Temperature dependence of relaxation spectra for highly hydrated gluten networks

In the present investigation, the temperature dependence (0–50 °C) of the relaxation spectrum of hydrated gluten was studied using novel numerical algorithms. Tikhonov regularization, in conjunction with the L-curve criterion for optimal calculation of the regularization parameter, was used to generate the relaxation spectrum from stress relaxation measurements on shear. The methodology used revealed six molecular events with baseline resolution that could be grouped into fast- and slow-relaxation regimes. The fast-relaxation regime exhibited strong temperature dependence whereas the slow one is temperature independent indicating on the whole two dominant mechanisms of interactions. The “loop and train” structural model for gluten interactions was found adequate to describe the relaxation events in this system, with the fast regime being assigned to interactions due to hydrogen bonding whereas the slow one to permanent cross-linking of the entire network. Findings of the present investigation provide fundamental understanding and give new insights into the complexity of interactions and relaxation modes of hydrated gluten.