The behavior of whey protein isolate-curcumin complex at the oil-water interface

It was very common to use nanoparticles and nanoemulsions with the combination of proteins and hydrophobic bioactives to effectively prevent and treat chronic diseases. This work was to evaluate the stability of whey protein isolate (WPI) and curcumin (CUR) complex made with the anti-solvent precipitation technique and the pH shifting methods in oil-water bulk and interface. The interaction between WPI and CUR were investigated using fluorescence spectroscopy, Fourier transform infrared spectroscopy and molecular docking. The changes of the WPI-CUR in the oil-water bulk and interface were characterized by the circular dichroism spectroscopy, UV spectroscopic, confocal laser scanning microscopy and molecular dynamics simulation. Results indicated that the interactions between WPI and CUR were hydrogen bonding and hydrophobic interaction. The WPI-CUR complex was unstable at the oil-water interface, CUR detached from the complex and migrated to the oil phase. These findings would be of importance in illustrating the behavior of whey protein isolate-curcumin complex at the oil-water interface.