Preparation and characterization of tilapia protein isolate – Hyaluronic acid complexes using a pH-driven method for improving the stability of tilapia protein isolate emulsion.

• Tilapia protein isolate (TPI)-hyaluronic acid (HA) complexes were prepared using a pH-driven method. • The state of complexes was modulated by TPI: HA ratio. • Hydrogen bonding and hydrophobic interactions were confirmed during complex formation. • The complexes have improved emulsifying properties compared to TPI. • HA significantly improved the stability of TPI emulsion. This study aimed to investigate the non-covalent complexation between hyaluronic acid (HA) and tilapia protein isolate (TPI) on the stability of oil-in-water (O/W) TPI emulsion. The results showed that HA binds to TPI through electrostatic, hydrophobic, and hydrogen bonding interactions, forming homogeneous hydrophilic TPI-HA complexes. The binding of HA promoted the structural folding of TPI and altered its secondary structure during pH neutralization. The TPI-HA complexes presented significantly improved EAI and ESI (P < 0.05) when the HA concentration was 0.8 % (w/v). Emulsion characterization showed that HA promoted the transfer of TPI to the O/W interface, forming an emulsion with excellent stability, which, combined with the high surface charge and strong spatial site resistance effect of HA, improved TPI emulsion stability. Therefore, non-covalent complexation with HA is an effective strategy to improve the stability of TPI emulsion. [ABSTRACT FROM AUTHOR]