Molecular interaction mechanism between tamarind seed polysaccharide and gluten protein: Insights into structural...

In this study, the interaction mechanism between tamarind seed polysaccharide (TSP) and gluten proteins was elucidated at both structural and molecular levels. The addition of TSP significantly enhanced the water retention capacity and rheological properties of gluten proteins, indicating improved viscoelasticity and hydration characteristics. Fourier transform infrared analysis revealed increased α-helix and β-sheet contents, along with a decrease in β-turns, which contributed to a more elastic and cohesive gluten network. Raman spectroscopy indicated that tryptophan residues were embedded in a more hydrophobic and ordered microenvironment. Changes in SDS-PAGE band patterns, coupled with the appearance of high-molecular-weight aggregates in SE-HPLC, indicated enhanced protein aggregation and disulfide-mediated network formation. Thermal analyses (DSC and TGA) revealed that the peak temperature increased from 61.20 °C to 63.53 °C, and the degradation temperature increased from 312.69 °C to 314.51 °C, demonstrating enhanced structural rigidity and thermal stability of the TSP-gluten complex. Microscopic observations revealed that low concentrations of TSP (0.5% and 1%) induced a denser and smoother gluten network. Molecular dynamics simulations further confirmed that TSP established stable multipoint hydrogen bonds and van der Waals interactions with glutenin subunits, resulting in a more compact and stable conformation. Collectively, these findings provide novel mechanistic insights into the structural reinforcement of gluten induced by TSP.