Dough flour

Many industrially important fluids cannot be described in simple terms. Viscoelastic fluids are prominent offenders. These fluids exhibit memory, flowing when subjected to a stress, but recovering part of their deformation when the stress is removed. Polymer melts and flour dough are typical examples. Both the shear stresses and the normal stresses depend on the history of the fluid. Even the simplest constitutive equations are complex, as exemplified by the Oldroyd expression for shear stress at low shear rates ... 

Flour Bleaching Agents and Bread Improvers. Freshly milled flour contains carotenoid pigments that cause the flour to have a yellow color. In addition, when the flour is made into dough the product is sticky and unmanageable. As the flour ages, a natural process takes place which turns the flour white and improves its baking qualities. Because the natural process takes quite a bit of time, additives are used to speed up the process. 

Normal Stress (Weissenberg Effect). Many viscoelastic fluids flow in a direction normal (perpendicular) to the direction of shear stress in steady-state shear (21,90). Examples of the effect include flour dough climbing up a beater, polymer solutions climbing up the inner cylinder in a concentric cylinder viscometer, and paints forcing apart the cone and plate of a cone—plate viscometer. The normal stress effect has been put to practical use in certain screwless extmders designed in a cone—plate or plate—plate configuration, where the polymer enters at the periphery and exits at the axis. 

Oilseed proteins are used as food ingredients at concentrations of 1—2% to nearly 100%. At low concentrations, the proteins are added primarily for their functional properties, eg, emulsification, fat absorption, water absorption, texture, dough formation, adhesion, cohesion, elasticity, film formation, and aeration (86) (see Food processing). Because of high protein contents, textured flours and concentrates are used as the principal ingredients of some meat substitutes. 

Milk and Milk Replacers. White pan bread was long made with about 3—4% nonfat dry milk (NEDM) in the United States, for reasons of enhanced nutrition, increased dough absorption, improved cmst color, fermentation buffering, and better flavor. Eor some years, however, sharply increased milk prices have led to a decline in its use in breadmaking. Many bakers have turned to the use of milk replacers to control the costs of their products, and these ingredients are now commonly utilized. Milk replacers were designed to dupHcate some of the functions and nutrition of milk. These blends may contain soy flour or cereals, with whey, buttermilk soHds, sodium or calcium caseinate, or NEDM. Milk replacers or NEDM used in bread dough amount to about 1—2%, based on flour. 

Eggs. Eggs are not used much in breadmaking, except for specialty egg breads. Egg whites are occasionally used on the surface of hard roUs to impart a crispy cmst. Yeast-leavened sweet doughs or danish doughs often contain egg, up to 20%, based on flour, to achieve richness and to influence color and flavor. Some bakery foods, eg, sweet goods, croissants, and puff pastry, are often washed with egg wash (a mixture of egg and water or milk)... 

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