Background and aimsPrebiotics such as Arabinoxylooligosaccharides (AXOS) are non-digestible, fermentable food ingredients stimulating growth/activity of colonic bacteria with enhanced carbohydrates fermentation (CF) in humans. The migrating motor complex (MMC) of the gastrointestinal tract has been recently identified as an important hunger signal, but no data are available yet on the role of acute CF on MMC activity and related hunger ratings. Thus, we aimed to study the effect of acute AXOS CF on MMC and hunger in humans. MethodsA total of 13 healthy volunteers were randomized in a single-blind crossover placebo-controlled study where 9.4g of AXOS or 10g of maltodextrin and 1g of unlabelled lactose ureide (LU) were given 12hours prior to the study and, in the next morning, together with a pancake containing 500mg of C-13-LU. In 10 hours after the meal, (CO2)-C-13 and hydrogen excretion were determined every 15minutes while hunger/appetite ratings every 2minutes through a VAS questionnaire. Five hours after the meal, antroduodenal motility was measured using HRM. Key ResultsAXOS significantly increased CF (15881 vs 840 +/- 464 H2 ppm*minute, placebo vs AXOS, P<.05) without affecting the orocecal transit time (OCTT). AXOS had no significant effect on the occurrence, origin, and duration of phase III and on the total number, origin, and duration of phases I and II. Hunger and appetite scores prior and after phase III were not affected by AXOS. ConclusionsAXOS acutely increases colonic fermentation, but this neither affects OCTT, activity of the MMC, nor interdigestive hunger scores in man.

Background Intestinal microbiota regulates gastrointestinal sensory-motor function. Prebiotics such as arabinoxylan-oligosaccharide (AXOS) are non-digestible, fermentable food ingredients beneficially affecting intestinal microbiota, colon activity, and improving human health. We wanted to investigate whether acute AXOS or maltodextrin (placebo) administration may alter gastric sensitivity (GS), accommodation (GA), nutrient tolerance (NT) in man. Methods Thirteen HV (6 M, 32.2 +/- 1.8 years; BMI 22.3 +/- 0.2) underwent two 48 h treatment periods with oral 4 x 9.4 g AXOS or 4 9 10 g maltodextrin (at least 1 week wash-out) for gastric barostat assessment of GS, gastric compliance (GC), GA to a liquid test meal, on day 1, and NT drink test, on day 2. Oro-cecal transit-time (OCTT), colonic fermentation (CF) were assessed simultaneously with 13 C-lactose ureide, H-2 breath tests. Key Results Arabinoxylanoligosaccharide significantly increased CF on day 1 and 2 (565 +/- 272 vs 100 +/- 24, 365 +/- 66 vs 281 +/- 25 H2 ppm/min, AXOS vs maltodextrin, both p < 0.05), not the OCTT. AXOS did not alter GC, sensitivity before and after the meal. Gastric accommodation was not significantly influenced by AXOS (volume increment: 171 +/- 33 vs 130 +/- 28 mL, AXOS vs maltodextrin, p = NS). On day 1, AXOS fermentation was associated with significantly higher postprandial bloating scores (960 +/- 235 vs 396 +/- 138 mm*min, AXOS vs maltodextrin, p < 0.05). On day 2, AXOS did not affect maximal NT (946 +/- 102 vs 894 +/- 97 mL, AXOS vs maltodextrin, p = NS), increased the bloating score (1236 +/- 339 vs 675 +/- 197 mm*min, AXOS vs maltodextrin, p < 0.05). Conclusions & Inferences Acute AXOS administration, associated with increased CF, does not affect GA, is not associated with increased meal-induced satiety or perception scores.

This article reviews the current knowledge of the health effects of dietary fiber and prebiotics and establishes the position of prebiotics within the broader context of dietary fiber. Although the positive health effects of specific fibers on defecation, reduction of postprandial glycemic response, and maintenance of normal blood cholesterol levels are generally accepted, other presumed health benefits of dietary fibers are still debated. There is evidence that specific dietary fibers improve the integrity of the epithelial layer of the intestines, increase the resistance against pathogenic colonization, reduce the risk of developing colorectal cancer, increase mineral absorption, and have a positive impact on the immune system, but these effects are neither generally acknowledged nor completely understood. Many of the latter effects are thought to be particularly elicited by prebiotics. Although the prebiotic concept evolved significantly during the past two decades, the line between prebiotics and nonprebiotic dietary fiber remains vague. Nevertheless, scientific evidence demonstrating the health-promoting potential of prebiotics continues to accumulate and suggests that prebiotic fibers have their rightful place in a healthy diet.

