%0 Journal Article
%T Factors Involved in the In Vitro Fermentability of Short Carbohydrates in Static Faecal Batch Cultures
%A Eva Gietl
%A Wim Mengerink
%A Jaap de Slegte
%A Glenn Gibson
%A Robert Rastall
%A Ellen van den Heuvel
%J International Journal of Carbohydrate Chemistry
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/197809
%X In recent years, research has focused on the positive effects of prebiotics on intestinal health and gut microbiota. The relationship between their chemical structure and their fermentation pattern by human intestinal microbiota is still not well understood. The aim of this study was to improve understanding of this relationship and identify factors that may be used to design galactooligosaccharides that reach more distal regions than commercial prebiotics which mainly target the proximal colon. The following factors were investigated: monomer type, linkage, substitution, and degree of polymerisation. Total organic acid production from sugars by faecal bacteria was fitted to a model which allowed an estimate of the time when half of the maximal organic acid concentration was reached (T50) in static faecal batch cultures. The different factors can be grouped by their effectiveness at prolonging fermentation time as follows: substitution is most effective, with methylgalactose, -galactose-pentaacetate, D-fucose, and galactitol fermented more slowly than D-galactose. Monomers and linkage also influence fermentation time, with L rhamnose, arabinose, melezitose, and xylose being fermented significantly slower than D-glucose ( ), maltose, isomaltose, cellobiose, and gentiobiose showing that Glc 1-6Glc and Glc 1-4Glc were utilised slowest. Chain length had the smallest effect on fermentation time. 1. Introduction Epidemiological data [1¨C4] indicate that a diet high in dietary fibres from vegetables and grains is correlated to a reduced risk of certain diseases in humans, among them colon cancer, ulcerative colitis, and cardiovascular disease. Experimental evidence suggests that the short-chain fatty acids (SCFA), butyric, acetic, and propionic acids [3¨C5], play a role in this risk reduction. They are produced by the intestinal microbiota as a result of dietary fibre fermentation. Dietary fibres are plant materials, mostly storage carbohydrates or cell wall components, that cannot be digested in the human small intestine and reach the colon intact. They are available as substrates for the resident microbiota [6]. Some dietary fibres may also have prebiotic potential. Prebiotics are ˇ°non-digestible food ingredients that beneficially affect the host by selectively stimulating the growth and/or activity of one or a limited number of bacterial species already resident in the colon, and thus attempt to improve host healthˇ± [7]. Bacterial fermentation of carbohydrates in the colon results in the production of SCFA, mainly acetic, propionic, and butyric acid. Other
%U http://www.hindawi.com/journals/ijcc/2012/197809/