Combined effect of carboxymethylcellulose and salt on structural properties of wheat gluten proteins

The interactions of carboxymethylcellulose (CMC) with gluten proteins (including glutenin and gliadin fractions) at different salt content were investigated. It has been found that CMC could bind hydrophobic sites of the gluten and glutenin. A higher percentage of beta-sheet structures were observed in the gluten and glutenin when adding salt, but CMC addition inhibited the effect of salt on gluten and glutenin to some extent and maintained the original secondary structures of proteins. The tertiary structures of three proteins were affected by the addition of CMC and salt. CMC could protect the energy-stable disulfide bonds of three proteins from destruction by salt. The combination of salt and CMC can improve the thermal stability of three proteins. Moreover, the low-molecular-weight glutenin has stronger ability to bind with CMC than gliadin, and non-covalent bonds (hydrogen bond, electrostatic and hydrophobic interaction) played an important role in the mixing process besides disulfide bonds.