Unraveling the relationship between large-magnitude extensibility of Lamian dough with gluten molecular interactions and subunit composition

Abstract

The relationship between large-magnitude dough extensibility with gluten molecular interactions and subunit compositions were studied. Dough extensibility, a critical property for Lamian making, was achieved by adding sodium metabisulfite (SMBS) and improved by decreasing the pH level (6.3), which was indicated by the decrease in tensile force and increase in tensile distance. However, the loss of dough extensibility was induced by the prolonged resting time, which was more pronounced for doughs at low SMBS addition (0.005 %) and high pH value (10.8 and 13.0). Changes in the intermolecular forces and gluten subunits were associated with the loss of dough extensibility, accompanied with a fragmented gluten network. As the resting time increased, doughs at low SMBS addition and high pH showed decreases in free sulfhydryl groups and sodium dodecyl sulphate-extractable protein (SDS-EP) and increases in disulfide bonds. Increasing ionic bonds at high alkaline pH also contributed to high tensile stress and low tensile strain. The extractability of gliadin and D-low-molecular-weight glutenin subunits decreased at high pH value. Optimal level of disulfide and hydrogen bonds along with an appropriate gluten subunit distribution would play a constructive role in improving the large-magnitude dough extensibility.