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H. A. Sokol, D. K. Mecham, and J. W. Pence. Copyright 1960 by the American Association of Cereal Chemists, Inc. Twelve flours of varied types were made into doughs in a farinograph and their sulfhydryl contents determined after 2, 5, 10, and 20 minutes of mixing. Sulfhydryl losses varied after 20 minutes of mixing from 38 to 64% of the original sulfhydryl content. An initial short period (2 to 5 minutes) of rapid decrease in sulfhydryl content was observed with most of the flours. With continued mixing, relatively large differences were found in the rate of decrease; treated by first-order kinetics, values for the rate constant for the 5-to-20-minute period ranged from 6 to 36 minutes - 1. Doughs from three flours (including two durums) were mixed with added flour albumin. The initial decrease in sulfhydryl content then was more rapid, while the rate of loss from 5 to 20 minutes was decreased. Stability values taken from farinograms correlated well with the sulfhydryl-loss rate constant for three hard red spring, three white, and two hard red winter wheat flours, and for the two durum flours supplemented with albumin. The nonsupplemented durums and two hard red winter wheat flours giving atypical farinograms did not show this relationship. With two flours, the rate of loss of sulfhydryl groups in 10:1 water-flour suspensions decreased much more slowly than in the corresponding doughs. |
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