Impact of wheat postharvest maturation on gluten conformational and molecular properties

This study systematically explored the impacts of wheat postharvest maturation on gluten conformational and molecular properties. Results showed that postharvest maturation improved the viscosity and elasticity of dough. The analysis of gluten particle size, molecular chain morphology, and SE-HPLC demonstrated that postharvest maturation promoted gluten polymerization. Postharvest maturation induced a more hydrophobic microenvironment for tryptophan residues in gluten, and promoted the adoption of the gauche-gauche-gauche conformation in disulfide bridges. Furthermore, postharvest maturation increased the contents of ω5- (by 0.12 %), ω1,2- (by 1.76 %), and α-gliadin (by 4.41 %), with slight increases of 0.04 % and 0.96 % for D-type and B/C-type LMW-GS (low-molecular-weight glutenin subunits), respectively. Simultaneously, the intermolecular forces of gluten have been strengthened, including disulfide bonds, ionic bonds, and hydrophobic interactions. Thus, the increased gluten composition contributed to glutenin-gliadin and glutenin-glutenin polymerization via disulfide bonds, ionic bonds, and hydrophobic interactions, altered the gluten conformation, and thereby enhanced dough viscoelasticity.