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1.
Food Chem ; 305: 125436, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514047

RESUMO

The physicochemical properties of wheat bran have an effect on its technofunctional and nutritional profile. The possibility to induce physicochemical modifications in wheat bran using microfluidisation was investigated. An I-optimal experimental design was used to investigate the effect of microfluidisation processing parameters (pressure, number of passes, bran concentration and initial particle size) on important properties of wheat bran (particle size, microstructure, chemical composition, water retention capacity (WRC), extractability, viscosity and sedimentation). With the parameters used in this study, microfluidisation reduced wheat bran median particle size to 14.8 µm and disintegrated starch granules from the attached endosperm. This coincided with an increased extractability of starch and arabinoxylan. While the initial particle size was of minor importance, a higher pressure, larger number of passes and lower bran concentration during microfluidisation resulted in a smaller particle size, higher WRC and extractability, and an increased viscosity and stability in a 2% wheat bran suspension.

2.
ISME J ; 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31712738

RESUMO

The human gut can be viewed as a flow-through system with a short residence time, a high turnover rate and a spatial gradient of physiological conditions. As a consequence, the gut microbiota is exposed to highly fluctuating environmental determinants presented by the host and diet. Here, we assessed the fermentation and colonisation of insoluble wheat bran by faecal microbiota of three individuals at an unprecedented sampling intensity. Time-resolved 16S rRNA gene amplicon sequencing, revealed a dynamic microbial community, characterised by abrupt shifts in composition, delimiting states with a more constant community, giving rise to a succession of bacterial taxa alternately dominating the community over a 72 h timespan. Early stages were dominated by Enterobacteriaceae and Fusobacterium species, growing on the carbohydrate-low, protein rich medium to which wheat bran was supplemented. The onset of wheat bran fermentation, marked by a spike in short chain fatty acid production with an increasing butyrate proportion and an increased endo-1,4-ß-xylanase activity, corresponded to donor-dependent proportional increases of Bacteroides ovatus/stercoris, Prevotella copri and Firmicutes species, which were strongly enriched in the bran-attached community. Literature and database searches provided novel insights into the metabolic and growth characteristics underlying the observed succession and colonisation, illustrating the potency of a time-resolved analysis to increase our understanding of gut microbiota dynamics upon dietary modulations.

3.
J Agric Food Chem ; 67(40): 11198-11209, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31532988

RESUMO

The importance of inhibition sensitivity for xylanase functionality in bread making was investigated using mutants of the wild-type Bacillus subtilis xylanase (XBSTAXI), sensitive to Triticum aestivum xylanase inhibitor (TAXI). XBSNI, a mutant with reduced sensitivity to TAXI, and XBSTI, a mutant sensitive to all wheat endogenous proteinaceous inhibitors (TAXI, Xylanase Inhibiting Protein and Thaumatin-like Xylanase Inhibitor) were used. The higher inhibition sensitivity of XBSTAXI and XBSTI compared to XBSNI was associated with a respective 7- and 53-fold increase in enzyme dosage required for a maximal increase in bread loaf volume. XBSTI and XBSTAXI were only active during the mixing phase and the beginning of fermentation, while XBSNI was able to hydrolyze arabinoxylan until the end of fermentation. In spite of this difference in activity profile, no differences in loaf volume were observed for the different xylanases at optimal concentrations. Dough extensional viscosity analysis suggests that increased water availability as a result of xylanase activity favors starch-starch and starch-gluten interactions and drives the improvement in bread loaf volume.


Assuntos
Bacillus subtilis/enzimologia , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/química , Pão/análise , Endo-1,4-beta-Xilanases/antagonistas & inibidores , Endo-1,4-beta-Xilanases/química , Inibidores Enzimáticos/química , Proteínas de Plantas/química , Bacillus subtilis/química , Bacillus subtilis/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Endo-1,4-beta-Xilanases/genética , Endo-1,4-beta-Xilanases/metabolismo , Inibidores Enzimáticos/metabolismo , Farinha/análise , Manipulação de Alimentos , Hidrólise , Mutação , Proteínas de Plantas/metabolismo , Triticum/química , Triticum/metabolismo , Viscosidade
4.
J Agric Food Chem ; 67(37): 10423-10431, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31487168

RESUMO

Plants often produce antifungal peptides and proteins in response to infection. Also wheat, which is the main ingredient of bread dough, contains such components. Here, we show that while some industrial strains of the baker's yeast Saccharomyces cerevisiae can efficiently ferment dough, some other strains show much lower fermentation capacities because they are sensitive to a specific wheat protein. We purified and identified what turned out to be a thaumatin-like protein through a combination of activity-guided fractionation, cation exchange chromatography, reversed-phase HPLC, and LC-MS/MS. Recombinant expression of the corresponding gene and testing the activity confirmed the inhibitory activity of the protein.


