RICE BRAN

Rice bran is one of the main byproducts in the process of the rice milling. It is the outer brown layer of brown rice and is separated during the milling process. All over the world, > 63 million tons of rice bran is produced each year (Webber et al., 2014). Rice bran contains lipid (rice bran contains 15–20% oil), and high activities of lipases and lipoxygenases result in easy rancidity of the lipid due to lack of economic stabilization methods (Lakkakula et al., 2004).

Therefore rice bran is mainly used as livestock feed or boiler fuel, and only a small amount is applied to extraction and preparation rice bran oil (Webber et al., 2014). To improve utilization of rice bran, development of feasible stabilization methods and the value-added processes of the nutrients and active compositions are necessary. Oil, proteins, and carbohydrates are the main nutrients in rice bran. There are also plenty of other nutrients and active compositions, such as nonstarch polysaccharides, phenolic acids, flavonoids, tocopherols, tocotrienols, c-oryzanol, and phytic acid.

Most of these compounds have antioxidant and anticancer activities (Goufo and Trindade, 2014, Henderson et al., 2012). Defatted rice bran (DRB), also called rice bran meal, is the main byproduct in the extraction process of the rice bran oil from full fat rice bran (FRB) (Kaur et al., 2012). Most of the water-soluble chemicals are in the DRB, including most carbohydrates, proteins, and phytic acid. In this chapter, areas of research related to the nutrition and active compositions in the DRB are highlighted.

The outline of this chapter is as follows: nutritional ingredients in the FRB and DRB; the starch and its application in the DRB; structures and applications of the nonstarch polysaccharides in the DRB; brief introduction to the rice bran protein; other active phytochemicals in the DRB; and the development prospect of the DRB.