This dough may be stretched in two directions and form sheets or films, or it may be stretched in all directions under the pressure of expanding gas and form bubbles as does bubble gum. Gluten from strong flour is more perfect colloidal gel, as shown by its greater hydration capacity than gluten from soft flour.
Baking quality of flour depends on both the quantity and quality of gluten that can be formed from it.
Yeats breads are prepared from soft dough using hard wheat flours to form gluten structure that is strong and elastic. The structure may contain starch and sugar or other ingredients such as eggs and fat. The yeast is responsible for the production of CO2 within the gluten structure.
The wet gluten is a cohesive, elastic mass that expands greatly on baking to form a light porous ball. Baked gluten contains about 85% protein, 8% lipids and variable amounts of starch depending on the thoroughness of washing.
Wheat starch does not form elastic films as does gluten; rather, the moistened starch, when heated forms a paste and stiffens or more correctly gelatinizes.
Baking the gluten shows that it expands greatly as the steam within it expands and that it coagulates when heated to form the structure of the baked product.
Generally, cookies are produced using soft wheat flour that ahs relatively weak gluten strength (e.g. pastry flour, a blend of soft red and soft wheat).
The cookies usually consist of high fat and sugar contents, and low moisture content.
The importance of gluten in flour for baking