Assuntos
Proteínas de Plantas/química , Proteínas de Plantas/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/crescimento & desenvolvimento , Triticum/química , Cromatografia Líquida , Fermentação , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/metabolismo , Saccharomyces cerevisiae/metabolismo , Espectrometria de Massas em Tandem , Triticum/genética , Triticum/metabolismo , Triticum/microbiologia
5.
Food Chem ; 295: 138-146, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174742

RESUMO

This study investigates the impact of different gelatinization characteristics of small and large barley starch granules on their enzymatic hydrolysis and sugar production during mashing. Therefore, a barley malt suspension was consecutively incubated at 45, 62, 72 and 78 °C to monitor starch behavior and enzymatic starch hydrolysis and sugar production. The combination of microscopic and rapid visco analyses showed that small starch granules persisted longer in the system and were present non-gelatinized at temperatures higher than 62 °C. HPAEC-PAD analysis showed that 8% of the total amount of starch, predominantly small granules, gelatinized at temperatures between 62 °C and 78 °C. Due to their delayed gelatinization in this system, their enzymatic hydrolysis yielded relatively more dextrins compared to what was observed for large granules. It was concluded that small granules should be taken into account when optimizing enzymatic hydrolysis of barley starch, like in brewing, distilling or bio-ethanol production.


Assuntos
Hordeum/metabolismo , Amido/química , Açúcares/metabolismo , Varredura Diferencial de Calorimetria , Dextrinas/metabolismo , Enzimas/metabolismo , Hidrólise , Tamanho da Partícula , Amido/metabolismo , Temperatura Ambiente , Viscosidade
6.
Food Funct ; 10(1): 379-396, 2019 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-30604790

RESUMO

Dietary modulation can alter the gut microbiota composition and activity, in turn affecting health. Particularly, dietary fibre rich foods, such as wheat bran, are an important nutrient source for the gut microbiota. Several processing methods have been developed to modify the functional, textural and breadmaking properties of wheat bran, which can affect the gut microbiota. We therefore studied the effect of enzyme treatment, particle size reduction and wheat kernel pearling on the faecal microbiota of ten healthy individuals. The most commonly studied health marker, associated to the gut microbiota activity is Short Chain Fatty Acid (SCFA) production. This study shows that modifying wheat bran physicochemical properties allows control over the extent and the rate of SCFA production by the faecal microbiota. Wheat bran pericarp fractions, depleted in starch and enriched in cellulose and highly branched arabinoxylans, were poorly fermentable compared to unmodified wheat bran, thus resulting in a reduced SCFA production with up to 20 mM. The nature of the SCFA, however, largely depends on the donor and can be linked to the individual's gut microbiota composition. The latter changed in an individually dependent manner in response to wheat bran modification. Some product dependent significant differences could still be identified across the ten donors. This product effect is more pronounced in the microbial community attached to the wheat bran residue as compared to the luminal microbial community. Generally, we find lower levels of Firmicutes, Bacteroidetes and Bifidobacterium and a higher abundance of Proteobacteria in the pericarp enriched wheat bran fractions, compared to unmodified wheat bran.


Assuntos
Bactérias/metabolismo , Fibras na Dieta/metabolismo , Fezes/microbiologia , Microbioma Gastrointestinal , Triticum/metabolismo , Adulto , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Fibras na Dieta/análise , Ácidos Graxos Voláteis/metabolismo , Feminino , Humanos , Masculino , Tamanho da Partícula , Triticum/química , Adulto Jovem
7.
Crit Rev Food Sci Nutr ; : 1-19, 2019 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-30632785

RESUMO

Consumption of wheat bran (WB) has been associated with improved gastrointestinal health and a reduced risk for colorectal cancer, cardiovascular diseases and metabolic disorders. These benefits are likely mediated by a combination of mechanisms, including colonic fermentation of the WB fiber, fecal bulking and the prevention of oxidative damage due to its antioxidant capacities. The relative importance of those mechanisms is not known and may differ for each health effect. WB has been modified by reducing particle size, heat treatment or modifying tissue composition to improve its technological properties and facilitate bread making processes. However, the impact of those modifications on human health has not been fully elucidated. Some modifications reinforce whereas others attenuate the health effects of coarse WB. This review summarizes available WB modifications, the mechanisms by which WB induces health benefits, the impact of WB modifications thereon and the available evidence for these effects from in vitro and in vivo studies.

