ARS | Publication request: Selective Fermentation of Gentiobiose Derived Oligosaccharides by Human Gut Bacteria and Influence of Molecular Weight

Submitted to: Federation of European Microbiological Societies Microbiology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 22, 2005
Publication Date: March 31, 2006
Citation: Luz Sanz, M., Cote, G.L., Gibson, G.R., Rastall, R.A. 2006. Selective fermentation of gentiobiose derived oligosaccharides by human gut bacteria and influence of molecular weight. Federation of European Microbiological Societies Microbiology Ecology. 56:383-388.

Interpretive Summary: New value-added markets are needed for such surplus agricultural commodities as sugar. Using a food-grade bacterium, complex carbohydrates were made from sugar and a bitter-tasting carbohydrate known as gentiobiose. Different sized molecules were separated and each was analyzed for its ability to support the growth of beneficial or detrimental bacteria. Certain sizes were better than others at supporting the growth of good intestinal bacteria. This provides information that will be useful in designing health-enhancing food and feed additives from agricultural commodities. Results will be of interest to researchers, sugar producers, and food industry processors.

Technical Abstract: Gentiooligosaccharides (GEOS) and alternansucrase (ASR) acceptor products with gentiobiose (AGOS) were fractionated by their degree of polymerization (DP) on a Bio Gel P2 column. Fractions were characterized by MALDI-TOF, and incubated with human fecal bacteria under anaerobic conditions at 37 deg C. Growth of predominant gut bacteria on the oligosaccharides was evaluated by fluorescence in situ hybridization and a prebiotic index (PI) calculated. Lower DP GEOS (DP 2-3) showed the highest selectivity (PI 4.89 and 3.40, respectively), whereas DP 4-5 AGOS generated the greatest values (PI 5.87). Production of short chain fatty acids was also determined during the time course of the reactions. The mixture of DP 6-10 AGOS generated highest levels of butyric acid but lowest lactic acid. Generally, for similar molecular weights, AGOS gave higher PI values than did GEOS.