Effect of non-covalently bound alkaline amino acids on the structural characterization, microstructure, and rheological properties of whey protein emulsion gel

The objective of this study was to explore the impact of L -arginine (Arg) and L -lysine (Lys) on the structural changes and rheological properties of whey protein isolate (WPI) emulsion gels through the utilization of multi-spectroscopic techniques and rheological analysis. The results indicated that the incorporation of Lys/Arg caused WPI molecules to become unfolded, thus exposing hydrophobic amino acids and altering the microenvironment of aromatic amino acids. Microstructural studies revealed that WPI emulsion gels containing 0.5% Lys or 2% Arg resulted in a more uniform and compact network structure. This phenomenon could be attributed to the capability of Lys/Arg to improve the hydrophobic interactions and hydrogen bonding between molecules during gel formation, ultimately leading to a network structure characterized by excellent rheological properties, textural properties, and water-holding capacity. These findings provide a theoretical for the development of emulsion gels with improved structural and rheological properties. • Lys/Arg induced the exposure of aromatic and hydrophobic amino acid. • Emulsion gels were fabricated with different Lys/Arg concentrations. • Lys/Arg improved the rheological and structural properties of WPI emulsion gel. • Lys/Arg promoted the formation of tight gel network structure.