Correlation of Gluten Molecular Conformation with Dough Viscoelastic Properties during Storage

Abstract:: Significant correlations exist for the total sample between the dough viscoelastic properties and quality, but little information about these links is available. This study investigates the relationship between the gluten molecular conformation and the dough viscoelastic properties of the Zhengmai 379 wheat variety with different relative humidity (RH) values during storage. The results showed that protein extractability, free sulfhydryl (SH) groups, and wet gluten contents decreased to a certain degree during storage, while the glutenin quantity significantly varied. Significant negative correlation coefficients were found between the dough viscosity at 50% RH and the β-turn contents at 40% RH (−0.918) or 60% RH (−0.949) (P < 0.01), the dough viscosity at 50% RH and the β-turn contents at 50% RH (−0.912) (P < 0.05), and the dough viscosity at 50% RH and the α-helix/β-sheet ratio at 40% RH (−0.875), 50% RH (−0.869), or 60% RH (−0.843) (P < 0.05). Significant correlation coefficients were further observed between the dough viscosity at 50% RH and the β-sheet contents at 60% RH (0.927) (P < 0.01) and between the dough viscosity at 50% RH and the β-sheet contents at 40% RH (0.910) or 50% RH (0.908) (P < 0.05). A decrease in the free SH groups of gluten and an increase in the low-molecular weight contents suggested that gliadin was incorporated via SS crosslinking to the glutenin-like protein, which did not dissolve in ethanol.Supported by National Key Research and Development Program (2016YFD0400200), National Natural Science Foundation of China (31571780 and 31371850), General Science and Technology Research Projects of Zhengzhou (N2013G0077), Key Scientific Research Project of Universities in Henan Province (16A210018), and the focus on Fostering Basic Research Fund of Henan University of Technology (2013JCYJ05) Keywords:: Wheat gluten, Viscoelastic properties, Free sulfhydryl groups, Gluten secondary structure