Basic rheology of bread dough with modified protein content and glutenin-to-gliadin ratios

The uniaxial elongational and shear rheology of doughs varying in either th e protein content or glutenin-to-gliadin ratio were investigated. Increasin g the protein content at constant glutenin-to-gliadin ratio increased the s train-hardening properties of the dough, as shown by increasing elongationa l rupture viscosity and rupture stress. Glutenin and gliadin had a more com plex effect on the elongational properties of the dough. Increased levels o f glutenin increased the rupture viscosity but lowered the rupture strain, while elevated gliadin levels lowered the rupture viscosity but increased t he rupture strain. These observations provide rheological support for the w idely inferred role of gliadin and glutenin in shaping bread dough rheology , namely that gliadin contributes the flow properties, and glutenin contrib utes the elastic or strength properties. The shear and elongational propert ies of the doughs were quite different, reflecting the dissimilar natures o f these two types of flow. Increasing protein content lowered the maximum s hear viscosity, while increasing the glutenin-to-gliadin ratio increased ma ximum shear viscosity. Strong correlations between the results of basic and empirical rheology were found. These basic, or fundamental, rheological me asurements confirmed prior empirical studies and supported baking industry experience, highlighting the potential of basic rheology for bread and whea t research.