Gluten viscosity

Gliadins, unlike glutenins, contribute to the viscosity and the extensibility of the gluten and not its strength. 

Rye Proteins. While rye is the only European cereal able to completely replace wheat in bread, rye protein is not as effective as wheat protein. One reason for this is that as much as 80% of the protein in a rye sour dough is soluble compared with 10% of soluble protein in a wheat dough. One factor that inhibits the formation of a gluten-like complex is the 4-7% of pentosans present, which bind water and raise the viscosity of the dough. The crumb structure is then formed from the pentosans in combination with the starch. 

Figure 11. Modification of corn gluten with neutrase 0.5 L (5) viscosity as a function of hydrolysis time.

The magnitude of the above-mentioned increase in viscosity depends on the hydrolysis conditions as well as on the particular corn gluten chosen for the experiments the latter is illustrated by the fact that after a reduction in size (by ball milling) of the corn gluten particles, the viscosities obtained were considerably lower (28). It is therefore to be expected that corn gluten from different sources would yield rather different results. Conclucion... 

Addition of gluten to 6.5-6.6% (w/w) dispersions of different starches at a 1% level ealeulated on dry stareh basis inereased the G of wheat and rye starches, lowered that of maize stareh but did not affeet the modulus of barley, triticale and potato starehes (Lindahl and Eliasson, 1986). G was also found to increase with increasing amounts of gluten (1-4%) added to the wheat starch. Studies on starches with different amylose/amylopectin ratios suggest that gelatinization of amylopectin and not amylose favors a synergistie interaetion with proteins leading to an increase in dispersion viscosity (Chedid and Kokini, 1992 Madeka and Kokini, 1992). 

Proteases are especially of use in production of cookies, crackers, wafers and cakes were a weak gluten stmcture is required. Doughs of weak gluten do not shrink and batters have a low viscosity and do not contain lumps of coagulated gluten. 

Figure 5 Variations with temperature of the steady state viscosity q of gluten from Olympic x Gabo cross line -/17 4- 18/-) in water (filled symbols) and in deuterium dioxide (empty symbols), q was obtained from the recovery curves...

Taylor N.W. and Cluskey, J.E. Wheat gluten and its glutenin component Viscosity, diffusion and sedimentation studies. Am/i. Biochem. Biophys. 97 399-405, 1962. 

Among the additives, the most common are the gums or hydrocolloids. These products have a structure that makes them especially suitable to retain water and increase the viscosity of the masses, in fact are often referred to as thickeners. Their inclusion in the masses improves gas retention and makes less sticky mass. In some articles of bakery, products are called hydrocolloids gluten substitutes. Tara gum finds application in pastry and bakery, imparting smoothness and shape to the dough and makes cutting easier. 

The balance between viscosity and elasticity is close to optimum for wheat gluten protein at the water content used in dough-making. We have seen that the first requirement for a protein in dough to have viscoelastic properties is that its Tg be below the processing (usually ambient) temperature for the water content used. A second requirement for dough in an aerated product is that the molecular weight distribution (MWD) of the protein be optimal. 

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