Characterization of quercetin-ovalbumin complexes stabilizing emulsions: A perspective on the complex binding mechanism.

Ovalbumin (OVA) is widely used in the food industry for its extremely rich nutritional value and special functional properties. Quercetin (Q) is a polyphenol with antioxidant and antibacterial properties. However, due to poor water solubility, the bioavailability of Q is greatly reduced. This study constructed a molecular model of the interaction between Q and OVA and prepared a stable emulsions. The molecular docking and molecular dynamics results showed that Q and OVA were combined through hydrogen bonding and hydrophobic interactions, and Q changed the conformation of OVA. The results of surface hydrophobicity and emulsification experiments showed that the properties of the protein were improved significantly after the interaction. Confocal laser scanning microscope showed that the emulsions type was oil-in-water system. The results of particle size and optical microscope revealed that the addition of Q-OVA complex improved the droplet size. The Low-field nuclear magnetic resonance and rheological properties showed that the addition of Q-OVA composite nanoparticles improved the stability of emulsions. The best stability of the emulsions was achieved with a 3 % addition of Q-OVA. In addition, the antibacterial experiment showed that the Q-OVA Pickering emulsions exhibited strong antibacterial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Compared with the Q-OVA complex, the diameter of the inhibition zone of the Q-OVA Pickering emulsions against E. coli and S. aureus increased by 0.11 and 0.17 cm, and the antibacterial rate increased by 2.22 % and 2.52 %, respectively. When Q-OVA Pickering emulsions was applied to fresh pork, the pH and TVC values of the pork were significantly reduced during storage (P < 0.05). This indicated that the Q-OVA Pickering emulsions had a good effect on pork preservation. These findings are important for the application of Q-OVA-based stabilised Pickering emulsions as green and safe natural preservative in the food industry.