Abstract #567

# 567
Lactose and lactose derivatives: More than prebiotics?
Michael Gänzle*1, 1University of Alberta, Edmonton, AB, Canada.

Commercially available lactose derivatives include lactulose (β-4’galactosylfructose), lactosucrose (β-4’galactosylsucrose), and galacto-oligosaccharides. 3-, 4-, and 6-Galactobiose, allolactose, and 6-, 3-, and 4-galactosyllactose are the major components of commercial galacto-oligosaccharide preparations. Commercial processes for lactose conversion generally employ enzymatic transglycosylation with fructose, sucrose, and lactose, respectively, as galactosyl acceptors. Because human β-galactosidase is specific for lactose, enzymatic transgalactosylation coverts lactose, a disaccharide that is indigestible in about 75% of human adults, to oligosaccharides that are indigestible in all human infants and adults. Galacto-oligosaccharides and other lactose derivatives are fermented by colonic microbiota. Galacto-oligosaccharides increase the abundance of bifidobacteria in intestinal microbiota and are thus recognized as prebiotic compounds. However, the increase of bifidobacteria in human microbiota depends on the individual composition of the microbiota and is observed in most but not in all individuals. Health benefits of consumption of galacto-oligosaccharides are predominantly derived from intestinal fermentation to short chain fatty acids and may be independent of the stimulation of specific taxa in the human gut. In analogy to lactose intolerance, over-consumption of galacto-oligosaccharides results in intestinal discomfort and osmotic diarrhea. In addition to their prebiotic activity, galacto-oligosaccharides have been shown to prevent the adhesion of enteric pathogens to mucosal surfaces. Their activity is likely mediated by specific interaction with bacterial glycan recognition proteins that are involved in early steps of pathogenesis. The prevention of pathogen adhesion is a complementary mechanism of galacto-oligosaccharides to specifically benefit host health. The concept of preventing pathogen adhesion was validated in vivo with swine models; anti-adhesive glycans may be used as functional food ingredient but also in animal production to reduce the use of antimicrobial growth promoters.

Key Words: lactose β-galactosidase galacto-oligosaccharide, pathogen adhesion

Speaker Bio
Education:
1992 Master of Science, Oregon State University, Corvallis, USA;
1994 Diplom Lebensmittelingenieur, Universität Hohenheim, Stuttgart, Germany
1998 Doctor rerum naturae, Universität Hohenheim, Stuttgart, Germany
Professional Experience
until 2/2005 Post-doctoral fellow and Assistant Professor at the Technische Universität München,
Lehrstuhl Technische Mikrobiologie
since 3/2005 Assistant Professor, University of Alberta (Full Professor since 7/2011)
since 3/2013 Lecturing Professor at the Hubei University of Technology, Wuhan, China.

Research Experience and Publications:
Research projects focus on the functional characterisation of lactic acid bacteria for use as starter cultures, protective cultures, or probiotics in food with a focus on cereal-associated lactic acid bacteria; production of oligosaccharides from sucrose or lactose by lactic acid bacteria and biological activities of oligosaccharides; novel, non-thermal preservation methods with a focus on high pressure processing and biopreservation; and intestinal microbial ecology with focus on the use of prebiotic carbohydrates and dietary fibre to improve host health. Research results are documented in over 159 peer-reviewed publications (accepted or printed) which were cited more than 3600 times (h-index of 36), 36 non-refereed original article or book chapters, 5 patents or patent applications, 59 invited oral presentations at national and international symposia, academic institutions, or industry workshops.