Coloured scanning electron micrograph (SEM) of White bread surface. Shown here is a slice of white sandwich bread, revealing the large airspaces that develop as a result of the action of the yeast. White bread made from wheat flour that has the bran and germ removed through a process known as milling. Milling gives white flour a longer shelf life by removing the bran which contains oil, allowing products to survive storage times. In addition, the flour used in white bread is often bleached using potassium bromate or chlorine dioxide gas to remove any slight yellow colour and make its baking properties more predictable. Magnification: x6 when shortest axis printed at 25 millimetres.