Bread is a product of baking a mixture of flour, water, salt, yeast and other ingredients. The basic procedure involves mixing of ingredients until it’s converted into dough, followed by baking the dough into a loaf. The aim of the bread making process is to produce dough that will rise easily and have the properties required to make good bread for the consumer. To make good bread, dough made by any process must be extensible and will stretch when pulled. It must also be elastic, that is, have strength to hold the gases produced while rising, and stable enough to hold its shape and cell structure.
Sieving of the flour is done to remove contaminants and to aerate the flour. The purpose of mixing the dough is to distribute the yeast cells. Two proteins present in flour; gliadin and glutenin form gluten when mixed with water. Gluten is essential for breadmaking and influences the mixing, kneading and baking properties of the dough.
Methods of Bread making
There are two methods of bread making; straight dough method and sponge & dough method.
- Straight dough is a single mix process of making bread. The dough is made by combining all ingredients together and combined in one mixing session. After mixing, a bulk fermentation rest of about 1 hour occurs before division.
- The sponge & dough method is a two step bread making process. In the first step a sponge is made and is allowed to ferment for a period of time and in the second step the sponge is added to the final doughs’ ingredients.
The dough produced by the straight dough method results in breads with coarse grain texture and the crumb is not soft as that produced from the sponge & dough method. In bread making the ingredients used are; bakers flour, salt, instant yeast, sugar, fat and water.
Proteins are an important component of the flour. These include the classes of proteins glutenins and gliadins, which are huge molecules built up of a large number of amino acids. They are collectively known as gluten. As soon as water is added to the mixture, the proteins are able to line up with each other and interact. They can form hydrogen bonds and disulphide crosslinks between their chains, eventually forming a giant gluten network throughout the dough. Kneading the dough helps these proteins uncoil and interact with each other more strongly thus strengthening the network.
Salt helps to strengthen the gluten network, making the dough more elastic and adding flavour to the final bread.
Yeast contains enzymes that are able to break down the starch in the flour into sugars; firstly the amylase to breakdown the starch to maltose, and then using maltase to breakdown maltose to glucose. This glucose acts as food for the yeast, and it metabolizes it to produce carbon dioxide and ethanol. Gluten networks help to trap the carbon dioxide. The sugar produced by this process isn’t all metabolized by the yeast however it gets involved in the maillard reaction. These reactions produce a whole range of products which can add flavour to the bread and also help to form the brown crust of the bread.
Fats weaken the gluten network, giving a softer bread. It also stabilizes gas bubbles, increasing loaf volume.
Sugar is used by yeast for fermentation. It also enhances bread flavour and gives the crust a golden colour. In addition to that, it improves the crumb texture of the bread. It is important to note that too little or too much sugar in the dough can slow down yeast activity.