Cereal Chem. 70:553-557   |  VIEW ARTICLE

Changes in the Levels of Glutathione and Cysteine During the Mixing of Doughs with L-threo- and D-erythro-Ascorbic Acid.

R. Sarwin, G. Laskawy, and W. Grosch. Copyright 1993 by the American Association of Cereal Chemists, Inc. 

An isotope dilution assay was developed for free reduced glutathione (GSH), total glutathione GSH, oxidized glutathione, and protein-glutathione mixed disulfides), free cysteine (Cys), and total Cys (Cys, cysteine, and protein-Cys mixed disulfides). The isotope dilution assay was checked by the determination of these compounds in some flours and in crude glutenins. It was applied to flours of two wheat cultivars (DNS and Kanzler) and to their doughs, which had been mixed for 3 min at 30 C. In the DNS doughs without additions, GSH (values in nmol/g) decreased from 100 to 44 and Cys increased from 13 to 42 in the K doughs, GSH decreased from 35 to 17 and Cys increased from 8 to 18. Addition of L-threo-ascorbic acid accelerated the disappearance of GSH and partially inhibited the increase of Cys. In contrast, D-erythro- ascorbic acid was inactive. The results confirmed the hypothesis that the improver action of L-threo- ascorbic acid is caused by a rapid oxidation of GSH to its rheologically inactive disulfide.