Isolation treatments and effects of gliadin and glutenin fractions on dough mixing properties

The effects of a range of solvents and buffers commonly used in the isolation of gliadin and glutenin polypeptides were evaluated on the functionality of gliadins and glutenins in a small-scale dough mixer. Fractions from two wheat cultivars that differed in mixing behavior and high molecular weight glutenin subunit composition were studied. Dialysis or addition of dilute acetic acid rather than water before drying was critical for mixing behavior to remain unaltered. The mixing behavior of gliadin and glutenin fractions treated with a range of buffers and solutions, including sodium dodecyl sulfate, urea, aqueous alcohols and acetonitrile, and low pH buffers was unaltered after dialysis against acetic acid. In contrast, exposure of both gliadins and glutenins to reducing agents altered the mixing behavior of these fractions. The results will guide research on the isolation of single polypeptides for functionality studies and development of a simple dough for structure and function studies.