Studies on the formation mechanism and multiscale structure of wheat bran dietary fiber-gluten protein complex

Abstract

The effects of wheat bran dietary fiber (WBDF) particle sizes and additional amounts on the formation mechanism and multiscale structures of the WBDF-gluten protein complex were investigated. Fluorescence spectra confirmed that the complex was controlled by static quenching. Thermodynamic analysis, noncovalent interactions, and surface hydrophobicity studies indicated that hydrophobic interaction and hydrogen bond were the primary interaction forces driving the formation of WBDF-gluten protein complex. Multispectral techniques and visual analysis showed that the complex facilitated the embedding of unfolded gluten protein when added at 3%, 6%, and 9%, which reduced the disruption of gluten network structure by WBDF. However, at higher additions (12% and 15%), more WBDF interacted with gluten protein, causing the gluten network structure to collapse. Furthermore, the microstructure showed that the complex formed by WBDF (particle size <54 μm) and gluten protein could maintain the integrity of gluten network even at 15%, thus reducing the damage to the gluten network structure. This work provides a promising theoretical basis for the mechanism of WBDF-gluten protein complex formation driven by noncovalent interaction, and contributes to the development of new functional flour products.