Feruloyl oligosaccharides stimulate the growth of Bifidobacterium bifidum

Insoluble dietary fiber from wheat bran contains some feruloyl groups linked to the arabinose residues in the cell wall arabinoxylan. Treatment of wheat bran insoluble dietary fiber with xylanase from Bacillus subtilis yielded feruloyl oligosacchairdes, which were purified with Amberlite XAD-2. Saponification of the feruloyl oligosaccharides released ferulic acid and arabinoxylan oligosaccharides which consist of arabinose and xylose. The effect of the feruloyl oligosacchairdes on the growth of Bifidobacterium bifidum F-35 was investigated in vitro. The B. bifidum produced acid when cultivated anaerobically in TPY broth with 0.5% feruloyl oligosacchairdes as the carbohydrate source. The biomass yield of the B. bifidum increased with increasing the concentration of feruloyl oligosaccharides in TPY broth. The maximum cell growth was increased by 50% in TPY broth supplemented with 0.1% feruloyl oligosaccharides compared to TPY broth. These results indicated that the growth of B. bifidum F-35 was promoted by the feruloyl oligosaccharides from wheat bran insoluble dietary fiber, and not suppressed by the ferulic acid moiety of them.