In Vitro Bile Acid Binding Capacity of Wheat Bran Extruded at Five Specific Mechanical Energy Levels

Abstract

ABSTRACTThe in vitro binding of bile acids of extruded wheat bran (EWB) at five specific mechanical energy (SME) levels of 120 (EWB‐120), 177 (EWB‐177), 234 (EWB‐234), 291 (EWB‐291), and 358 (EWB‐358) Wh/kg on a dry weight basis, was determined using a mixture of bile acids secreted in human bile at a duodenal physiological pH 6.3. Experiments were conducted using six treatments and two blank incubations to test unextruded and extruded wheat bran samples on an equal dry matter (DM) basis. Relative to cholestyramine (bile acid binding, cholesterol‐lowering drug), in vitro bile acid binding ability of unextruded and extruded wheat bran treatments on an equal DM basis was 14–23%. The bile acid binding ability of the total dietary fiber (TDF) was 28–51% and insoluble dietary fiber (IDF) was 29–53%. Bile acid binding on DM, TDF, and IDF bases for EWB‐177 was significantly (P ≤ 0.05) higher, and EWB‐358 was significantly lower than UWB, EWB‐120, EWB‐234, and EWB‐291. Bile acid binding for EWB‐120 was significantly higher than that for UWB, EWB‐234, and EWB‐291. These results demonstrate the relative health promoting potential of EWB‐177 > EWB‐120 > UWB = WB‐234 = EWB‐291 >EWB‐358 as indicated by bile acid binding ability on DM, TDF, and IDF bases. The variability in bile acid binding of wheat bran treatments may be due to fragmenting of particles or macromolecules, creating new linkages in proteins, starches, and nonstarch polysaccharides, changes in physical and chemical characteristics, and binding sites.