Anatomy of a whole grain

Anatomy of a whole grain

The grain is rich in ingredients that are largely essential to our body. It contains carbohydrates, proteins and fats – the three macronutrients. Whole grains also contain both micronutrients (vitamins and minerals) and phytochemicals. In today’s article you will find out which nutrients are contained in which part of the whole grain.


In general, a whole grain consists of

  • a germ (5 %)
  • an endosperm (approximately 80 %) and
  • the marginal layers, which include the fruit and seed shells and the aleurone layer (15%). [1]

The endosperm [2]

The endosperm forms the largest part of the grain in terms of quantity and weight. It consists of starch bodies between which there are adhesive proteins and which are delimited by fibre-rich cell dividing walls. The entire endosperm is surrounded by the so-called aleurone layer. This is composed of proteins and oils and is rich in B vitamins as well as vitamin E. The endosperm is an energy store that nourishes the germ – especially when it germinates.

The germ and the outer layers

The germ and outer layers are rich in vitamins and minerals, they contain fatty acids, including essential linoleic and alpha-linolenic acid, and high-quality protein.” [3] The outer layers protect the grain – but above all: the germ. This is also the reason why they are very rich in fibre.

We have summarized which vitamins can be found in the grain in another blog post for you. Have fun reading!



[1] Rittenau, N. (2019): Vegan-Klischee ade! Wissenschaftliche Antworten auf kritische Fragen zu veganer Ernährung. Mainz: Ventil Verlag UG & Co. KG,  S. 238

[2] Rittenau, N. (2019): S. 238; Münzing-Ruef, I. (2000): Kursbuch gesunde Ernährung. Die Küche als Apotheke der Natur. München: Wilhelm Heyne Verlag, S. 301; Koerber, K., Männle, T., Leitzmann, C. (2004): Vollwert-Ernährung : Konzeption einer zeitgemäßen und nachhaltigen Ernährung. Stuttgart: Haug, S. 244

[3] Koerber, K., Männle, T., Leitzmann, C. (2004): S. 244

Figure: (10.03.2020)