Un premier aspect de la presente invention concerne un procede de preparation d'un produit alimentaire a boire comprenant un composant alimentaire liquide et un composant alimentaire solide particulaire, ledit procede comprenant les etapes consistant a mettre en suspension ledit composant alimentaire solide particulaire dans ledit composant alimentaire liquide dans un rapport massique humide entre 1/20 et 1/3 (p/p). Avant sa suspension dans le composant alimentaire liquide, ledit composant alimentaire solide particulaire presente generalement une taille de particules D 50 comprise entre 2,0 mm et 10,0 mm, une dimension particulaire D 90 inferieure a 12,0 mm et une D100 taille de particule inferieure a 14,0 mm. En outre, il est preferable que, avant la suspension du composant alimentaire solide particulaire dans le composant alimentaire liquide, ledit composant alimentaire liquide presente une contrainte d'ecoulement a 6 °C comprise entre 0,30 Pa et 20 Pa et une viscosite a 6 °C et a une vitesse de cisaillement de 10 s -1 comprise entre 100 mPa.s et 1500 mPa.s, ladite contrainte d'ecoulement et la viscosite sont mesurees entre 2 et 5 minutes des le melange turbulent pendant 1 minute dudit composant alimentaire liquide. De plus, il est preferable que, avant la suspension du composant alimentaire solide particulaire dans le composant alimentaire liquide, le rapport de la densite totale des particules du composant alimentaire solide particulaire a 22 °C au-dessus de la densite du composant alimentaire liquide a 22 °C se situe entre 0,75 et 1,15. Dans un second objet, la presente invention concerne un ensemble permettant de preparer un produit alimentaire a boire pouvant etre obtenu selon le procede de la presente invention, cet ensemble comprenant un composant alimentaire solide particulaire avec une taille de particules D 50 comprise entre 2,0 mm et 10,0 mm, une dimension particulaire D 90 inferieure a 12,0 mm et une taille de particule D 100 inferieure a 14,0 mm, et un composant alimentaire liquide, avec une contrainte d'ecoulement a 6 °C comprise entre 0,30 Pa et 20 Pa et une viscosite a 6 °C et a une vitesse de cisaillement de 10 s -1 comprise entre 100 mPa.s et 1500 mPa.s, ladite contrainte d'ecoulement et la viscosite etant mesurees entre 2 et 5 minutes des le melange turbulent pendant 1 minute dudit composant alimentaire liquide, le rapport de la densite totale des particules du composant alimentaire solide particulaire a 22 °C au-dessus de la densite du composant alimentaire liquide a 22 °C se situant entre 0,75 et 1,15, et ledit composant alimentaire solide particulaire et le composant alimentaire liquide etant conditionnes separement.

SCOPE In vitro and animal studies have shown differential colonic fermentation of structurally different prebiotics. We evaluated the impact of two structurally different prebiotics (wheat bran extract (WBE, containing arabinoxylan-oligosaccharides) and oligofructose) on colonic fermentation and markers of bowel health in healthy volunteers. METHODS AND RESULTS Nineteen healthy subjects completed a double-blind, cross-over randomized controlled trial. Interventions with WBE, oligofructose or placebo for 2 wk (week 1: 15 g/day; week 2: 30 g/day) were separated by 2-wk wash-out periods. At the end of each study period, colonic fermentation was characterized through a metabolomics approach. Fecal water genotoxicity and cytotoxicity were determined using the comet and WST-1 assay, respectively, as parameters of gut health. Cluster analysis revealed differences in effects of WBE and oligofructose on colonic fermentation. WBE, but not oligofructose, reduced fecal p-cresol (p = 0.009) and isovaleric acid concentrations (p = 0.022), markers of protein fermentation. Fecal water cytotoxicity was significantly lower after intake of WBE (p = 0.015). Both WBE- and oligofructose-intake tended to reduce fecal water genotoxicity compared to placebo (WBE: p = 0.060; oligofructose: p = 0.057). Changes in fermentation were not related to changes in fecal water toxicity. CONCLUSION Structurally different prebiotics affect colonic fermentation and gut health in a different way.