8.
Food Microbiol ; 76: 135-145, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30166134

RESUMO

There is evidence that a diet low in Fermentable Oligo-, Di-, Monosaccharides And Polyols (FODMAPs) alleviates symptoms in approx. 70% of the patients suffering from irritable bowel syndrome. Through fructans, wheat containing products are a major source of FODMAPs in the western diet. Although fructans are partially degraded during dough fermentation by Saccharomyces cerevisiae invertase, wheat bread contains notable fructan levels. In this study, it was shown that Kluyveromyces marxianus strain CBS6014 can degrade more than 90% of the fructans initially present in wheat whole meal during bread making, which can be attributed to its high inulinase activity. As K. marxianus CBS6014 was not able to consume maltose during fermentation, alternative sugars (sucrose) or glucose releasing enzymes (amyloglucosidase) had to be included in the bread making recipe to ensure sufficient production of CO2 and high bread quality. Five volatile flavor compounds were produced in significantly different levels when K. marxianus CBS6014 was used as starter culture compared with the conventional S. cerevisiae bakery strain. These differences were, however, not detected when sensory analysis of the crumb was performed. This study demonstrates the potential of inulinase-producing K. marxianus strains for the production of (whole meal) breads low in FODMAPs.

9.
Environ Microbiol ; 20(9): 3406-3426, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30126070

RESUMO

The spatial organization of gut microorganisms is important with respect to their functional role in the gut ecosystem. Regional differences in the longitudinal and lateral direction are, however, not frequently studied, given the difficulty to sample these human gut regions in vivo. Particularly the insoluble food particle-associated microbiota is poorly studied. Therefore, the long-term effects of insoluble wheat bran supplementation on the composition and functionality of the gut microbial community derived from six individuals were explored in the Dietary Particle-Mucosal-Simulator of the Human Intestinal Microbial Ecosystem in vitro model. Wheat bran stimulated propionate and butyrate production and induced shifts in the luminal and mucosal microbial community composition. The insoluble wheat bran residue and the mucus layer were identified as crucial platforms in sustaining diversity by selectively enriching species, which are not thriving in the luminal environment, including Lactobacillus, Bifidobacterium and Dialister species, Roseburia faecis, Prevotella copri and Bacteroides ovatus. Despite the evident habitat preference, some parallels could be drawn between the enrichment of taxa on bran platforms and their stimulation in the luminal and mucosal communities. Removing wheat bran during the wash-out period reversed the functional effects and gave rise to a blooming of some taxa that are considered opportunistic pathogens.

10.
Artigo em Inglês | MEDLINE | ID: mdl-30143505

RESUMO

In the current study we investigated whether reducing the particle size of wheat bran affects the colonizing microbial community using batch fermentations with cecal inoculum from seven different chickens. We also investigated the effect of in-feed administration of regular wheat bran (1690 µm, WB) and wheat bran with reduced particle size (280 µm, WB280) on the cecal microbial community composition of broilers. During batch fermentation, WB280 was colonized by a lactic acid producing community (Bifidobacteriaceae and Lactobacillaceae) and by Lachnospiraceae, that contain lactic acid consuming, butyric acid producing species. The relative abundance of the Enterobacteriaceae decreased in the particle-associated community for both WB and WB280 compared to the control. In addition, the community attached to wheat bran was enriched in xylan degrading bacteria. When administered as a feed additive to broilers, WB280 significantly increased the richness of the cecal microbiota and the abundance of bacteria containing the butyryl-CoA:acetate CoA-transferase gene, a key gene involved in bacterial butyrate production, while decreasing abundances of Enterobacteriaceae family members in the ceca. Particle size reduction of wheat bran thus resulted in colonization of the bran particles by a very specific lactic acid and butyric acid producing community and can be used to steer towards beneficial microbial shifts. This can potentially increase the resilience against pathogens and increase animal performance, when the reduced particle size wheat bran is administered as feed additive to broilers.ImportancePrebiotic dietary fibres are known to improve gastrointestinal health of both humans and animals in many different ways. They can increase the bulking capacity, improve transit times and, depending on the fibre, even stimulate the growth and activity of resident beneficial bacteria. Wheat bran is a readily available byproduct of flour processing and is a highly concentrated source of (in)soluble dietary fibre. The intake of fibre rich diets has been associated with increased Firmicutes and decreased Proteobacteria numbers. Here we show that applying only 1 % of a relatively simple substrate which was technically modified using relatively simple techniques, reduces the concentration of Enterobacteriaceae This could imply that in future intervention studies one should take the particle size of dietary fibres into account.

