Structural characterisation and determination of prebiotic activity of purified xylo-oligosaccharides obtained from Bengal gram husk (Cicer arietinum L.) and wheat bran (Triticum aestivum)

Water extractable polysaccharides (WEPs) were isolated from Bengal gram husk and wheat bran. These WEP were subjected to driselase enzyme hydrolysis to obtain oligosaccharide mixtures, which were purified successively on Biogel P-2 and high performance liquid chromatographies. The molecular weight and structural features of the purified oligosaccharides were deduced using ESI-MS and 1H NMR, respectively. The prebiotic properties of these purified oligosaccharides were studied by using Bifidobacterium adolescentis NDRI 236. Increase in dry cell mass (0.7–0.9 mg/ml) and decrease in pH (<5.8) due to production of short chain fatty acid (SCFA) indicated oligosaccharide fermentation. Acetate was the chief SCFA produced and its amount varied from 97.2% to 100%. The activities of xylanase (257–470 mU/ml), xylopyranosidase (53–60 mU/ml) and arabinofuranosidase (60–70 mU/ml) in the culture broth indicated the breakdown of xylo-oligosaccharides and their subsequent utilisation by the bacterium for its growth.