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United States Department of Agriculture

Agricultural Research Service

Title: Enrichment of Beta-Glucan from Oat Bran by Fine Grinding and Air Classification

Authors
item Wu, Ying Victor
item Doehlert, Douglas

Submitted to: Food Science and Technology International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2001
Publication Date: N/A

Interpretive Summary: Heart disease remains the number one cause of death in America, and Americans are ever more concerned with consuming a healthy diet. Oats contain soluble dietary fiber which lowers blood cholesterol in humans and, therefore, reduces the risk of heart disease. Oat bran contains more soluble dietary fiber than oats. An inexpensive method to concentrate soluble dietary fiber from oats or oat bran is needed. In this way one may not need to consume large amounts of oat products to reduce blood cholesterol. This report describes an inexpensive method to concentrate soluble dietary fiber from oat bran by fine grinding and separation in a stream of air. This work benefits American consumers by making soluble dietary fiber from oats more readily available in a concentrated form and benefits farmers by increasing demand for their product.

Technical Abstract: A strong positive correlation exists between blood cholesterol level and the risk of heart disease. Consumption of soluble dietary fiber can lower serum cholesterol in humans. Oats contain soluble dietary fiber, a major component of which is beta-glucan. Oat bran contains a higher percentage of beta-glucan than hull-less oats. Our objective was to enrich beta-glucan from oat bran by an inexpensive method. Hull-less oats were cleaned, steamed, and flaked. The oat flakes were partially defatted with hexane. The defatted flakes were ground and sieved to obtain defatted oat bran. The defatted oat bran was ground three times at 14,000 rpm in a pin mill, and the ground bran was separated into a fine and a coarse fraction in an air classifier with an initial set point of 15 microns. The coarse fraction was then successively separated into fine and coarse fractions with set points of 18, 24, and 30 microns. The defatted oat bran contained 11.1% of beta-glucan and 28.6% protein. The greater than 30 micron fraction, which accounted for 39.3% of defatted oat bran, contained 18.8% beta-glucan and 30.2% protein compared with 4.1% of beta-glucan and 29.1% protein for the less than 15 micron fraction. Some further increase in beta-glucan content was obtained by sieving the greater than 30 micron fraction into fractions of higher and lower beta- glucans. A 69% increase in beta-glucan content was obtained by this inexpensive air classification method. An 82% increase in beta-glucan content from the starting defatted oat bran was achieved by sieving the greater than 30 micron fraction. The enriched beta-glucan fraction was obtained in good yield and may have commercial potential as a food ingredient or for further processing.

Last Modified: 8/22/2014