11.
Bioresour Technol ; 263: 532-540, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29778024

RESUMO

This work aimed at investigating simultaneous hydrolysis of cellulose and in-situ foulant degradation in a cellulose fed superparamagnetic biocatalytic membrane reactor (BMRSP). In this reactor, a dynamic layer of superparamagnetic bionanocomposites with immobilized cellulolytic enzymes were reversibly immobilized on superparamagnetic polymeric membrane using an external magnetic field. The formation of a dynamic layer of bionanocomposites on the membrane helped to prevent direct membrane-foulant interaction. Due to in-situ biocatalysis, there was limited filtration resistance. Simultaneous separation of the product helped to avoid enzyme product inhibition, achieve constant reaction rate over time and 50% higher enzyme efficiency than batch reactor. Stable enzyme immobilization and the ability to keep enzyme in the system for long period helped to achieve continuous productivity at very low enzyme but high solid loading, while also reducing the extent of membrane fouling. Hence, the BMRSP paves a path for sustainable production of bioethanol from the cheaply available lignocellulose.


Assuntos
Reatores Biológicos , Celulose/metabolismo , Glucose/biossíntese , Nanopartículas de Magnetita , Enzimas Imobilizadas
12.
Food Chem ; 241: 434-442, 2018 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-28958551

RESUMO

As preharvest sprouting of wheat impairs its use in food applications, postharvest solutions for this problem are required. Due to the high kernel to kernel variability in enzyme activity in a batch of sprouted wheat, the potential of eliminating severely sprouted kernels based on density differences in NaCl solutions was evaluated. Compared to higher density kernels, lower density kernels displayed higher α-amylase, endoxylanase, and peptidase activities as well as signs of (incipient) protein, ß-glucan and arabinoxylan breakdown. By discarding lower density kernels of mildly and severely sprouted wheat batches (11% and 16%, respectively), density separation increased flour FN of the batch from 280 to 345s and from 135 to 170s and increased RVA viscosity. This in turn improved dough handling, bread crumb texture and crust color. These data indicate that density separation is a powerful technique to increase the quality of a batch of sprouted wheat.


Assuntos
Pão , Triticum , Farinha , alfa-Amilases , beta-Glucanas
13.
J Agric Food Chem ; 65(44): 9726-9734, 2017 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-29032689

RESUMO

Microbial fermentation of the viscous pulp surrounding cocoa beans is a crucial step in chocolate production. During this process, the pulp is degraded, after which the beans are dried and shipped to factories for further processing. Despite its central role in chocolate production, pulp degradation, which is assumed to be a result of pectin breakdown, has not been thoroughly investigated. Therefore, this study provides a comprehensive physicochemical analysis of cocoa pulp, focusing on pectic polysaccharides, and the factors influencing its degradation. Detailed analysis reveals that pectin in cocoa pulp largely consists of weakly bound substances, and that both temperature and enzyme activity play a role in its degradation. Furthermore, this study shows that pulp degradation by an indigenous yeast fully relies on the presence of a single gene (PGU1), encoding for an endopolygalacturonase. Apart from their basic scientific value, these new insights could propel the selection of microbial starter cultures for more efficient pulp degradation.


Assuntos
Cacau/microbiologia , Pectinas/metabolismo , Saccharomyces cerevisiae/metabolismo , Cacau/química , Cacau/metabolismo , Fermentação , Microbiologia de Alimentos , Pectinas/química , Poligalacturonase/genética , Poligalacturonase/metabolismo , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Sementes/química , Sementes/metabolismo , Sementes/microbiologia
14.
J Agric Food Chem ; 65(39): 8704-8713, 2017 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-28869377

RESUMO

Fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) are small molecules that are poorly absorbed in the small intestine and rapidly fermented in the large intestine. There is evidence that a diet low in FODMAPs reduces abdominal symptoms in approximately 70% of the patients suffering from irritable bowel syndrome. Wheat contains relatively high fructan levels and is therefore a major source of FODMAPs in our diet. In this study, a yeast-based strategy was developed to reduce FODMAP levels in (whole wheat) bread. Fermentation of dough with an inulinase-secreting Kluyveromyces marxianus strain allowed to reduce fructan levels in the final product by more than 90%, while only 56%  reduction was achieved when a control Saccharomyces cerevisiae strain was used. To ensure sufficient CO2 production, cocultures of S. cerevisiae and K. marxianus were prepared. Bread prepared with a coculture of K. marxianus and S. cerevisiae had fructan levels ≤0.2% dm, and a loaf volume comparable with that of control bread. Therefore, this approach is suitable to effectively reduce FODMAP levels in bread.


