The degradation of guar gum by a faecal incubation system

Abstract

1. Homogenized and diluted faeces (SO g/l) from one human source were incubated with the complex plant polysaccharide, guar gum, to investigate the degradation of viscous polysaccharides by intestinal bacteria.2. Incubation of the faecal homogenate with guar gum produced a rapid decrease in viscosity and in pH, accompanied by the release of hydrogen.3. No changes in viscosity or pH were observed and there was no production of H, gas when guar gum was incubated with autoclaved faecal homogenate (20 min, 1.03 x lo5 Pa). 4.A bacteria-free filtrate of faeces was prepared by centrifuging the faecal homogenate (2400 g for 100 min) followed by filtration through a Seitz filter and then a millipore filter (size 0.45 pm). Incubating this with guar gum produced a slow decrease in viscosity, but no significant change in pH and no generation of H,.5 . Our results show that guar gum can be fermented by human colonic bacteria and suggest the possibility of predigestion by extracellular free enzymes.

Degradation of Guar Gum by Intestinal Bacteria

“…Some lactate was produced as well. This is in agreement with other studies (5,31). The data presented in Table 2 include SCFA and lactate produced from the medium components.…”

“…The fermentation of guar results in the formation of relatively large concentrations of butyrate (5,31). Formation of butyrate is considered to have a beneficial effect in the intestine (6).…”

“…Fermentation of guar results, as is the case with most undigestible carbohydrates, in the production of short chain fatty acids and gases. It has been noted in several studies that the fermentation of guar results in relatively large amounts of butyrate (5,31). However, none of the species known to ferment guar produces butyrate as a major fermentation end product.…”

In vitroStudy of Fiber Fermentability by Swine Fecal Microflora

“…pH has Carbohydrates reaching the large intestines may be broken down by the bacterial flora, through fermentation process to produce VFA and other gases such as hydrogen and carbon dioxide (Tomlin et al, 1986). Non-digestible oligosaccharides can be broken down through bacterial fermentation in the large intestine (Mussatto and Mancilha., 2007).…”

Physiological Functions of Partially Hydrolyzed Guar Gum

“…It has been found that guar gum passes through digestion by mammalian intestinal enzymes (α-glucosidase, sucrase and maltase) but it is readily broken down to low molecular weight galactomannan in the large intestine by extracellular and membrane-bound glycolytic enzymes of the intestinal microflora and then used by intestinal bacteria as a carbon source [7,8]. It has also been clear that partial hydrolysis by bacterial endo-β-mannanase represents the first step in the metabolism of ingested guar gum.…”