Cereal Chem 69:315-320   |  VIEW ARTICLE

Effects of Metal-Complexing Agents on Water Binding by Gluten.

R. L. Clements. Copyright 1992 by the American Association of Cereal Chemists, Inc. 

Glutens from four soft red winter wheat cultivars were obtained by sedimentation (fractionation) of flours in water, in ethylenediaminetetraacetic acid (EDTA) at four concentrations (0.00125-0.0075M), and in 1M sodium chloride. Glutens then were repeatedly extracted with water by suspension of fragmented gluten in water followed by centrifugation at 1,000 x g. Volumes of sediments were measured after each centrifugation to determine water binding. Glutens obtained by sedimentation of flours in 0.0075M EDTA or in 1M sodium chloride became increasingly hydrophilic during water extraction, forming voluminous gels. Glutens from flours fractionated in 0.00125M EDTA did not swell. When flours were fractionated in 0.0025M EDTA, swelling of Becker gluten approached the response from fractionation of flour in 0.0075M EDTA, but Hillsdale gluten exhibited only slight swelling. Glutens from Caldwell and Compton flours showed intermediate swelling. Glutens obtained by fractionation of flours in water followed by treatment with sodium chloride or EDTA and lyophilized also exhibited measurable swelling when gluten powders were extraacted with water. Wide differences between swelling responses of Becker and Hillsdale glutens, regardless of location or crop year, indicate a genetic basis for the differences. Results suggest that divalent cations bound to gluten are removed by EDTA (or by sodium chloride at high concentrations), resulting in increased interaction with water. Amounts of EDTA required to induce maximum response appear to vary with genotype.