Abstract: Two dietary fibers(DF) — DF1 and DF2 were extracted from corn bran using different α-amylases and proteinases, of which the content of total dietary fiber (TDF) were 88.0% and 82.8%. Then the effects of cellulase and xylanase on the composition and function properties of DF2 were studied. The content of soluble dietary fiber (SDF) of the fiber DF3 made from DF2 by cellulase hydrolysis increased to 402%. The swelling capacity (SW) and oil-binding capacity(OBC)of DF3 increased significantly(p<0.05). But there was no promotion of the binding of bile acids in vitro by DF3 through the determination of HPLC. The content of insoluble dietary fiber (IDF) of the fiber DF4 made from DF2 though xylanase hydrolysis increased to 112% of DF2. The water-holding capacity (WHC), SW and OBC of DF4 all increased significantly (p<0.05). The average binding of Sodium cholate (C), Sodium chenodeoxycholate (CDC), Sodium deoxycholate (DC) and Sodium taurocholate (TC) in vitro by DF4 was 1.66 fold of DF2, especially the binding of hydrophobic bile acids of DC and CDC increased by 316% and 478%. The functional properties of binding of bile acids, SW, WHC and OBC of the dietary fibers made by different methods were quite different as well as their composition. The combination of α-amylase, proteinase and xylanase improved these functional properties significantly.

Key words: bio-preparation, corn bran, dietary fiber, composition, functional property