Short-chain fatty acid content in the hindgut of rats fed various composite foods and commercial dietary fibre fractions from similar sources

The fermentability of indigestible carbohydrates and content of short-chain fatty acids along the hindgut of rats were investigated using plant materials of importance in the Swedish diet (instant potato powder, apples and oat flakes). Results with the composite food products were compared with commercial fibre fractions obtained from similar sources, ie potato fibre, apple pectin and beta-glucan-enriched oat fibre. The materials were incorporated into diets yielding a concentration of 60 or 70 g kg (1) indigestible carbohydrates. The fermentability of indigestible carbohydrates was high with all diets, between 79 and 90%. All substrates except the pure apple pectin generated intermediate to high proportions of butyric acid in the caecum (15-22 vs 8%). The potato products gave high concentrations of butyric acid in the distal colon. The potato powder, ie the diet with the highest content of resistant starch (22g kg(-1)), also gave the highest proportion of butyric acid in the distal colon (19%), which was higher than the proportion in the caecum with the same substrate (15%) (P < 0.005). The composite foods promoted a higher proportion of butyric acid in the distal colon as compared with the commercial fibre fractions (P < 0.05). (C) 2002 Society of Chemical Industry.