Parts of the wheat kernel

Whole wheat flours contain all three major parts of the wheat kernel,

Parts of a wheat kernal image

  • Bran is the hard, brownish outer protective skin of the grain. It surrounds 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 layer is the largest portion of the bran, constituting 75% or more of its dry weight.
  • 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.
  • 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 and vitamin E content is found in the germ.