In cereals, ferulic acid is localized in the bran the hard outer layer of grain. In wheat, phenolic compounds are mainly found in the form of insoluble bound ferulic acid and be relevant to resistance to wheat fungal diseases.[3] The highest known concentration of ferulic acid glucoside has been found in flax seed (4.1 ± 0.2 g/kg).[4] It is also found in barley grain.[