Brans

Cereal grain is composed of three main parts: starchy endosperm, bran and germ. Grain milling aims to separate these three parts, resulting in pure endosperm flour and different side stream products like bran. Cereal bran comprises 3-30 % of the dry weight of cereal grain, depending on the type of cereal. Figure 1 presents bran fractions of oat, maize and wheat.

Figure 1. Bran fractions of oat, maize and wheat

Figure 2 shows the anatomical parts of the wheat grain. Bran forms a protective layer around the grain, and the bran is further composed of multiple layers including pericarp, testa, hyaline and aleurone layer. 

Figure 2. Histological parts of wheat grain (Picture from Hemery et al. 2007, original picture from Surget and Barron 2005)

Cereal bran is a good source of dietary fiber, protein, minerals, E and B-vitamins and different phenolic compounds. Table 1 shows the amounts of some of the nutritional components of wheat, oat and maize bran.

Table 1. The amounts of some nutritional components of wheat, oat and maize bran (Source a: THL 2021, source b: USDA 2021)

References

  • [THL] Nutrition Unit of the National Institute for Health and Welfare: Fineli, National Food Composition Database in Finland. [Date cited: 15.9.2021]. Available: https://fineli.fi/fineli/en/index
  • [USDA] U.S. Department of Agriculture: FoodData Central. [Date cited: 17.9.2021]. Available: https://fdc.nal.usda.gov/
  • Surget A, Barron C. Histologie du grain de blé. Industrie des Céréales 2005, 145: 3–7. In: Hemery Y, Xavier R, Lullien-Pellerin V, Barron C, Abecassis J. Dry process to Develop wheat fractions and products with enhanced nutritional quality. Journal of Cereal Science 2007, 46: 327–347.