title: Prebiotic evaluation of a novel galactooligosaccharide mixture produced by the enzymatic activity of Bifidobacterium bifidum NCIMB 41171, in healthy humans: a randomized, double-blind, crossover, placebo-controlled intervention study.
abstract: BACKGROUND
  Galactooligosaccharides are selectively fermented by the beneficial member of the colonic microflora contributing to the health of the host.
  
  
  OBJECTIVE
  We assessed the prebiotic potential of a novel galactooligosaccharide produced through the action of beta-galactosidases, originating from a probiotic Bifidobacterium bifidum strain, against a galactooligosaccharide produced through the action of an industrial beta-galactosidase and a placebo.
  
  
  METHODS
  Fifty-nine healthy human volunteers participated in this study. Initially, the effect of the matrix on the prebiotic properties of a commercially available galactooligosaccharide (7 g/d) was assessed during 7-d treatment periods with a 7-d washout period in between. During the second phase, 30 volunteers were assigned to a sequence of treatments (7 d) differing in the amount of the novel galactooligosaccharide (0, 3.6, or 7 g/d). Stools were recovered before and after each intervention, and bacteria numbers were determined by fluorescent in situ hybridization.
  
  
  RESULTS
  Addition of the novel galactooligosaccharide mixture significantly increased the bifidobacterial population ratio compared with the placebo (P < 0.05), whereas 7 g/d of the novel galactooligosaccharide significantly increased the bifidobacterial ratio compared with the commercial galactooligosaccharide (P < 0.05). Moreover, a significant relation (P < 0.001) between the bifidobacteria proportion and the novel galactooligosaccharide dose (0, 3.6, and 7 g/d) was observed. This relation was similar to the effect of the novel galactooligosaccharide on the prebiotic index of each dose.
  
  
  CONCLUSIONS
  This study showed that galactooligosaccharide mixtures produced with different beta-galactosidases show different prebiotic properties and that, by using enzymes originating from bifidobacterial species, an increase in the bifidogenic properties of the prebiotic product is achievable.
authors.affiliation: School of Food Biosciences, The University of Reading, Reading, United Kingdom, and the Institute of Food Research, Colney, Norwich, United Kingdom.
authors.forename: Flore
authors.initials: F
authors.lastname: Depeint
authors.forename: George
authors.initials: G
authors.lastname: Tzortzis
authors.forename: Jelena
authors.initials: J
authors.lastname: Vulevic
authors.forename: Kerry
authors.initials: K
authors.lastname: I'anson
authors.forename: Glenn R
authors.initials: GR
authors.lastname: Gibson
mesh_terms: D000328:Adult; D001644:Bifidobacterium / Q000201:enzymology*; D003106:Colon / Q000378:metabolism / Q000382:microbiology; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005243:Feces / Q000382:microbiology; D005260:Female; D005285:Fermentation; D005690:Galactose / Q000096:biosynthesis / Q000378:metabolism*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D008297:Male; D009844:Oligosaccharides / Q000096:biosynthesis / Q000378:metabolism*; D019936:Probiotics; D001616:beta-Galactosidase / Q000378:metabolism*
chemical_list: D009844:Oligosaccharides; D001616:beta-Galactosidase; D005690:Galactose