Wheat bran extract (WBE), containing arabinoxylan-oligosaccharides that are potential prebiotic substrates, has been shown to modify bacterial colonic fermentation in human subjects and to beneficially affect the development of colorectal cancer (CRC) in rats. However, it is unclear whether these changes in fermentation are able to reduce the risk of developing CRC in humans. The aim of the present study was to evaluate the effects of WBE on the markers of CRC risk in healthy volunteers, and to correlate these effects with colonic fermentation. A total of twenty healthy subjects were enrolled in a double-blind, cross-over, randomised, controlled trial in which the subjects ingested WBE (10 g/d) or placebo (maltodextrin, 10 g/d) for 3 weeks, separated by a 3-week washout period. At the end of each study period, colonic handling of NH3 was evaluated using the biomarker lactose[15N, 15N']ureide, colonic fermentation was characterised through a metabolomics approach, and the predominant microbial composition was analysed using denaturing gradient gel electrophoresis. As markers of CRC risk, faecal water genotoxicity was determined using the comet assay and faecal water cytotoxicity using a colorimetric cell viability assay. Intake of WBE induced a shift from urinary to faecal 15N excretion, indicating a stimulation of colonic bacterial activity and/or growth. Microbial analysis revealed a selective stimulation of Bifidobacterium adolescentis. In addition, WBE altered the colonic fermentation pattern and significantly reduced colonic protein fermentation compared with the run-in period. However, faecal water cytotoxicity and genotoxicity were not affected. Although intake of WBE clearly affected colonic fermentation and changed the composition of the microbiota, these changes were not associated with the changes in the markers of CRC risk.

Objectives:We assessed whether wheat bran extract (WBE) containing arabinoxylan-oligosaccharides (AXOS) elicited a prebiotic effect and modulated gastrointestinal (GI) parameters in healthy preadolescent children upon consumption in a beverage.Methods:This double-blind randomized placebo-controlled crossover trial evaluated the effects of consuming WBE at 0 (control) or 5.0 g/day for 3 weeks in 29 healthy children (8-12 years). Fecal levels of microbiota, short-chain fatty acids, branched-chain fatty acids, ammonia, moisture, and fecal pH were assessed at the end of each treatment and at the end of a 1-week run-in (RI) period. In addition, the subjects completed questionnaires scoring distress severity of 3 surveyed GI symptoms. Finally, subjects recorded defecation frequency and stool consistency.Results:Nominal fecal bifidobacteria levels tended to increase after 5 g/day WBE consumption (P = 0.069), whereas bifidobacteria expressed as percentage of total fecal microbiota was significantly higher upon 5 g/day WBE intake (P = 0.002). Additionally, 5 g/day WBE intake induced a significant decrease in fecal content of isobutyric acid and isovaleric acid (P < 0.01), markers of protein fermentation. WBE intake did not cause a change in distress severity of the 3 surveyed GI symptoms (flatulence, abdominal pain/cramps, and urge to vomit) (P > 0.1).Conclusions:WBE is well tolerated at doses up to 5 g/day in healthy preadolescent children. In addition, the intake of 5 g/day exerts beneficial effects on gut parameters, in particular an increase in fecal bifidobacteria levels relative to total fecal microbiota, and reduction of colonic protein fermentation.

Wheat bran extract (WBE) is a food-grade soluble fibre preparation that is highly enriched in arabinoxylan–oligosaccharides. In this placebo-controlled cross-over human intervention trial, tolerance to WBE as well as the effects of WBE on faecal parameters, including faecal output and bowel habits, were studied. After a 2-week run-in period, twenty healthy volunteers consumed WBE (15 g/d in the first week, 30 g/d in the second week), oligofructose (15 g/d in the first week, 30 g/d in the second week) and placebo (for 2 weeks) in a random order, with 2-week washout periods between each treatment period. Subjects collected a 72 h stool sample for analysis of faecal output, stool pH and stool moisture concentration. Additionally, the volunteers completed questionnaires scoring occurrence frequency and distress severity of eighteen gastrointestinal (GI) symptoms. An overall GI symptom measure was calculated to analyse the overall effect of WBE and oligofructose on GI symptoms. Intake of both 30 g/d WBE and 30 g/d oligofructose lowered stool pH, indicative of increased colonic fermentation, and increased stool moisture concentration as compared with placebo intake. Intake of 30 g/d oligofructose increased the overall GI symptom measure by 1·9-fold as compared with placebo intake. Intake of WBE at doses up to 30 g/d did not affect the overall GI symptom measure. WBE exerts beneficial effects on stool characteristics and is well tolerated at up to 30 g/d. Oligofructose exerts comparable beneficial effects on stool characteristics. However, intake of 30 g/d oligofructose appears to cause GI discomfort to some extent.

