Methodology was developed for the determination of free sulfhydryls in
wheat flours and doughs using NBD-Cl (7-chloro-4-nitrobenzo-2-oxa-1,3
-diazole). The solubilization of protein by sonication in sodium dodec
yl sulfate (SDS) was compared to proteolysis with Proteinase K in SDS.
Oxidation during proteolysis and disulfide cleavage during sonication
are the likely reasons for observed differences between the two solub
ilization methods. The sulfhydryl determination and both extraction pr
ocedures work effectively on model doughs and full bread formula.