Bread is a staple to a large proportion of the world's population and, at its simplest, it is a dough of wheat flour and yeast bound with water that uses the yeast as a rising agent and which is baked in an oven.

Put this way, it would seem that a bread could be made with any flour. So you might expect Maize breads in the Americas, Rice breads in Asia and Millet or Sorghum breads in Africa. However, this ignores a truly amazing property of wheat and barley grains.

80% of all the protein in wheat and barley is made from two proteins: gliadin and glutenin. These are bound together in the starchy part of the grain, but when wheat flour is kneaded some of the glutenin molecules are released from the starch and these cross-link with one another to form gluten and it's this gluten that gives bread it's amazing properties.

That's why, as you knead bread dough it becomes noticeably smooth and elastic. This is because a network of gluten molecules forms throughout the dough, binding it together. If yeast is added this ferments the sugars in the grain producing bubbles of carbon dioxide. These bubbles are trapped by the gluten network and when the gas is warmed by being heated in an oven it expands, causing the bread to rise. Baking also solidifies the gluten network by coagulation so that the bread sets firm with a smooth texture.

But, just as gluten is critical in the formation of bread in the first place it's also responsible for bread going 'stale' in that gluten traps water molecules as the bread ages.

As a result the gluten in wheat and barley is critical in the formation of breads. Which is not to say that breads can't be made 'gluten free' (rice is common) it's just that they tend to be crumblier and more cake-like than wheat or barley-based breads.

Yet, the adulteration of bread with the inclusion of all manner of substances ranging from chalk to sawdust is an ancient practice. In the end it emerges that you can typically add 20% of something else to a bread dough and it will still rise and have all the properties of a traditional loaf.

This can be very important for a subsistence or even a largely vegetarian diet as, if you mix ground beans with your wheat flour you get all the essential amino acids in your diet from just bread. This is why the UN is promoting the use of locally-grown millet or sorghum in Africa for this very purpose. For similar reasons, black-eyed pea flour is used in Liberia.

A number of starch or flour sources can be used to add to a wheat flour bread and these include: pea flour, millet flour, sorghum flour, ground nuts, linden leaf flour, black eyed pea flour (indeed, any ground beans, potato starch, rice flour (but add a little cornstarch to stabilize), maize flour and cassava flour.

The recipe below is for a maize flour bread, but you can use the quantities to adapt for any kind of mixed flour loaf:

Maize Flour Bread
Ingredients:
140g maize flour
560g strong bread flour
25g yeast
1 tbsp white sugar
60ml lukewarm water
350ml water (to bring the dough together)
1 tbsp salt
1 tbsp butter, melted and allow to cool

Method:
Stir the yeast and sugar into the 60ml lukewarm water and set aside in a warm place for about 10 minutes to activate the yeast.

Combine the maize flour, bread flour (wheat flour) and salt together in a bowl then combine the melted butter with the yeast mix. Form a well in the flour and pour the yeast mix into this. Stir well then add the remaining water a little at a time, until you have a smooth dough. Turn the dough onto a lightly-floured surface and knead thoroughly for at least 5 minutes (remember that it's this kneading that gives any bread it's bread-like properties). Don't skimp on the kneading as you will need to release more gluten because of the maize flour added here.

Roll the dough into a ball, placed in a lightly-greased bowl (turning to coat in the oil) then cover with a cloth and set aside in a warm spot to rise for at least 75 minutes, or until doubled in size. Knock the dough back (remove the air from it by punching) and knead well for 5 minutes then return to the bowl, cover and set aside to rise for a further 45 minutes.

Knock the dough back once more then divide into 2 equal parts. Knead each piece very thoroughly to remove any trapped air then press each dough half into separate 500g loaf tins. Press down well into the base of the tin then cover and set aside in a warm place to raise for at least 45 minutes (the dough should have risen over the top of the tin by this time).

When well risen place the loaves in an oven pre-heated to 210C and bake for about 25 minutes, or until the loaf is golden brown and the base sounds hollow when tapped.

Allow the loaves to cool slightly before turning onto a wire rack to cool completely.

As long as you knead well at each stage these loaves work every time and you can replace the maize flour with just about any kind of ground ingredient you want.