The interaction mechanism between zein and folic acid in alkaline aqueous solutions: An experimental and molecular simulation study

Folic acid (FA) is a vitamin that is not very soluble in water and is sensitive to the environment. Therefore, it is important to find suitable carriers for it. This research looked into how zein interacts with folic acid in alkaline aqueous solutions using experiments, molecular docking, and molecular dynamics simulation. Fluorescence spectroscopy showed that zein's quenching by folic acid was mainly static, and the main driving force behind this interaction was van der Waals forces and hydrogen bonds. The formation of zein-folic acid complexes was confirmed by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, and circular dichroism spectroscopy. The results also showed that the structure of zein changed when it interacted with folic acid. Dynamic light scattering analysis revealed that the addition of folic acid caused proteins to aggregate. The aggregates of complexes had an irregular shape and were large, as observed under scanning electron microscopy and transmission electron microscopy. Molecular simulation was used to further investigate the interaction mechanisms. According to the findings, the folic acid molecule interacted with zein in a shallow recess near the protein surface. The dominant forces at play in the zein-folic acid interaction were van der Waals forces and electrostatic forces, including hydrogen bonding. This study exemplifies the interaction folic acid with zein in alkaline aqueous solutions and sheds light on how zein can be used as a carrier for folic acid.