High hydrostatic pressure modulation of whey protein-malvidin derivative complexes: Mechanisms, structural changes, and stability

This study investigated how high hydrostatic pressure (HHP) modulates the structural and functional properties of whey protein isolate (WPI) complexes with Malvidin-3-O-6-[acrylic acid-(2-hydroxy,4-carboxy-cyclohexanol) ester]-guaiacol (MV3ACEC). HHP at 350 MPa maximized the binding ratio (78.41 ± 0.94%) and thermal stability (denaturation temperature: 123.76 °C) of WPI-MV3ACEC, while reducing particle size (237 nm) and enhancing system stability (zeta potential: 12.7 mV). Structural analyses revealed HHP-induced conformational changes in WPI-MV3ACEC, including decreased α-helix and increased β-sheet content. Molecular simulations confirmed optimal binding affinity (-7.8 kcal/mol) at 350 MPa, dominated by van der Waals forces. HHP-treated complexes retained antioxidant activity and improved gastrointestinal stability, with MV3ACEC retention reaching 38.17% ± 0.86% post-intestinal digestion. These findings elucidate the binding mechanisms between WPI and MV3ACEC under HHP, providing novel insights for designing functional dairy products.