Dietary fiber in cereal grains

Cereals are the major source of fiber in human diets, providing about half of the total intake. It has a number of health benefits and increased fiber consumption is a major priority for improving consumer health. Fiber is a complex fraction, comprising mainly cell wall polysaccharides (cellulose, arabinoxylan, and β-glucan) with associated lignin and fructans (fructo-oligosaccharides). It is concentrated in the outer layers of cereal grains (notably the pericarp and aleurone layer) where it may account for up to half of the dry weight but low (often less than 5% dry weight) in the starchy endosperm. It is therefore severely depleted in processed grain fractions corresponding to the starchy endosperm such as white wheat flour, polished rice, decorticated sorghum and millets. In addition to health benefits, fiber also affects grain processing properties, particularly due to its high water-binding.