Wheat Flour Quality Assessment by Fundamental Non-Linear Rheological Methods: A Critical Review

Abstract

Wheat quality assessment involves physical, physicochemical, chemical, and sensory characterization of wheat kernels and the resulting wheat flour, dough, and bread. The physical tests conducted on wheat flour dough are mostly based on empirical methods. Empirical methods have been useful in industry and research to relate wheat flour quality to baking performance. However, these methods have the disadvantage of providing data in arbitrary units, which makes the fundamental interpretation of results difficult. Therefore, this review focuses on the use of fundamental rheological methods to determine wheat flour quality in terms of processing performance. During the transition from wheat flour to bread, wheat flour dough is mostly exposed to large deformations, and the quality of wheat flour determines its response to these large deformations and its baking quality. For this reason, this review only focuses on the application of fundamental rheological tests that are conducted in the non-linear viscoelastic region where wheat flour dough experiences large deformations.

Impact of Wet Gluten Content on Non-Linear Viscoelastic Properties of Wheat Flour Doughs

“…This difference in the viscoelastic behaviors of HRW and SRW wheat flours determined in the linear region conflicted with the Farinograph data as Farinograms indicated a weaker network for SRW wheat flour (Figure 1a,b). This is plausible as the deformations applied in the Farinograph mixing are large, complex, and non-uniform, while LAOS sweeps apply small and uniform deformations in the linear region (Yazar, 2023). Thus, for the hard and soft wheat flours tested in this study, the differences in the gluten composition became prominent under small deformations, while the difference in the gluten content dominated the viscoelastic behavior under large deformations.…”

“…When the frequency of deformation further decreased to 1 rad/s, the magnitude of e3/e1 for SRW wheat flour dough started to decrease at the strain amplitude of 170%, while no decrease was observed in the strain stiffening behavior of HRW wheat flour dough up to the strain amplitude of 200% (Figure 6a). The change found in the e3/e1 values elucidated the impact of deformation frequency on the strain stiffening behavior of wheat flour dough (Yazar, 2023). Due to its viscoelastic nature, wheat flour dough is known to partially recover after being stretched rapidly, followed by the sudden removal of the force (Delcour and Hoseney, 2010).…”

“…The differences in gluten content, gluten composition (i.e., gliadin to glutenin ratio), and gluten quality in different wheat flours have been suggested as the origin of textural differences between a wide variety of baked products (Bonilla et al, 2022). Therefore, gluten quality and quantity characterization constitute a major part of wheat flour quality assessment in terms of baking performance (Yazar, 2023).…”

“…Empirical methods have demonstrated their usefulness in industry and research to relate the rheological behavior of dough to baking performance, they have the disadvantage of providing data in arbitrary units, which makes the fundamental interpretation of results difficult (Campanella and Peleg, 2002;Dobraszczyk and Morgenstern, 2003). Therefore, fundamental rheological methods, that enable an accurate comparison and interpretation of the obtained data, have gained attention for the characterization of dough's viscoelastic properties (Yazar and Demirkesen, 2023;Yazar, 2023). Fundamental rheological tests are classified as small deformation and large deformation tests based on the magnitude of the applied deformation (Duvarcı et al, 2019).…”

“…Fundamental rheological tests are classified as small deformation and large deformation tests based on the magnitude of the applied deformation (Duvarcı et al, 2019). Small deformation tests show little relationship with end-use performance as they are generally conducted under deformation conditions inappropriate for breadmaking (Amemiya and Menjivar, 1992;Dobraszczyk and Morgenstern, 2003;Yazar, 2023). Studies have shown that small strain rheology was more advantageous for understanding molecular interactions and microstructure, while fundamental large strain rheology could be used to differentiate different types of wheat flours as these tests can approach the deformations dough experiences during processing (Kim et al, 2008).…”