DETERMINATION OF WHEAT PROTEINS IN SOLUTION BY DYE BINDING IN FLOUR, DOUGH, AND BREAD CRUMB

Color development by the Bradford reagent with soluble wheat proteins has been examined so as to allow an easy and reliable application. The range examined was 0.3-3.5 mg/ml of protein. Second-order regressions fully interpret the nonlinearity in the color response. The reasons f or nonlinearity were investigated. Commercial gliadin, standard gluten , water and an acid extract of wheat flour, and bovine serum albumin w ere assayed. The absorbance developed per unit weight differed. The sp ectral response depended on the polypeptide composition of the samples assayed. Dye binding proved to be a rapid and reliable technique for the routine assay of soluble proteins in wheat flour, in dough, and af ter baking. Data obtained is in full accordance with total nitrogen de terminations.