Physicochemical and functional properties of lactoferrin-hyaluronic acid complexes: Effect of non-covalent and covalent interactions

The molecular characteristics and functional properties of lactoferrin (LF)-hyalumnic acid (HA) non-covalent complexes and conjugates formed by physical mixing and chemical conjugation were compared. LF and HA interactions were characterized using phase behavior, particle size, zeta-potential and isothermal titration calorimetry (ITC) analysis. The physicochemical and functional properties of the LF-HA complexes and conjugates were also measured, including their foaming, emulsifying, and antioxidant capacities. LF and HA formed molecular complexes over a wide range of pH values, resulting in changes in particle size, charge and structure. The net charge and thermal stability of the proteins in the LF-HA complexes and conjugates were higher than that of free proteins. Covalently attaching HA to LF significantly (p < 0.05) improved its emulsifying capacity, with the highest emulsifying activity index (47.7 +/- 0.1 m(2)/g) and emulsion stability index (83.2 +/- 0.4 min) being obtained, but it did not improve its foaming properties. The antioxidant capacity of LF in complexes and conjugates was increased by around 9% and 10%, respectively. This study showed that the functional performance of LF could be enhanced by forming complexes or conjugates with HA, which may extend its use in a variety of food applications.

Automated summary

The study compared the molecular characteristics and functional properties of lactoferrin (LF)-hyaluronic acid (HA) non-covalent complexes and conjugates formed by physical mixing and chemical conjugation. It was found that covalently attaching HA to LF significantly improved its emulsifying capacity and antioxidant capacity, but did not improve its foaming properties. This suggests that forming complexes or conjugates with HA could enhance the functional performance of LF in various food applications.