Parts of the Wheat Kernel

Whole grain wheat flours contain all three major parts of the wheat kernel – the bran, the endosperm and the germ.

Bran

Bran is the hard, brownish outer protective skin of the grain. It surrounds the germ and the endosperm, protecting the grain from weather, insects, mold and bacteria.
The bran consists of 7 layers. The bran layers are a concentrated source of dietary fiber.
The aleurone is the layer of cells between the bran and the endosperm.
The aleurone layer is a concentrated source of vitamins, minerals and other nutrients.

The endosperm is the inner part of the grain. It supplies food to the growing seedling.
The main nutrients in the endosperm are protein and carbohydrate. About 50 to 75% of the endosperm is starch. It also contains storage proteins, typically 8 to 18%. Relatively few vitamins, minerals, fiber or phytochemicals are found in the endosperm.
White flour is produced from the endosperm.
Whole wheat flour in Canada includes the endosperm and bran portions of the wheat kernel.

The germ contains the plant embryo. It typically accounts for about 2 to 3% of the wheat's dry weight.
Most of the wheat kernel’s fat (comprised of essential fatty acids), B vitamins and vitamin E content are found in the germ.
The germ portion can be removed in a Canadian whole wheat flour.