13C and 1H solid state NMR investigation of hydration effects on gluten dynamics

The effect of hydration on the molecular dynamics of soft wheat gluten was investigated by solid state NMR. For this purpose, we recorded static and MAS 1H spectra and SPE, CP, and other selective 13C spectra under MAS and dipolar decoupling conditions on samples of dry and H(2)O and D(2)O hydrated gluten. Measurements of carbon-proton CP times and several relaxation times (proton T(1), T(1rho) and T(2), and carbon T(1)) were also performed. The combination of these techniques allowed both site-specific and domain-averaged motional information to be obtained in different characteristic frequency ranges. Domains with different structural and dynamic behaviour were identified and the changes induced by hydration on the dynamics of different domains could be monitored. The proton spin diffusion process was exploited to get information on the degree of mixing among different gluten domains. The results are consistent with the "loop and train" model proposed for hydrated gluten.