A multifunctional WPC-linoleic acid-EGCG complex: structural characterization, bioactivity, and application as a butter substitute in processed cheese.

Developing multifunctional ingredients for fat reduction without quality loss is challenging. This study developed a whey protein concentrate-linoleic acid-epigallocatechin gallate (WPC-LA-EGCG) ternary complex as a butter substitute in processed cheese. Multi-spectroscopy experiments and molecular docking simulations suggested that hydrogen bonding, hydrophobic, and electrostatic interactions reconfigured protein secondary structure. At optimal EGCG levels (<0.1%), the complex showed enhanced molecular flexibility, interfacial adsorption, emulsifying activity, and stability. In vitro, the complex showed synergistic antioxidant activity, reduced IgE-binding (52.5-68.7% by enzyme-linked immunosorbent assay, ELISA), and modulated glucose consumption and lipid metabolism in 3 T3-L1 adipocytes. However, these findings are preliminary and require in vivo validation. Replacing 30.4% butter, the complex transformed the matrix into a continuous protein-dominant gel, improving texture, viscoelastic moduli (G', G″), and thermal stability. Electronic tongue evaluation detected no notable taste profile deterioration. The tailored complex offers a viable strategy for healthier low-fat dairy products with enhanced functionality and bioactivity.