Although the gluten content of flour is talked about, in reality gluten does not exist as such in flour. Instead there are two major protein components present in flour, which when combined with water form Gluten.
These two proteins are called Gliadin and Glutenin and each of these proteins have different attributes which ultimately give Gluten its properties. Gliadin and Glutenin are only produced by cereal plants, with wheat containing the highest levels of these proteins when compared to other cereal grains, i.e. Rye or Barley.
- Gliadin is very sticky when wet and very extensible and imparts adhesive properties to gluten.
- Glutenin is a large and complex protein which gives dough strength and elasticity.
When water is added to flour and mixed, these proteins absorb water, otherwise known as hydrating. Gliadin and Glutenin then combine to form the protein called GLUTEN.
Gluten is a tough, rubbery and elastic substance, which has the capacity to stretch and rise due to the action of baking powder or yeast. When flour is mixed with water, the gluten swells to form a continuous network of fine strands.
After two hours rising gluten strands form a lattice as the dough reaches the required size. (Electron microscope view).
This network forms the structure of bread dough and is responsible for the texture of bread as we know it. This is because gluten has four important properties:
- it absorbs twice its weight in water
- it is sticky
- it is extensible; this means it will stretch when pulled
- it is elastic; when stretched it will return to near its original size.
These four properties of gluten in dough make wheat suitable for bread baking.