What do we really understand about wheat gluten structure and functionality?

The structure and functional properties of wheat gluten have fascinated cereal chemists for over a century and a range of approaches have been taken to understand the structures and interactions of the gluten protein complex and how these are established. Nevertheless, our knowledge is still far from complete. We therefore review the current state of our knowledge and identify gaps and priorities for future research. The evidence for the forces that determine the interactions of the individual proteins in the gluten complex is re-evaluated, which allows us to define the relative contributions of covalent disulphide bonds and non-covalent forces (hydrogen bonds, hydrophobic and electrostatic interactions) and to relate these interactions to the amino acid sequences, structures and properties of the individual protein subunits. We also discuss the evidence for the pathway of gluten protein synthesis, deposition and assembly in the developing grain and how the assembly may be modified during the maturation of the grain.