Bran

Bran is the hard outer layer of grain and consists of combined aleurone and pericarp. Along with germ, it is an integral part of whole grains, and is often produced as a by-product of milling in the production of refined grains. When bran is removed from grains, they lose a portion of their nutritional value. Bran is present in and may be milled from any cereal grain, including rice, wheat, maize, oats, and millet.

Bran is particularly rich in dietary fiber, and contains significant quantitities of starch, protein, vitamins, and dietary minerals.

Bran is often used to enrich breads (notably muffins) 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.

Rice bran finds particularly many uses in Japan, where it is known as nuka (糠; ぬか). Besides using it for pickling, Japanese people also 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 sardine.

Rice bran is a by-product of the rice milling process, and it contains various antioxidants that impart beneficial effects on human health. It is well known that a major rice bran fraction contains 12%-13% oil and highly unsaponifiable components (4.3%). This fraction contains tocotrienol, 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 fibers (beta-glucan, pectin, and gum). In addition, it also contains 4-hydroxy-3-methoxycinnamic acid (ferulic acid), which may also be a component of the structure of non-lignified cell walls.

The high oil content of bran makes it subject to rancidification, one of the reasons that is often separated from the grain before storage or further processing. The bran itself can be heat-treated to increase its longevity.

Bran oil may be also extracted for use by itself for industrial purposes (such as in the paint industry), or as a cooking oil, such as rice bran oil.

In Romania, the fermented wheat bran is usually used when preparing sour soups, called borshch.

Health effects

Eating foods rich in bran became popular in the late 1970s and early 1980s, with many promotions of bran cereals and granola. In the late 1980s, there was the it became more popular, with more oat products in the market, claiming to lower blood cholesterol and fight heart disease. This populatity peaked in 1989, but was short-lived, as studies in the early 1990s showed that oat bran only modestly reduced cholesterol. However, in January 1997, the Food and Drug Administration decided (with some controversy) that food with a lot of oat bran or rolled oats can carry a label claiming it may reduce the risk of heart disease, when combined with a low-fat diet. As of 2005, this still appears on many oatmeal packages.

• Wheat bran (miller's bran) is very effective in treating constipation. Wheat bran is known to absorb large amounts of water and expand, which has led some to claim that bran helps lead to satiety by filling up the stomach with added volume.

Colorectal cancer might be prevented by dietary wheat bran. Indeed, many epidemiological studies pointed out a protective effect of fiber intake, and more than 15 preclinical studies show that wheat bran can reduce carcinogenesis in rats and mice. Thus, several randomized clinical trials were conducted in hundreds of volunteers to test the hypothesis that wheat bran supplements would reduce adenomatous polyp recurrence. Clinical and preclinical data are available on the Chemoprevention Database. Sadly, the main conclusion of these trials is that wheat bran does not prevent colorectal polyp recurrence: bran may thus not be an effective colon cancer preventing agent. There is strong evidence that rice bran may have a cancer preventive potential [1][2] [3].

• Oat bran, alone or as a part of oatmeal, has been shown to reduce the risk of coronary heart disease when part of an overall diet that is low in saturated fat and cholesterol, and the United States Food and Drug Administration now allows manufacturers to make specific health claims to that effect on food packaging.^[1]
• Rice bran fraction derived from Driselase treatment prevents high blood pressure, hyperlipidemia, and hyperglycemia.^[2] Driselase is a commercial plant cell wall-degrading enzyme mixture containing cellulase, xylanase, and laminarinase; however, it is esterase-free.

Bran for pets and companion animals

Bran is widely used as a major component in pet foods for rabbits and guinea pigs. Rice bran is sometimes fed to horses for its nutritional value, particularly as a plant-based fat supplement. Wheat bran is also sometimes fed to horses for its laxative qualities and nutritional value.

See also

• Alkylresorcinols
• Chaff
• Husk
• IP6
• Phytic acid

Outside Links

• Add Some Rice To Your Life--Advances in Rice-Based Products with Potential Benefits to Health (scientific paper), by Raxit J. Jariwalla, Ph.D.

References