The interaction between water-insoluble pentosan and gluten of the whole wheat

The water-insoluble pentosan (WIP) and gluten were extracted, and the interactions of WIP and gluten at different water level and ionic strength were measured by small amplitude oscillation tests and atomic force microscopy (AFM), and visualized by scanning electron micrographs (SEM). The results showed that the viscoelasticity of gluten and gluten-WIP mixtures greatly increased with the increase of water level, and decreased when water level was higher than 50%. The WIP significantly (p < 0.0001) improves viscoelasticity of gluten. The G′ and G″ of gluten and gluten-WIP mixtures were significantly (p < 0.0001) increased with the increase of NaCl concentration, and reached maximum when NaCl concentration was 4.0%. The SEM observations showed that the network of gluten-WIP mixtures was homogeneous and rather dense with a regular structure compared with that of gluten. From AFM detection, it was found that the single-molecule bond rupture force between the WIP and gluten proteins was strengthened with the increase of NaCl concentration, which can partly explain the rheological property and microstructure changes of WIP-gluten mixtures.