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United States Department of Agriculture

Agricultural Research Service

Title: In Vitro Binding of Bile Acids by Rice Bran, Oat Bran, Barley and B-Glucan Enriched Barley

Authors
item Kahlon, Talwinder
item Woodruff, Carol

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 19, 2002
Publication Date: May 10, 2003
Citation: Kahlon, T.S., Woodruff, C.L. 2003. In vitro binding of bile acids by rice bran, oat bran, barley and b-glucan enriched barley. Cereal Chemistry. Vol. 80, p. 260-263.

Interpretive Summary: The healthful or cholesterol-lowering properties of cereal brans could be predicted by evaluating their in vitro bile acid binding as it has potential to lower plasma and liver cholesterol and excrete toxic metabolites. Observed bile acid binding was rice bran, 68%; oat bran 26%; dehullled barley, 41% and B-glucan enriched barley, 49%; compared with cholestyramine on a protein basis. Bile acid binding by rice bran may account to a great extent for its cholesterol-lowering properties while bile acid binding by oat bran suggests that the primary mechanism of cholesterol-lowering by oat bran is not due to the bile acid binding by its soluble fiber. Bile acid binding did not appear to be proportional to the soluble fiber content of the cereal brans tested. High bile acid binding values, based on an equal protein basis of all four cereals tested, suggest that cereal protein composition, structure, metabolites and/or their interaction with active binding sites may determine bile acid binding potential.

Technical Abstract: The in vitro bile acid binding by rice bran, oat bran, dehulled barley and B-glucan enriched barley was determined using a mixture of bile acids normally secreted in human bile at a duodenal physiological pH of 6.3. Six treatments and two blank incubations were conducted testing substrates on an equal protein basis. The relative in vitro bile acid binding of the cereal brans on an equal total dietary fiber (TDF) basis considering cholestyramine as 100% bound, was rice bran, 45%; oat bran, 23%; dehulled barley, 33%; and B-glucan enriched barley, 20%. Bile acid bindings on equal protein basis for the respective cereals were 68, 26, 41 and 49%. Bile acid binding by rice bran may account to a great extent for its cholesterol-lowering properties, while bile acid binding by oat bran suggests that the primary mechanism of cholesterol-lowering by oat bran is not due to the bile acid binding by its soluble fiber. Bile acid binding was not proportional to the soluble fiber content of the cereal brans tested. High bile acid binding values based on an equal protein basis of all four cereals tested suggest that cereal protein composition, structure, metabolites and/or their interaction with active binding sites may determine bile acid binding potential.

Last Modified: 11/23/2014
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