Formation and functional improvement of α-casein, β-lactoglobulin, and hyaluronic acid conjugates via the Maillard reaction: Comparison with different mass ratios

Milk protein and hyaluronic acid (HA) at different mass ratios were systemically characterized using the Maillard reaction. Combining FTIR and molecular docking results, both conjugates, α-casein-HA (α-CN-HA) and β-lactoglobulin-HA (β-Lg-HA), were prepared via hydrogen-bond interactions. Binding of HA promotes the structural folding of milk proteins and alters their secondary structures. The α-CN-HA and β-Lg-HA conjugates exhibited significantly improved solubility thermal and antioxidant activity. The functional properties of the conjugates were modulated by varying the ratio of milk proteins to HA. The α-CN:HA 1:2 ratio had the highest denaturation temperature (110.1 °C). For β-Lg-HA, the highest denaturation temperature (112.1 °C) was observed at a 1:4 ratio. Antioxidant capacity increased with decreasing HA content; the highest value was observed at a mass ratio of 3:1 for both conjugates. Our findings suggest that Maillard reaction improves the physiological and functional properties of milk proteins and HA conjugates.