Mechanism behind the rheological property improvement of fava bean protein by the presence of dextran

The positive role of dextran (DX) produced by lactic acid bacteria in improving the rheological properties of fava bean protein has been confirmed, while the detailed mechanism behind this improvement has not been revealed yet. Based on this, the aim of this study was to reveal this mechanism by investigating the interactions between fava bean protein and DXs with different molecular weight (Mw). Firstly, the effects of DXs at different Mw on rheological properties of fava bean protein isolate (FPI) were evaluated. Then, the interacting force between FPI and DX were determined. Finally, the change of physicochemical properties of FPI (e.g., water-binding capacity, microstructure, particle size, secondary structure, surface hydrophobicity etc.) caused by the presence of DX were studied. DX at a higher Mw showed a more obvious impact on improving the rheological properties and water-binding capacity of FPI. Hydrophobic force was the main interacting force between FPI and DX. A network structure formed, and the particle size and surface hydrophobicity of FPI increased due to the presence of DX. The possible mechanism behind the rheological property improvement of FPI by the presence of DX was the enhanced water-binding ability of a newly formed network structure. The mechanism revealed in this study may provide some theoretical guidance for the application of DX in protein-based food.

Automated summary

The positive role of dextran (DX) produced by lactic acid bacteria in improving the rheological properties of fava bean protein has been confirmed. The higher molecular weight DX has a more obvious impact on improving the rheological properties and water-binding capacity of fava bean protein isolate (FPI). Hydrophobic force is the main interacting force between FPI and DX. The presence of DX forms a network structure and increases the particle size and surface hydrophobicity of FPI.