This study evaluated the effect of wheat bran derived arabinoxylan‐oligosaccharides (AXOS) on fecal water (FW) cytotoxicity and genotoxicity in healthy subjects.Twenty healthy subjects performed a double‐blind, cross‐over RCT in which they ingested AXOS (10g/d) or placebo (maltodextrine, 10g/d) for 3 weeks. The intervention periods were separated by a 3‐week wash‐out period. At the end of the run‐in, intervention and wash‐out periods the subjects collected feces for 72h. Metabolite profiles were analyzed in fecal samples using GC‐MS. FW cytotoxicity was assessed using the WST‐1 assay and FW genotoxicity using the Comet Assay. Metabolite profiles were correlated to cytotoxicity and genotoxicity using cluster analysis.AXOS did not differentially affect FW cytotoxicity and genotoxicity as compared to placebo. Cluster analysis of metabolite profiles in fecal samples according to both cytotoxicity and genotoxicity revealed a separation between the high toxicity samples and the low toxicity samples. The separation according to cytotoxicity was mainly due to the presence of alcohols and acids in the high toxicity samples, while the separation according to genotoxicity was mainly due to the presence of aldehydes and branched chain fatty acids in the very genotoxic samples.Presence of specific fermentation metabolites was associated with FW cytotoxicity and genotoxicity.Support: Fund for Scientific Research‐Flanders, Belgium (FWO project G.0674.10)

Arabinoxylan-oligosaccharide samples (AXOS) present themselves as mixtures of different molecular entities with xylan backbones of different length and with different levels of arabinose substitution. Their prebiotic properties depend on their degree of polymerisation (DP) and degree of arabinose substitution (DAS). Therefore, structural characterisation of AXOS samples is important. Gas chromatography (GC) is most frequently used for quantification of AXOS levels and for determination of the average DP (avDP) and average DAS (avDAS), yet it does not provide information on the molecular mass distribution of the xylan backbones of the different AXOS entities present in the mixture. This manuscript evaluates a method based on high performance anion exchange chromatography (HPAEC) involving quantification of xylo-oligosaccharides (XOS) after either acidic or enzymic removal of arabinose substituents for its ability to determine such distribution. Results show that despite the fact that a small fraction of the arabinoses could not be removed, representative DP distributions of xylan backbones in complex AXOS samples were obtained. The similarity of the avDP determined with GC or determined with the new HPAEC method using enzymic removal of arabinose substituents confirmed this. It can be concluded that the HPAEC method involving enzymic removal of arabinoses provides useful insight in the DP distribution of the xylan backbones in complex AXOS samples.

Wheat bran extract (WBE) is a food-grade soluble fibre preparation that is highly enriched in arabinoxylan oligosaccharides. In this placebo-controlled cross-over human intervention trial, tolerance and effects on colonic protein and carbohydrate fermentation were studied. After a 1-week run-in period, sixty-three healthy adult volunteers consumed 3, 10 and 0 g WBE/d for 3 weeks in a random order, with 2 weeks' washout between each treatment period. Fasting blood samples were collected at the end of the run-in period and at the end of each treatment period for analysis of haematological and clinical chemistry parameters. Additionally, subjects collected a stool sample for analysis of microbiota, SCFA and pH. A urine sample, collected over 48 h, was used for analysis of p-cresol and phenol content. Finally, the subjects completed questionnaires scoring occurrence frequency and distress severity of eighteen gastrointestinal symptoms. Urinary p-cresol excretion was significantly decreased after WBE consumption at 10 g/d. Faecal bifidobacteria levels were significantly increased after daily intake of 10 g WBE. Additionally, WBE intake at 10 g/d increased faecal SCFA concentrations and lowered faecal pH, indicating increased colonic fermentation of WBE into desired metabolites. At 10 g/d, WBE caused a mild increase in flatulence occurrence frequency and distress severity and a tendency for a mild decrease in constipation occurrence frequency. In conclusion, WBE is well tolerated at doses up to 10 g/d in healthy adults volunteers. Intake of 10 g WBE/d exerts beneficial effects on gut health parameters.

