The Viscoelastic Properties of Wheat Flour Doughs

Abstract

It should be evident that cereal scientists need to be able to measure and understand the fundamental mechanical properties of wheat flour doughs. Restated more precisely, the goal is to understand the relationships between the forces acting on dough, its subsequent deformation, and time. This goal has been the impetus for a great deal of research over the past 60 years. Several recent reviews (Hlynka, 1970;Hibberd and Parker, 1975b;Baird, 1983;Faubion et al. 1985; Faubion and Faridi, 1986) present the rationale for applying fundamental rheological tests to investigate the mechanical properties of dough. Bushuk (1985) sums up this rationale concisely:In breadmaking, the dough undergoes some type of deformation in every phase of the process. During mixing, dough undergoes extreme deformations beyond the rupture limits; during fermentation the deformations are much smaller; during sheeting and shaping, deformations are of an intermediate level; and finally during proofing and baking, dough is subjected to more deformations. Accordingly. the application of rheological concepts to the behavior of doughs seems a natural requirement of research on the interrelationships among flour composition. added ingredients, process parameters and the characteristics of the loaf of bread.The process of generating the data necessary to characterize the rheology of dough is far from complete, because of the difficulty of determining the material properties of systems as complex as wheat flour doughs. If determining the material properties were simple, most (if not all) of the required information would now be in hand. Of the large body of research that exists on the rheological properties of wheat flour doughs, the great portion is empirical rather than fundamental in nature. It is important to bear in mind, however, Contribution No. 89-32S-B from the Kansas Agricultural Experiment Station. 29 H. Faridi et al. (eds.), Dough Rheology and Baked Product Texture

A Farinograph Study on Dough Characteristics of Mixtures of Wheat Flour and Potato Starches from Different Cultivars

“…A similar trend was also observed for the dough characteristics of mixtures of wheat flour with different protein contents and sago starch (Zaidul et al, 2004). Faubion and Hoseney (1989) reported that the water-binding capacity of starch granules has been postulated to have a strong effect on dough rheology. It is evident that the adsorption depends not only on the types of protein but also on the percent of starch.…”

“…It is evident that the adsorption depends not only on the types of protein but also on the percent of starch. However, higher absorption indicates that more water is required to reach a desired consistency in a commercial process, but does not indicate the exact amount (Faubion and Hoseney, 1989). In addition to water absorption, the shape of the farinogram is characterised by the flour.…”

“…Our results in Figure 3 also suggested that potato starch would not interact readily with gluten to form elastic dough. Stability, in general, gives some indication of the tolerance of mixing the flour (Faubion and Hoseney, 1989). This means that with increase of potato starch in the mixture decreased the tolerance, from the trends in Figure 4.…”

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

“…Wheat dough is classified as viscoelastic material (Faubion & Hoseney, 1990) which has elastic and viscous characteristics conferred by gluten. Gluten network is formed by hydrophobic interactions between water and protein polymers of the flour (mainly glutenins and gliadins).…”

“…Rheology of wheat dough is broad, and the tests utilized are diverse. Initially, empirical tests were more used than the fundamental tests, but disadvantages were seen such as: dependence on the instrument, the form and quantity of the sample utilized and lack of theoretical basis (Faubion & Hoseney, 1990), which led to the development of fundamental tests. The most important fundamental viscoelastic tests utilized for wheat dough are the force-deformation ratio, creep test, the dynamic test and stress-relaxation test (Mohsenin, 1978).…”