Stress Relaxation Behavior of Wheat Dough, Gluten, and Gluten Protein Fractions

Abstract

Cereal Chem. 80(3):333-338Relaxation behavior was measured for dough, gluten and gluten protein fractions obtained from the U.K. biscuitmaking flour, Riband, and the U.K. breadmaking flour, Hereward. The relaxation spectrum, in which relaxation times (t) are related to polymer molecular size, for dough showed a broad molecular size distribution, with two relaxation processes: a major peak at short times and a second peak at times longer than 10 sec, which is thought to correspond to network structure, and which may be attributed to entanglements and physical cross-links of polymers. Relaxation spectra of glutens were similar to those for the corresponding doughs from both flours. Hereward gluten clearly showed a much more pronounced second peak in relaxation spectrum and higher relaxation modulus than Riband gluten at the same water content. In the gluten protein fractions, gliadin and acetic acid soluble glutenin only showed the first relaxation process, but gel protein clearly showed both the first and second relaxation processes. The results show that the relaxation properties of dough depend on its gluten protein and that gel protein is responsible for the network structure for dough and gluten.

Use of the Stress-Relaxation and Dynamic Tests to Evaluate the Viscoelastic Properties of Dough from Soft Wheat Cultivars

“…G0 showed a strong correlation with protein (r=0.984), which could be reflected in the greater strength of gluten, thereby a high resistance upon deformation. A second correlation of G0 was with wet gluten (r=0.987), which probably is due to the fact that a greater amount of gluten causes greater resistance to deformation, and this is in agreement the study carried out by (Li et al, (2003). Finally, the last correlation of G0 was with falling number (r=0.986).…”

“…In general, variation of values of τ (range 0.33 s to 0.41 s) was probably attributed at the content and type of protein, and moisture content of the wheat cultivar. This has been observed in several investigations, where it has been found that moisture and gluten properties (such as gluten strength) affect the parameters of this test (Fu et al, 1997;Larsson & Eliasson, 1996a;Li et al, 2003;Yadav et al, 2005).…”

“…It is observed that all curves present a single maximum stress coinciding with Rao et al (2000). Li et al (2003) found that relaxation process occur in two steps: the first, correspond at the increase of distribution of protein polymers short chain (gliadin and glutenins of low molecular weight). The second peak corresponds at the protein polymers of large chain like glutenins of high molecular weight.…”

“…After placing the sample in the rheometer, it was allowed to rest for a period of 20 min before the test. Based on preliminary tests and some researches (Li et al, 2003;Rao et al, 2000;, stress relxation was measured at intervals of 0.1 s applying a 15% shear strain for 30 min at a controlled temperature of 25ºC operating in shear stress mode. The parameters determined were maximum stress at 15% strain (G0) and the relaxation time (τ).…”

Quality Changes of Fresh Dumpling Wrappers at Room Temperature

“…And other ingredients such as fat, sugar, starch and water are contained in the skeleton, which makes the gluten with elasticity and plasticity (Yu et al, 2010). Gluten proteins confer dough rheological properties such as water retention, dough adhesion and viscoelastic properties (Li et al, 2003). The mechanism of the increase in hardness during dough formation is not well understood but is generally believed to be the result of optimization of the protein interaction in the dough.…”