Fermentation patterns and short chain fatty acid profiles of wheat dextrin and other functional fibres

Gut fermentation of carbohydrates that escape digestion and absorption in the upper gastrointestinal tract has benefits for colonic health. These benefits include increase in stool weight, speeded intestinal transit, short chain fatty acid production, alterations in microflora, and decreased colonic pH. Wheat dextrin is a glucose polysaccharide (resistant starch) with a narrow molecular weight and a proven safety profile. Wheat dextrin, a fermentable soluble fibre, is well tolerated in human subjects and acts as a prebiotic supplement with beneficial effects on the gut ecosystem. We assessed the fermentation of wheat dextrin and other fibres in an in vitro system in a series of experiments with and without the probiotic Lactobacillus reuteri. Short chain fatty acid (SCFA) production with wheat dextrin was largely unaffected by addition of probiotic. We also examined SCFA profiles, fermentation patterns, and gas production in an in vitro study comparing wheat dextrin, psyllium, and inulin. All fibres decreased pH because of SCFA production, while inulin produced more rapid fermentation and gas production than wheat dextrin and psyllium. Inulin was the only fibre with measurable gas production at 8 hours. Total SCFA production was similar for all fibres; wheat dextrin had higher propionate than inulin. The highest molar percentage of butyrate was found with inulin. Differences in fermentation rate, gas production, and SCFA production observed for wheat dextrin vs. other fibres may have therapeutic implications in digestion and absorption that warrant further investigation.