Dynamic rheological properties of native and cross-linked gliadin proteins

A comparison of cross-linked and native gliadin suspensions, with respect to the state of protein globular structure was carried out using small-angle X-ray scattering (SAXS), dynamic light scattering (DLS) and rheological analysis. Gliadin suspensions were also analyzed in the presence and absence of glycerol. DLS analysis showed that Rh increased only with gliadin/EDC/NHS suspensions. However, Kratky plots revealed that gliadin and gliadin/l-cysteine maintained their globular shape even in absence or presence of glycerol. Rheological experiments revealed that gliadin and gliadin/l-cysteine suspension exhibited a similar profile with three main domains, and a sol–gel transition. Gliadin/EDC/NHS did not present any sol–gel transition, and this fact corroborates with DLS results and the hypothesis of lower protein–protein interaction, which are in agreement with G″>G′.