A Kernel of Wheat




  • K ernel . . . sometimes called the wheat berry. The kernel is the seed from which the wheat plant grows. Each tiny seed contains three distinct parts that are separated during the milling process to produce flour.
  • E ndosperm . . . about 83% of the kernel weight and the source of white Endosperm flour. The endosperm contains the greatest share of protein, carbohydrates, and iron, as well as B-vitamins such as riboflavin, niacin.  It is also a source of soluble fiber.
  • B ran . . . about 14% of the kernel weight. Bran is included in whole wheat flour and can also be bought separately. The bran contains a small amount of protein, trace minerals, and dietary fiber – primarily insoluble.
  • G erm . . about 2.5% of the kernel weight. The germ is the embryo or sprouting section of the seed. It is often separated from flour because the fat content (10%) limits shelf life. The germ contains minimal quantities of high quality protein and a greater share of B-complex vitamins and trace minerals. Wheat germ is part of whole wheat flour and can be purchased separately.
Wheat and Flour Testing -Introduction        

Wheat and flour specifications are communications between buyers and sellers. Standard methods have been developed to promote an orderly marketplace. The wheat and flour tests described in this section are standardized testing procedures commonly used for quality control purposes. Results from these tests have a direct relationship to finished product quality.

       Wheat and flour specifications commonly require basic tests for moisture content, protein content, and falling number. Ash content is another important specification for flour. Flour color and single kernel characterization system (SKCS) are physical tests that may be specified by wheat processors. Milling is the separation of wheat into flour and bran. Laboratory milling is used to evaluate the milling performance of wheat and to produce flour for laboratory tests.

  Several tests evaluate dough and gluten strength properties. The Farinograph and Mixograph measure the resistance of dough to mixing. The Extensigraph measures the resistance of dough to stretching. The Alveograph measures the resistance of a bubble of dough to expansion.

         The main components of flour are starch and protein. Specialized tests are used to evaluate these components. The wet gluten test measures the amount of gluten protein in flour. The Amylograph and Rapid Visco Analyzer measure starch properties.

           This section is intended to provide some basic information on wheat and flour quality tests used by the wheat industry worldwide.

NAEGA | IGP @ K-State | Grain Science @K-State | Wheat Marketing Center | Northern Crops Institute | US Wheat Associates