Cereal Chem 43:187 - 194.  |  VIEW ARTICLE

Colloid Titration of Wheat Proteins, Dough, and Flour.

D. Yoshino and H. Matsumoto. Copyright 1966 by the American Association of Cereal Chemists, Inc. 

Colloid titration, based on a stoichiometric combination between positive and negative ionic high- molecular-weight compounds, was applied to wheat flour, dough, and wheat proteins. Polyvinyl alcohol sulfate was used in the titer solution, and chitosan hydrochloride or methylated chitosan iodide was used as the standard positively charged polymer. Colloid titration curves, in which an equivalent charge per g. of protein was plotted against pH of medium, indicated that the positive net charge was increased in the following order at pH values lower than 4, crude gluten less than defatted gluten less than wheat flour less than soluble protein. A marked increase of charge in gluten was observed when lipid was removed. The positive charge of dough dispersed in 3M urea at pH values lower than 4 decreased as mixing time increased. These findings suggest a possible interaction between polymer ions during mixing and dough development.