Nutrition Meets Food Science

Whole Wheat Flour Bread is Difficult to Make

Bread has been made for a long time and is not very difficult. All one requires is wheat flour, yeast and water with maybe some salt. The ingredients are mixed into a nice dough and the dough is allowed to leaven. Once becomes sufficiently large it is put in the oven to bake it. When flour is mixed with water, the proteins in flour form gluten, which is elastic and can stretch. When the yeast in the dough starts to ferment, it forms gas and carbon dioxide. Tiny yeast cells are distributed in the dough in literally a million places. Each forms a gas bubble growing and increasing the dough volume since gluten is elastic. The entire dough increases in volume as it leavens. When it is baked at high temperature, the structure with tiny gas bubbles hardens as moisture leaves and gluten forms a nice porous structure, which can be easily seen when bread is sliced.

When one tries to make multigrain or whole-wheat flour bread, some differences are introduced in flour and consequently in the dough makeup which will make it somewhat difficult to make soft springy bread which is formed when refined wheat flour is used.

Wheat kernels have three parts namely, bran, endosperm and germ. Bran is the outer layer, which is mostly dietary fibre while germ contains some fat, while the endosperm is mostly protein and carbs. When refined flour is prepared the bran and germ are removed by processing, leaving mostly the endosperm. Gluten is present in an endosperm and is responsible for forming a nice elastic network entrapping tiny gas bubbles which grow as the dough is kept for leavening.

When whole-wheat flour containing bran and germ is used for the dough the gluten network is not continuous but is disrupted by bran and germ particles so the leavening does not take place effectively and volume is lower.

There are also several other difficulties. While refined flour hydrates easily when water is added to make dough, bran and germ particles having dietary fibre and other components, take much longer and more water to hydrate adequately.

It is not just whole wheat, but multigrain and other variations also would have difficulty in getting good leavening in a short time. The wheat type also makes difference. Bread needs wheat flour with higher protein content. With lower protein, gluten is weaker and leavening is more difficult. There are differences due to particle size. Refined flour usually is finer and whole-wheat flour is coarser. Bigger particles make it not only difficult to hydrate but also to form a good gluten network. It is possible to get finer whole-wheat flour but takes more grinding.

When millet is used this also interferes with gluten formation and so the rise of dough is less or more difficult. However, despite whole-wheat flour bread looking brownish, and less soft, people prefer it because of the health benefits it provides. Not only there are benefits of dietary fibre, which resist the onset of diabetes, and heart disease, the presence of vitamins and minerals makes it more nutritious.

In the market, there are many different types of bread available; some are called whole wheat bread, and some are brown bread. Recently, FSSAI defined whole wheat bread as one containing at least 75% whole-wheat flour and brown bread containing at least 50% whole-wheat flour. This will come into force in May 2023. Consumers should read labels properly to choose what they want and not get confused by terms and claims, which sometimes they do not understand or may be misleading.

Dr Jagadish Pai

Executive Director - PFNDAI

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