Composition of Wheat

The bran is the hard outer covering of the kernel. It is darker in color than the interior of the grain. It is present in whole wheat flour as tiny brown flakes, but it is removed in the milling of white flour. (In the case of whole wheat flour made from white wheat, the bran flakes are a much lighter, creamy white color.)

Bran is high in dietary fiber and also contains B vitamins, fat, protein, and minerals.

The germ is the part of the kernel that becomes the new wheat plant if the kernel is sprouted. It has a high fat content that can quickly become rancid. Therefore, whole wheat flour containing the germ has poor keeping qualities.

Wheat germ is high in nutrients, containing protein, vitamins, and minerals as well as fat.

The endosperm is the white, starchy part of the kernel that remains when the bran and germ are removed. This is the portion of the wheat kernel that is milled into white flour. Depending on its source, the wheat endosperm contains about 68 to 76% starch and 6 to 18% protein. The endosperm also contains small amounts of moisture, fat, sugar, minerals, and other components. These are discussed in more detail when we consider the composition of flour in a later section.