Effect of the chemical and physical properties of wheat starch granules on the rheological properties of wheat flour dough

The effects of the chemical and physical properties of wheat starch granules on the rheological properties of wheat flour dough were investigated. First, the drying methods used to obtain starch fractions (air, freeze, and commercially dried) were investigated to determine if the methods influenced the rheological properties of the starch fractions. Analysis of the reconstituted doughs (starch, gluten, and water solubles) indicated that the commercial starch fractions affected more mixing curve parameters than the other two starch fractions, and chemical analysis determined that the commercially obtained sample contained higher amounts of damaged starch and protein.;Next, commercially available wheat starch fractions were studied for the relationship of differences to the rheological properties of the starch fractions in a wheat dough system. Analysis of reconstituted doughs and chemical and physical analysis of the starch fractions indicated the percentage of damaged starch, the amount of protein, and the percentages of A and B-type starch granules appeared to relate to many mixing curve parameters.;Additionally, the rate of moisture absorption and the effect of starch protein of a large and small starch granule fractions used in reconstituted doughs were studied. The rate of moisture absorption revealed that the small granule starch fraction absorbed more water and over a longer period of time compared to the large granule fraction. Reconstitutions of starch (and protein extracted starch) and gluten revealed that the protein content of the starch fraction does not influence the rheological properties of the reconstituted doughs.;Also, starch granule fractions were added to a base flour before mixing and to a flour dough after the dough had developed (at peak) and allowed to rest to determine if the starch influenced the mixing properties of a dough. The results indicated that the starch added to the flour prior to mixing had the greatest impact on influencing the mixing characteristics of a dough.;Finally, the differences in the rheological properties of starch granule fractions are likely influenced by the damaged starch content of the starch fractions.