Metabolization of beta-(2,6)-linked fructose-oligosaccharides by differentbifidobacteria

Low-molecular-mass beta-(2,6)-linked fructose-oligosaccharides (beta-(2,6)- FOS) were examined as a new carbohydrate source for growth of bifidobacteri a. beta-(2,6)-FOS were prepared from microbial high-molecular-mass levan by acid hydrolysis and refined by cation-exchange chromatography. C-13-NMR sp ectroscopy confirmed the presence of predominantly beta-(2,6)-fructosyl lin kages in the oligosaccharides, More than 80% beta-(2,6)-FOS was recovered a fter in vitro incubation with amylolytic and proteolytic enzymes, implying resistance to degradation in the upper intestinal tract. Bifidobacterium ad olescentis, B. longum, B. breve, and B. pseudocatenulatum were studied in v itro for their ability to metabolize beta-(2,6)-FOS. Growth, decrease in pH , formation of short- chain fatty acids (lactate, acetate, formate) and deg radation of beta-(2,6)-FOS were markedly different among species. B. adoles centis showed the best growth, produced the highest amounts of organic acid s and metabolized both short- and long-chain beta-(2,6)-FOS. (C) 2000 Feder ation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.