Optimize baking to reduce waste, costs.

Scientists at the U.K.'s Institute of Food Research (IFR) are unraveling the mysteries of dough. Their work will help reduce wastage and the use of additives in the bakery industry, as well as improve the bread-making quality of flour.

A major problem faced by the bread-making industry is that the quality of different batches of flour can only be judged by using them to bake a loaf. Variability among flour batches can lead to costly wastage. This is a particular problem with European wheat, where the changeable climate can affect the bread-making properties of the flour.

Another problem is that dough in a loaf tin can collapse if the tin is knocked or banged before cooking. So additives are included in the dough to stabilize it and prevent it from collapsing. One of the goals of IFR scientists is to help reduce the need for these additives. To do this, they are trying to understand how the various components of the dough behave and interact with each other. The main ingredient of bread dough is flour. This is mostly starch, but also contains gluten. We know that the gluten is crucial for bread-making quality, as it helps make the dough stretchy and elastic.

The dough is mixed and must then be kneaded. The physical and biological changes caused by kneading are not fully understood, but they seem to make the dough more elastic. Air also seems to be crucial to the process. If the dough is kneaded in an atmosphere containing nitrogen instead of air, the resulting loaf is of poorer quality.

In baking, yeast is added to the dough and produces carbon dioxide, which makes the loaf rise. Leaving the dough to "prove" allows the gas bubbles produced by the yeast to expand. So bread dough is really a foam--a collection of bubbles.

If the gluten is too strong, the loaf won't rise, as the gas bubbles can't form properly in the dough. But if the gluten isn't strong enough, the bubbles become too large and the loaf ends up with a hole in its middle. The dough is then cooked in a hot oven, where the foam sets. This traps the gas bubbles within the loaf.

Another goal of researchers is to better understand how the environment affects the bread-making qualities of wheat flour. The type and amount of essential proteins in the flour vary, depending on the environmental conditions in which the wheat was grown.

Further information. Clare Mills, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, United Kingdom; phone: [phone]; fax: [phone]; email: [e-mail].