Gluten in baking

You will often hear bakers and food teachers talking about gluten, so what exactly is gluten And where is it found? 

Gluten is a protein formed when water is added to wheat flour to make a dough. It is actually formed from glutenin and gliadin the two proteins in wheat flour. It is needed in many ways in baking.  In the most part it is the reason that mixtures with wheat flour such as cakes and pastries hold their shapes.  A raw mixture of dough is pliable but when it is cooked becomes rigid. The gluten in the dough, being a protein, sets once the temperature rises to over 60⁰C - 65⁰C.  This is also known as denaturation of protein because it is non reversible.  Once the dough is set it remains so. Gluten is responsible for a flour dough holding its cooked shape.

Starch, the other main component of wheat flour dextrinises on cooking and provides the characteristic golden colour of bakes goods.  When sugar is also present in the mixture such as in cakes the golden tones are deeper and richer due to caramelisation.

Have a look at gluten, Where can we actually see it?  If you mix Strong flour with water and ‘knead’ it the proteins in the wheat flour will form gluten.  Strong flour (Bread flour)  can contain up to 14g or 15g protein per 100g as opposed to around 9g per 100g in white cake flour.

 

The dough formed can be ‘washed’ in cold water to remove the starch.   The starch grains are suspended in the water and wash away as white milky water.  Gradually the gluten can be seen as a grey, stretchy mass.  The more starch is removed the stronger and more elastic the remaining gluten.  You can cook small portions of the gluten.  On heating any remaining water turns to steam and puffs up the gluten.  The outer crust of gluten sets as the proteins are denatured by the heat.  It takes longer for the inside to set.  The structure will collapse after cooking as steam softens the crust.

The picture below shows uncooked gluten:


 

The picture below shows cooked gluten.


 

Where might you see gluten when you are cooking?

When you make more advanced pastries such as puff pastry, or Danish pastry dough you will see how gluten can help form layers that give the characteristic flaky light pastry

When you make bread the kneading action used during preparation is responsible for developing gluten in the dough.  Gluten is ‘developed’ during this important stage.

When you prepare shortcrust pastry or shortbread the reverse is seen.  The gluten is not required to be ‘developed’, in fact it is the action of rubbing in fat that prevents water long strands of gluten forming and keeps the pastry or biscuits crumbly and light in texture.

How ingredients work is part of food science.  I hope you found it helpful to read about the role of gluten when cooking.