Study of the interaction mechanism between theaflavin and Zein

To enhance the bioavailability and aqueous solubility of theaflavin (TF), Zein stabilized theaflavin nanoparticles were investigated. Nanoparticles were synthesized by the antisolvent precipitation method and structure, interaction mechanisms were exploited by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR), molecular docking, and gastrointestinal simulation. Under the optimized parameters, the encapsulation efficiency (EE), loading capacity (LC), average particle size, and zeta potential of nanodispersions were 84.89%, 74.11%, 441.86 ± 2.78 and −42.88 ± 0.25 mV, respectively. The nanoparticles showed good water dispersion with processes of freeze-drying and rehydration. The SEM result showed that theaflavin was successfully coated with Zein and formed a dense network structure on the surface of the particles. FT-IR and molecular docking experiments indicated that electrostatic, hydrophobic, and hydrogen bonding interactions existed in the Zein-TF nanocomplex. Compared to theaflavin, the Zein-theaflavin nanoparticles had greater stability and were released more slowly. After storage of the nanoparticles at 4 °C and 25 °C for 30 d, the encapsulation efficiency remained above 70%. This study showed that Zein-theaflavin nanoparticles were ideal emulsion stabilizers in targeted food delivery.