Interaction between gluten proteins and their mixtures with water-extractable arabinoxylan of wheat by rheological, molecular anisotropy and CP/MAS 13C NMR measurements

In this study, water-extractable arabinoxylan, WEAX, of wheat was isolated and mixed with gluten to observe small and large strain behavior and microscopic structure of the mixtures. The results showed that WEAX improves the viscoelasticity of gluten and makes the microscopic structure of gluten less compact. Free sulfhydryl, fluorescence anisotropy and CP/MAS 13 C NMR measurements were used to gain a better understanding of the interactions between WEAX and gluten proteins of wheat. It was demonstrated that when gluten was mixed with WEAX, the free –SH of gluten proteins cross-linked to each other or to WEAX. The cross-linking happened mainly to LMW-GS. It was shown from the fluorescence anisotropy that the conformation of glutenin was more greatly influenced by WEAX than gliadin because of the difference in their molecular conformation. In addition, it was found in this study that tyrosine groups of glutenin also played an important role in the interactions between WEAX and gluten.