Proteins and Baking Quality of Three Sudanese Wheat Cultivars I. The Relationship Between Protein Soluble Fractions and Breadmaking Properties

Abstract

The objective of this research was to study the proteins of three Sudanese wheat cultivars and their relationship to breadmaking properties. The Sudanese cultivars (Elneelain, Debaira, and Wadi Elneel) were compared with an Australian bread wheat cultivar. Baking test, farinograph characteristics, sedimentation value, gluten and gluten index were determined in wheat flours of 68% extraction rate. Wadi Elneel cultivar showed a better breadmaking quality than Elneelain and Debaira. Samples of whole wheat flours from the three Sudanese wheat cultivars and the Australian wheat were fractionated by a modified Osborne fractionation procedure into five solubility fractions: (i) the water-soluble albumins, (ii) the salt-soluble globulins, (iii) the aqueous alcohol-soluble gliadins, (iv) the acetic acid-soluble glutenins, and (v) the residue-glutenin fraction. The residue glutenin, calculated on flour basis, showed significant positive correlations (P≤0.05) with total protein, wet gluten, dry gluten, sedimentation value, gluten index and specific loaf volume. The residue glutenin, on total protein basis, showed significant positive correlations (P≤0.05) with total protein, gluten index and specific loaf volume. On the other hand, the soluble glutenin, calculated on flour basis, showed significant positive correlations (P≤0.05) with only water absorption and farinograph development time. The residue glutenin was found to be a fundamental factor determining breadmaking quality of wheat. The gluten indices of the Sudanese wheat cultivars were high, indicating good breadmaking quality, but according to other results of this study, the Sudanese wheat cultivars are of poor quality. Therefore, gluten index, as a breadmaking quality parameter, may not be applicable to the Sudanese wheat.