Barley must have its fibrous outer hull removed before it can be eaten; pearl barley is taken a step further, polished to remove the nutritious bran layer.

In the process, vitamins and minerals in the bran layer are forced into the rice kernel, creating a more nutritious product but one that is inappropriate for many preparations.

Alkylresorcinols are present in high amounts in the bran layer (e.g. pericarp, testa and aleurone layers) of wheat and rye (0.1-0.3 % of dry weight).

Steel-cut oats are oat groats that have been chopped into smaller pieces and retain bits of the bran layer.

Many wheat varieties are reddish-brown due to phenolic compounds present in the bran layer which are transformed to pigments by browning enzymes.

Nowadays, the practice is to pass it through rollers without the outer bran layer, which is then added to the flour at a later stage.

Only the husks of the rice grains are removed during the milling process, retaining all the nutrients, vitamins and minerals intact in the bran layer and in the germ.

To produce white rice, the next layers underneath the husk (the bran layer and the germ) are removed, leaving mostly the starchy endosperm.

When the bran layer is removed to make white rice, the oil in the bran is also removed.

The bran layers of millets are good sources of B-complex vitamins.