High‐resolution proton, carbon‐13 and nitrogen‐15 nuclear magnetic resonance studies of wheat proteins at high magnetic fields: Spectral assignments, changes with concentration and heating treatments of flinor gliadins in solution—comparison with gluten spectra

The first high‐field and high‐resolution proton, carbon‐13 and nitrogen‐15 nuclear magnetic resonance (n.m.r.) spectra of gliadin solutions are reported. Collective assignments are proposed based on ‘random coil’ chemical shifts and amino acid analysis of gliadins. Additional information from X‐ray diffraction, photoacoustic spectroscopy, dielectric relaxation and electrophoretic measurements is considered in the interpretation of the n.m.r. spectra. Marked changes in the n.m.r. spectra of gliadin solution were observed with increasing concentration or temperature. An interpretation of these effects in molecular terms is proposed and the practical implications of n.m.r. measurements for wheat variety identification and correlation with rheological testing indicated. The relevance of the results to studies of glutens is also noted.