcumin in zein/CMD nanoparticles significantly delayed the release of curcumin in simulated gastrointestinal fluids. These results indicated that zein/CMD nanoparticles could be effective encapsulating materials for bioactive compounds in food industry.