High‐power ¹³C and ¹H nuclear magnetic resonance in dry gluten

High‐resolution, solid‐state ¹³C NMR spectra of wheat gluten obtained under a variety of acquisition conditions are reported. These spectra are compared with the results from a ¹H relaxation study of dry gluten in which the transverse relaxation times, the spin–lattice relaxation times in the rotating frame and the spin–lattice relaxation times in the laboratory frame at three different Larmor frequencies are characterized. It is concluded that ¹³C experiments, the proton transverse relaxation measurements and the rotating frame results distinguish between protein and lipid motional environments, whilst the laboratory frame proton spin–lattice relaxation results detect two separate protein environments. The relationship between the laboratory frame spin–lattice relaxation time constants and Larmor frequency is consistent with a model of macromolecular motion in which the polymer chains are held between cross‐link points. Observed changes in the various proton relaxation times on removal of lipid or disruption of disulphide cross‐links are interpreted in terms of the frequency and anisotropy of molecular motions in the gluten system.