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United States Department of Agriculture

Agricultural Research Service

Title: Co-Products from Rice Processing

Authors
item Guraya, Harmeet
item James Jr, Charles
item Champagne, Elaine

Submitted to: International Starch Technology Conference
Publication Type: Proceedings
Publication Acceptance Date: April 11, 2003
Publication Date: June 4, 2003
Citation: Guraya, H.S., James Jr, C., Champagne, E.T. 2003. Co-products from rice processing. International Starch Technology Conference. 74-91.

Interpretive Summary: An overview of the latest and important developments in rice processing are presented, including some work at USDA. The first unit operation in milling of rice removes the hull to produce brown rice. Until now, limited commercial uses of hulls include steam generation, filtration media and poultry bedding material. New uses being developed include using modified rice hulls or rice hull extract for cleaning water as ingredient for electronics industry and as food films. Brown rice obtained after de-hulling is one of the most nutritious forms of rice but due to long cooking times, it is not popular. A new method for instantizing brown rice by flourblasting was developed at USDA. A commercial prototype was developed and several licenses have been issued. In the second unit operation, the brown rice is usually milled to produce white rice and rice bran. Approximately 60 million metric tons of rice bran is produced worldwide. It is mostly being used in low value application as animal feed and for oil extraction. Due to the presence of a large number and amount of biologically active components, a variety of rice bran extracts are being sold for food and non-foods uses. The processes for making extracts and the uses are discussed. In the third unit operation, milled rice is further processed to yield pure rice starch and is primarily being imported from Europe. Recently, a novel process for making rice starch and protein was developed at USDA.

Technical Abstract: The first unit operation in milling of rice removes the hull to produce brown rice. The hull is the least nutritious part of rice containing about 20% silica. Until now, limited commercial uses of hulls include steam generation, filtration media, and poultry bedding material. New uses being developed include; using rice hulls as anion exchange resins, flexible sodium silicate films, and silica xerogels. Brown rice obtained after de-hulling is one of the most nutritious forms of rice, but due to long cooking times, it is not popular. A new method for instantizing brown rice by flourblasting was developed in our lab. A commercial prototype was developed and several licenses have been issued. In the second unit operation, the brown rice is usually milled to produce white rice and rice bran. Approximately 60 million metric tons of rice bran is produced worldwide. It is mostly being used in low value application as animal feed and for oil extraction. Due to the presence of a large number and amount of biologically active components, a variety of rice bran extracts are being sold for food and non-foods uses. The processes for making extracts and its uses will be discussed. Protein from rice bran is nutritious and hypoallergenic. In the third unit operation, milled rice is further processed to yield pure rice starch. Rice starch (<0.5% protein) is primarily being imported from Europe. In a recent development in our laboratory, starch-protein agglomerates of rice are physically disrupted in the presence of water by use of a high pressure homogenizer called microfluidizer® followed by density base separation. This process is currently being scaled-up for commercialization by Sage V Foods from California. Laboratory methods for washing starch using various density gradient systems and their effect on starch purity were studied.

Last Modified: 9/29/2014
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