Arabinoxylan oligosaccharides (AXOS) are studied as food compounds with prebiotic potential. Here, the impact of consumption of breads with in situ-produced AXOS on intestinal fermentation and overall gastrointestinal characteristics was evaluated in a completely randomized, double-blind, controlled, cross-over study. Twenty-seven healthy volunteers consumed 180 g of wheat/rye bread with or without in situ-produced AXOS (WR+ and WR-, respectively) daily for 3 wk. Consumption of WR+ corresponded to an AXOS intake of ~2.14 g/d. Refined wheat flour bread without AXOS (W-) (180 g/d) was provided during the 3-wk run-in and wash-out periods. At the end of each treatment period, participants collected urine for 48 h as well as a feces sample. Additionally, all participants completed a questionnaire about stool characteristics and gastrointestinal symptoms during the last week of each period. Urinary phenol and p-cresol excretions were significantly lower after WR+ intake compared to WR-. Consumption of WR+ significantly increased fecal total SCFA concentrations compared to intake of W-. The effect of WR+ intake was most pronounced on butyrate, with levels 70% higher than after consumption of W- in the run-in or wash-out period. Consumption of WR+ tended to selectively increase the fecal levels of bifidobacteria (p = 0.06) relative to consumption of W-. Stool frequency increased significantly after intake of WR+ compared to WR-. In conclusion, consumption of breads with in situ-produced AXOS may favorably modulate intestinal fermentation and overall gastrointestinal properties in healthy humans.

Background/Aims: Aspiration secondary to dysphagia is an important complication leading to increased rates of morbidity and mortality. There is scarce evidence for the effects of different bolus temperatures in swallowing behaviour in dysphagic patients [Hamdy et al, Neurogastroenterol Motil 2003;Watando et al, J Am Geriatr Soc 2004]. Moreover, there is very limited evidence for the effects of temperature on automated and complex swallowing liquid boluses on swallowing behaviour, assessed by a novel reaction time task (Mistry et al, J Physiol 2007), in healthy participants. Methods: Nineteen healthy participants (9 male, 29.7±3 years old, mean ±SEM) swallowed an intra-pharyngeal catheter with built-in pressure transducers allowing the recording of changes in pressures signal in the hypopharynx. Subjects were cued to swallow by an electrical pulse to the hand 5 ml boluses of either cold (4°C), hot (45°C) or room temperature (21°C) water, while performing 10 normal-paced swallows, 10 fast-paced swallows and 10 challenged swallows within a predetermined timewindow. Each block of (total 30) swallows were repeated twice in a pseudo-randomised manner for all temperatures. Quantitative measurements of time to the predetermined pharyngeal pressure threshold and percentage of successful challenged swallows were collected and presented as mean±SEM. Data were analysed with non-parametric Wilcoxon's test in SPSS 14. Results: Normal-paced swallows: Swallowing latencies of cold water swallows (1390 ± 80 ms) were significantly reduced compared to hot water (1545 ± 87 ms) and room temperature (1593 ± 79 ms) water swallows (z=-2.91, p<0.01 and z=-3.42, p<0.01, respectively)(Figure 1). Fast swallows: No difference was observed between the three different bolus temperatures. Challenged swallows: Contrary to the normal-paced swallows, cold bolus challenged swallows were less accurately performed (29.5 ± 3%) compared to challenged swallows with room temperature boluses (38.9 ± 3%)(z=-2.0, p=0.04) and hot temperature boluses (38.2 ± 3%) (z=-2.28, p=0.02). Conclusion: Bolus temperature plays an important role in healthy swallowing behaviour and can alter swallowing performance. Cold temperature appears to alter swallowing behaviour differentially by shortening the latency of normal-paced automated swallows, while reducing successful rates in challenged swallowing tasks. The latter maybe a consequence of speedier handling of cold bolus in the oropharynx. Based on our results, further research is warranted for the use of different temperatures in dysphagic patients to explore therapeutic effects in reducing aspiration.

Multiple studies have revealed the prebiotic activity of cereal derived arabinoxylan oligosaccharides (AXOS). This study investigated the in situ production of AXOS during bread making. In the first part, the AXOS producing capacity of different xylanases was compared in whole meal bread making. Three mesophilic xylanases originating from Bacillus subtilis, Aspergillus niger and Hypocrea jecorina, and one thermophilic xylanase from H. jecorina (HjXynA), were used in different dosages. At dosages that did not impair dough manageability, HjXynA solubilised and cleaved the arabinoxylan fraction to the largest extent, resulting in an AXOS content of 2.1% (dry basis) and an average degree of polymerisation (avDP) of 9. In the second part, the impact of HjXynA on the AXOS levels in dietary fibre enriched breads was studied. Rye or wheat bran fortified breads treated with HjXynA yielded good quality breads with AXOS levels above 2.0% with an avDP of 26 and 19, respectively.