Fabrication of colloidal stable gliadin-casein nanoparticles for the encapsulation of natamycin: Molecular interactions and antifungal application on cherry tomato

Natamycin was encapsulated in gliadin-casein nanoparticles (G-C NPs) to control black rot in cherry tomato against Alternaria alternata. The G-C NPs with a mean particle diameter of 211 ± 4 nm were prepared using an anti-solvent method. The composite NPs showed better stability against neutral pH, ion, and storage than gliadin NPs. The quenching of gliadin by natamycin was static with a constant of 5.99 × 10-12 M-1∙S-1, and was spontaneous with a free energy of -23.5 kJ∙M-1 at 298 K. Both hydrophobic stacking and hydrogen bonds between natamycin and gliadin were found as the major driven force in the formation of the complex. The NPs kept the antifungal activity of natamycin with improved photostability. The NPs coatings exhibited better results than natamycin in controlling black rot on cherry tomato. This study shows the potential of the G-C NPs as all-natural delivery systems for natamycin in post-harvest treatments.