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Bioavailability of new synthesised glucooligosaccharides in the intestinal tract of gnotobiotic rats
Author(s) -
Valette Pascale,
Pelenc Vincent,
Djouzi Zakia,
Andrieux Claude,
Paul François,
Monsan Pierre,
Szylit Odette
Publication year - 1993
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740620204
Subject(s) - butyric acid , fermentation , propionate , chemistry , lactic acid , digestion (alchemy) , isobutyric acid , caecum , food science , bioavailability , sucrose , mannitol , biochemistry , biology , bacteria , medicine , chromatography , genetics , bioinformatics
Using germ‐free rats and previously germ‐free rats inoculated with a complex human flora (heteroxenic rats), the digestibility of new glucooligosaccharides (GOS) and the effect of the digestive flora on their fermentation were studied. The GOS were synthesized using a glucosyltransferase reaction and were composed of a mixture of mono‐ to heptasaccharides (degree of polymerisation (DP) from 1 to 7), with α‐1,6 and α‐1,2 linkages. In germ‐free rats, two diets containing GOS (20 g kg −1 diet and 40 g kg −1 diet) were compared to a control diet containing sucrose. The extent of GOS digestion was about 20% and the major component, DP 5, was almost fully resistant to the action of endogenous enzymes. In heteroxenic rats, only GOS (20 g kg −1 diet) was compared to the control diet. Gaseous H 2 and CH 4 excretions measured in a respiratory chamber significantly increased by GOS fermentation (1.8 and 2.9 times, respectively, P < 0.001). As compared to the control group, there were no modifications of the pH, short‐chain fatty acids (SCFA), and lactic acid concentrations in the caecum of rats fed with the GOS diet, but there were changes of the SCFA profile, ie butyric, isobutyric and isovaleric acid proportions significantly decreased ( P < 0.01), whereas the caproic acid proportion increased ( P < 0.05). GOS appeared to be completely fermented. Changes in the gaseous excretion and in the SCFA profile suggest that the intake of a low amount of this new synthetised GOS led to some decrease in the proteolytic activity and in an enhancement of the glycolytic fermentation.