In Vitro Fermentation of Arabinoxylan Oligosaccharides and Low Molecular Mass Arabinoxylans with Different Structural Properties from Wheat (Triticum aestivum L.) Bran and Psyllium (Plantago ovata Forsk) Seed Husk

Abstract

Ball milling was used for producing complex arabinoxylan oligosaccharides (AXOS) and low molecular mass arabinoxylans (AX) from wheat bran, pericarp-enriched wheat bran, and psyllium seed husk. The arabinose to xylose ratio of the samples produced varied between 0.14 and 0.92, and their average degree of polymerization (avDP) ranged between 42 and 300. Their fermentation for 48 h in an in vitro system using human colon suspensions was compared to enzymatically produced wheat bran AXOS with an arabinose to xylose ratio of 0.22 and 0.34 and an avDP of 4 and 40, respectively. Degrees of AXOS fermentation ranged from 28% to 50% and were lower for the higher arabinose to xylose ratio and/or higher avDP materials. Arabinose to xylose ratios of the unfermented fractions exceeded those of their fermented counterparts, indicating that molecules less substituted with arabinose were preferably fermented. Xylanase, arabinofuranosidase, and xylosidase activities increased with incubation time. Enzyme activities in the samples containing psyllium seed husk AX or psyllium seed husk AXOS were generally higher than those in the wheat bran AXOS preparations. Fermentation gave rise to unbranched short-chain fatty acids. Concentrations of acetic, propionic, and butyric acids increased to 1.9-2.6, 1.9-2.8, and 1.3-2.0 times their initial values, respectively, after 24 h incubation. Results show that the human intestinal microbiota can at least partially use complex AXOS and low molecular mass AX. The tested materials are thus interesting physiologically active carbohydrates.

LC-MS analysis reveals the presence of graminan- and neo-type fructans in wheat grains

“…Indeed, differences in fructan structure are most likely to cause differences in fermentation by the colon microbiota which may result in different health effects. Such correlation has been observed earlier for other types of dietary fiber (Pollet et al, 2011). In these cases, a higher degree of branching appeared to cause a slower fermentation by the gut microbiota.…”

The Ability of Bifidobacteria To Degrade Arabinoxylan Oligosaccharide Constituents and Derived Oligosaccharides Is Strain Dependent

“…Indeed, several ␣-arabinofuranosidases have been character- ized that are specific for Araf residues from monosubstituted Xylp, Araf residues from both mono-and disubstituted Xylp, and Araf residues from doubly substituted Xylp residues at position C-(O)-3 (38,39,41,42). Also, the degree of substitution (not determined in the present study) may be an important factor in the degradation of AXOS (less degradation with increasing A/X) and hence explain preferences for certain AXOS molecules (5,43). In addition, arabinose residues can be esterified with ferulic acid and could hinder the formation of ␣-arabinofuranosidase-substrate complexes (44).…”

Mutual Cross-Feeding Interactions between Bifidobacterium longum subsp. longum NCC2705 and Eubacterium rectale ATCC 33656 Explain the Bifidogenic and Butyrogenic Effects of Arabinoxylan Oligosaccharides

“…AX and their hydrolysis products, AXOS, are a promising class of prebiotics, as they have the potential to stimulate bifidobacteria, as ITF do, a so-called bifidogenic effect (12,(18)(19)(20)(21)(22)(23)(24). Also, like ITF, they seem to stimulate the production of butyrate and an increase in the relative abundance of Eubacterium spp., Roseburia spp., and F. prausnitzii, a so-called butyrogenic effect (12,18,19,21,(25)(26)(27)(28)(29).…”