An antioxidant found in brown rice. Ferulic acid is found in the seeds of coffee, apple, artichoke, peanut, and orange, as well as in both seeds and cell walls of commelinid plants (such as rice, wheat, oats and pineapple). Often in the form of chlorogenic acid. In cereals, ferulic acid is localized in the bran the hard outer layer of grain. The highest known concentration of ferulic acid glucoside has been found in flax seed (4.1 ± 0.2 g/kg). It is also found in barley grain. In legumes, the white bean variety navy bean is the richest source of ferulic acid among the common bean (Phaseolus vulgaris) varieties. Although there are many sources of ferulic acid in nature, its bioavailability is limited based on the form in which it is present, with free ferulic acid having a poor water solubility hence poor bioavailability. In wheat grain, ferulic acid is found bound to cell wall polysaccharides, which has an effect on its release and absorption in the small intestine.