Bran
Bran, also known as miller's bran, is the component of a cereal grain consisting of the hard layersthe combined aleurone and pericarpsurrounding the endosperm. Corn bran also includes the pedicel. Along with the germ, it is an integral part of whole grains, and is often produced as a byproduct of milling in the production of refined grains. Bran is highly nutritious, but is difficult to digest due to its high fiber content; its high fat content also reduces its shelf life as the oils/fats are prone to becoming rancid. As such, it is typically removed from whole grain during the refining processe.g. in processing wheat grain into white flour, or refining brown rice into white rice.
Bran is present in cereal grain, including rice, corn, wheat, oats, barley, rye, and millet. Bran is not the same as chaff, which is a coarser, scaly material surrounding the grain and is indigestible by humans.
Composition
Bran is particularly rich in dietary fiber and essential fatty acids, and contains significant quantities of starch, protein, vitamins, and dietary minerals. It is also a source of phytic acid, an antinutrient that prevents nutrient absorption.The high oil content of bran makes it subject to rancidification, one of the reasons that it is often separated from the grain before storage or further processing. Bran is often heat-treated to increase its shelf life.
| Nutrients | Wheat | Rye | Oat | Rice | Barley |
| Carbohydrates | 45–50 | 50–70 | 16–34 | 18–23 | 70–80 |
| Starch | 13–18 | 12–15 | 18–45 | 18–30 | 8–11 |
| Proteins | 15–18 | 8–9 | 13–20 | 15–18 | 11–15 |
| Fats | 4–5 | 4–5 | 6–11 | 18–23 | 1–2 |
Rice bran
Rice bran is a byproduct of the rice-milling process, and it contains various antioxidants. A major rice bran fraction contains 12%–13% oil and highly unsaponifiable components. This fraction contains tocotrienols, gamma-oryzanol, and beta-sitosterol; all these constituents may contribute to the lowering of the plasma levels of the various parameters of the lipid profile. Rice bran also contains a high level of dietary fiber. It also contains ferulic acid, which is also a component of the structure of nonlignified cell walls. Some research suggests, though, inorganic arsenic is present at some level in rice bran. One study found the levels to be 20% higher than in contaminated drinking water.Uses
Bran is often used to enrich breads and breakfast cereals, especially for the benefit of those wishing to increase their intake of dietary fiber. Bran may also be used for pickling as in the tsukemono of Japan, as well as in the production of East Asian black vinegars.Rice bran in particular finds many uses in Japan, where it is known as nuka. Besides using it for pickling, Japanese people add it to the water when boiling bamboo shoots, and use it for dish washing. In Kitakyushu City, it is called jinda and used for stewing fish, such as sardines.
Wheat bran is useful as feed for poultry and other livestock, as part of a balanced ration with other inputs. Wheatings, a milling byproduct comprising mostly bran with some pieces of endosperm also left over, are included in this category.
Bran oil may be also extracted for use by itself for industrial purposes, or as a cooking oil, such as rice bran oil.
Bran was found to be the most successful slug deterrent by BBC's TV programme Gardeners' World. It is a common substrate and food source used for feeder insects, such as mealworms and waxworms. Wheat bran has also been used for tanning leather since at least the 16th century.