Gluten viscoelasticity

The proteins that are of most interest in baking are the proteins from wheat. The wheat that is normally used is Triticum aestivum not Triticum durum which is used to make pasta. The distinguishing property of wheat proteins is that some of them can develop into the viscoelastic mass known as gluten. The only other grain that has... 

Thermo-mechanical analysis (TMA)26 and DMTA292 have been used to study the viscoelastic properties of bread, a composite two-phase system. The moisture dependence of Tg was similar to that of pure amorphous starch and gluten.242,282 293-295 At the moisture content of bread, water exerts its full plasticization effect on the composite polymer matrix, reducing the effective Tg to about -10° to - 12°C,26,292 well below normal shelf life storage temperatures of this product. 

Wheat starch is low in protein, ash and fiber, and contains no residual sulfites. Sulfur dioxide is detrimental to the viscoelastic character of wheat gluten and is not used in the commercial production of wheat starch.28,323 The protein content of ten samples of unmodified and modified wheat starches ranged from 0.06-0.22%.28 A 0.23% protein (0.0404% nitrogen) level in wheat starch essentially indicates a gluten-free starch, as confirmed by an enzyme immunoassay.324 That purity of wheat starch is important in diets for celiac individuals. Wheat starch-based, gluten-free flour products were not harmful in the treatment of celiac sprue and dermatitis herpetiformis,325 although traces of an immunoreactive gliadin can be found in wheat starch.326... 

Wheat Gluten occurs as a cream to light tan, free-flowing powder. It is the water-insoluble complex protein obtained by water extraction of wheat or wheat flour. It is soluble in alkalies, and partly soluble in alcohol and dilute acids. Vital Wheat Gluten is characterized by high viscoelasticity when hydrated, while Devitalized Wheat Gluten has lost this character because of denaturation by heat. 

The peculiar viscoelastic properties of wheat dough are the result of the presence of a three-dimensional network of gluten proteins. The network is formed by thiol-disulfide exchange reactions among gluten proteins. Peptide disulfides can interfere in a thiol-disulfide exchange system by reacting with a protein (PR)-thiol to liberate a peptide (R)-thiol and form a mixed disulfide, as follows ... 

Gliadin. Gliadin is that portion of the gluten proteins that is soluble in 70% aqueous ethanol. It comprises approximately 35 to 40% of the flour proteins. Gliadin imparts the viscous component to the viscoelastic properties of gluten. 

Conclusions Wheat Gluten Proteins and Dough Viscoelasticity... 

It is also important to remember that wheat gluten and dough are complex materials, consisting not only of protein and water, but also starch-, lipid-, water- and salt-soluble proteins and smaller carbohydrates, and so on. The properties of these materials and their interactions with the gluten proteins are poorly understood but can be expected to also influence the viscoelastic properties. The challenge therefore is to understand gluten structure at the molecular level and how this structure interacts... 

Quinoa flour does not have good baking properties like wheat gluten proteins. The wheat proteins are able to form a viscoelastic network when flour is mixed with water to form dough, and these viscoelastic properties allow the use of wheat to produce bread and other processed foods (Shewry et al., 2002). Quinoa bread has been made by including 10% of wheat flour (Chauhan et al., 1992a,b). However, the enzyme... 

In the present work the effect of temperature on the rheological behaviour of wheat gluten in D20 is compared to that in water. The viscoelastic response was studied in shear by combining dynamical measurements and creep and recovery tests, in order to encompass a large timescale. 

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