cross-section diagram of a wheat kernel

Wheat Kernel


What is the wheat kernel?

The wheat kernel, or wheat berry, is the grain portion of the wheat plant and the source of flour. It consists of three main parts—the endosperm, bran and germ—which are usually separated for different flours and uses.

There are over 30,000 wheat varieties, the most common being hard and soft red wheat. White wheat is also popular, while rare varieties include purple, black, brown, or green and gray wheat. The kernel's size generally ranges from 5 to 9 mm long and weighs between 35 to 50 mg.1  Wheat kernels are sold as:

  • Raw
  • Dry
  • Pre-cooked
  • Frozen
  • Flour

Origin

Wheat began as a wild grass, although its exact geographical origin is unknown. Some theories point to ancient Mesopotamia or along the Euphrates and Tigris river as its birthplace. However, most ancient languages include a mention of wheat. The earliest known records of wheat cultivation are by Swiss lake dwellings in 6700 B.C. China began cultivation around 3000 B.C. Early milling practices involved grinding the entire wheat kernel between two large stones.

Wheat has been in the U.S. since colonial times. However, it was during the late 1800s that its cultivation and production took off. Red Wheat varieties were introduced in Kansas by Russian immigrants, and it soon became the staple crop of the American farm land.

Function

The three parts that make up a wheat kernel each have different qualities and nutrients:

Bran
This this outer shell of the wheat kernel and makes up around 14.5 percent of its weight. Milled bran is only used in whole wheat and whole grain flour, or it is sold separately. It consists of trace minerals and a little protein, but primarily insoluble fiber.2

Endosperm
The next layer is the bulk of the kernel, about 83 percent of its total weight. The endosperm is the only part of the kernel used in milling white flour. It has a high portion of protein, along with carbohydrates and iron. The endosperm is also a source of soluble fiber.3

Germ
The germ is the center of the kernel and only 2.5 percent of its weight. This portion is responsible for sprouting the wheat berry. Generally it is removed from flour because its fat content causes rancidity...


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