NMR AND FTIR STUDIES OF HYDRATED PEA PROTEINS

The effects of increasing D2O hydration on the plasticization of vicil in, legumin and albumin fractions from peas were investigated using so lid state H-1-NMR transverse relaxation techniques. Measurements. show ed increases on hydration in the T-2 and intensity of the exponential component of the relaxation decay. However, a Gaussian (more rigid) co mponent remained throughout the sample composition range. This behavio ur contrasted with that observed in barley storage proteins and would indicate considerably less plasticization in legume proteins. In H-2-N MR transverse relaxation measurements of a highly D2O hydrated sample over a large temperature range, vicilin was shown to be hydrophilic in nature. However, the observed absorption of water by vicilin was less than in the HMW subunits of wheat. FTIR spectra show little structura l change in vicilin and legumin on hydration, in contrast to changes o ccurring in the cereal proteins. These differences in behaviour may be ascribed to differences between the globular structure of the legume proteins and the more linear structure of the cereal proteins.