Cereal Chem 52:170r - 183r.  |  VIEW ARTICLE
Thiol and Disulfide Groups in Dough Rheology.

A. H. Bloksma. Copyright 1975 by the American Association of Cereal Chemists, Inc. 

The sensitivity of the rheological properties of dough to oxidation suggests that disulfide bonds play a role in dough rheology. The conversion of thiol groups into additional disulfide cross-links between chain molecules of the protein network has been considered an explanation for the stiffening of dough induced by oxidizing flour improvers. However, thiol blocking reagents, which do not form disulfide bonds, have an effect similar to that of oxidation. The stiffening of dough is apparently not primarily due to the formation of additional disulfide bonds, but rather to the removal of thiol groups. This can be explained by the occurrence of thiol-disulfide interchange reactions in dough. This hypothesis predicts that the elastic deformation of dough is restricted by disulfide cross-links, whereas the viscous deformation increases with increasing thiol content. Experiments with doughs that differed only in their thiol and disulfide contents demonstrated that there is not an unequivocal relation either between the disulfide content and the elastic deformation, or between the thiol content and the viscous deformation. There is evidence that only small fractions of the analytically determined thiol and disulfide groups are rheologically effective. The rheologically effective thiol groups are probably located in small peptides.