Cereal Chem 44:620 - 630.  |  VIEW ARTICLE
Studies with Radioactive Tracers. XI. The Use of N-Ethylmaleimide-1-14C in the Determination of Flour Sulfhydryls and Correlations Between Masked Sulfhydryls and Loaf Volumes.

C. C. Lee and T.-S. Lai. Copyright 1967 by the American Association of Cereal Chemists, Inc. 

Further studies are reported on the radiochemical method for determining sulfhydryls of flour proteins, based on the reaction of the -SH group with N-ethylmaleimide-1-14C, followed by hydrolysis to give 14C- labeled S-succinyl-L-cysteine (III-14C). This hydrolysis product, III-14C, is separated by paper chromatography and its activity is converted to -SH concentration with the aid of a calibration with known concentrations of glutathione. By this method, the flour sulfhydryls can be separated into water-soluble and water-insoluble fractions and into accessible and masked types. Such -SH determinations were carried out on 21 flours and the results were analyzed statistically with loaf volume data obtained from baking with various levels of bromate. Highly significant positive correlations were obtained between masked sulfhydryls and loaf volumes. The highest correlation coefficients were found between masked sulfhydryls and maximum loaf volumes (+0.78**) and between protein contents and masked sulfhydryls (+0.77**).