Controlled stepwise reduction of disulfide bonds and heat-induced modification of wheat dough proteins

A reducing solution of 2-mercaptoethanol and its oxidized form 2-hydroxyeth yl disulfide, whose variable concentrations set variable disulfide reductio n potentials, was applied to progressively reduce the disulfide bonds of pr oteins extracted from doughs made from Meneba and Robin Hood flour. Several dough proteins had disulfide bonds stronger than those of other dough prot eins. A SDS-sedimentation method was applied to monitor the baking of dough into bread. Dough proteins susceptible to heat (baking) were studied by SD S-fractionation, extraction with reducing alcoholic solution, SDS-PAGE, and N-terminal protein sequencing. High or low molecular weight glutenins, alp ha, beta, and gamma-gliadins, alpha-amylase inhibitor, and alpha-amylase tr ypsin inhibitor were identified among the dough proteins modified by heat ( as shown by reduced solubility in aqueous-SDS solution). The heat-induced m odification of the gliadins and glutenins might contribute to the coagulati on of dough proteins, while the heat-induced modification of the amylase or trypsin inhibitors might contribute to the regulation of endogenous or exo genous amylolytic or proteolytic activities in dough or bread.