Dynamic regulation of mung bean globulin amyloid fibrillation by Gallic acid: Structural and functional insights

Amyloid fibrils derived from plant proteins offer a novel strategy for constructing food systems with both structural and functional properties. However, the stage-specific effects of polyphenols on protein fibrillation remain unclear. In this study, gallic acid (GA) was introduced at the initial stage (MBGF0), the end of the lag phase (MBGF15), and the end of the growth phase (MBGF240) to investigate its regulatory effect on mung bean globulin fibrillation (MBGF). Results showed that GA addition at MBGF0 prolonged the lag phase, whereas GA addition at MBGF15 accelerated the fibrosis process. Moreover, GA addition at different fibrillation stages reduced Thioflavin T fluorescence intensity, β-sheet content, and surface hydrophobicity, indicating that GA disrupted the ordered assembly of MBGF. Molecular dynamics simulations revealed that GA binding induced local conformational rearrangements of MBG, reduced conformational fluctuations, and enhanced structural stability. Functional analysis showed that GA improved the emulsifying properties of complexes at different fibrillation stages, with MBGF240-GA complex exhibiting the highest emulsifying activity index (23.50 m²/g) and emulsifying stability index (84.52 %), as well as excellent rheological properties. In summary, this study elucidates the dynamic regulatory effects of GA on mung bean globulin fibrillation and provides a theoretical basis for polyphenol-mediated modulation of protein structure and functionality.