Assuntos
Pão/microbiologia , Fermentação , Kluyveromyces/metabolismo , Saccharomyces cerevisiae/metabolismo , Açúcares/metabolismo , Triticum/química , Pão/análise , Técnicas de Cocultura , Dieta , Dissacarídeos/análise , Dissacarídeos/metabolismo , Frutanos/análise , Glicosídeo Hidrolases/metabolismo , Síndrome do Intestino Irritável/dietoterapia , Monossacarídeos/análise , Monossacarídeos/metabolismo , Oligossacarídeos/análise , Oligossacarídeos/metabolismo , Polímeros/análise , Polímeros/metabolismo
15.
Carbohydr Polym ; 174: 343-351, 2017 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-28821077

RESUMO

A liquid chromatography-mass spectrometry (LC-MS) library is presented containing the relative retention times of 28 fructan oligomers and MS2 spectra of 18 of them. It includes the main representatives of all fructan classes occurring in nature and with a degree of polymerization between three and five. This library enables a rapid and unambiguous detection of these 18 fructan structures in any type of sample without the need for fructan purification or the synthesis of fructan standards. Its wide applicability is demonstrated by the analysis of fructans in a set of cereal flour samples. Marked differences were observed in the types of fructans present in oat, barley, rye, spelt and wheat flour. A putative link between the accumulation of certain fructan types and cereal phylogeny is described.

16.
Sci Rep ; 7(1): 5621, 2017 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-28717237

RESUMO

The aim of this study was to determine the impact of different wheat bran fractions on the gut microbiota and fat binding capacity to explain their differential effects on metabolic and inflammatory disorders induced by a western diet (WD) in mice. Wheat bran derived arabinoxylan oligosaccharides (AXOS), a crude fraction of wheat bran (WB), or the same wheat bran with reduced particle size (WBs) were added to the WD of mice for 8 weeks. AXOS shifted the gut microbiota composition, blunted Clostridium and Turicibacter genera and strongly promoted Bifidobacterium and Butyricicoccus genera, independently of changes in gut antimicrobial peptide expression. AXOS was the most efficient to reduce adiposity. Only WB fraction promoted fat excretion and differed from the other fractions by the capacity to increase the Akkermansia genus and to counteract gut interleukin 1 beta (IL1ß) overexpression. Strikingly, WBs promoted steatosis and adipose tissue inflammation, despite its ability -like WB- to increase bacterial diversity. In conclusion, wheat bran fractions differently affect metabolic and inflammatory disorders associated with WD feeding, depending on their particle size, their fat binding capacity and their influence on the gut microbiota. Those results might be useful to take into account in nutritional advices to control obesity.

17.
Environ Microbiol ; 19(8): 3251-3267, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28618173

RESUMO

Gut microbiota research reveals a vital role for the luminal and mucosal gut microbiota in human health. Fewer studies, however, have characterized the microbiome associated with undigested, insoluble dietary particles in the gut. These particles can act as a food source for bacteria and offer a physical platform to which they can attach. In this study, the microbiome colonizing wheat bran particles was analyzed. In a batch experiment, wheat bran particles were separately incubated with the faecal microbiota derived from 10 donors and washed after 48 h to remove loosely attached bacteria. The response of the luminal community to wheat bran and inulin, acting as a well-characterized control, was largely donor-dependent, both functionally, and with respect to the microbiome composition. Depending on the donor, wheat bran and inulin fermentation yielded proportionally higher propionate or butyrate production. Clostridium cluster XIVa and, depending on the donor, Prevotella, Roseburia, Megamonas, Bifidobacterium and Bacteroides species were enriched on the wheat bran particles. These genera include species with the documented ability to serve as primary degraders of wheat bran components and other species depending on cross-feeding to obtain their energy. Both functional groups were present in all donors, despite the large inter-individual differences.


Assuntos
Bacteroides/metabolismo , Bifidobacterium/metabolismo , Clostridium/metabolismo , Fibras na Dieta/metabolismo , Microbioma Gastrointestinal/fisiologia , Inulina/metabolismo , Prevotella/metabolismo , Bacteroides/crescimento & desenvolvimento , Bifidobacterium/crescimento & desenvolvimento , Butiratos/metabolismo , Clostridium/crescimento & desenvolvimento , Dieta , Fibras na Dieta/microbiologia , Fezes/microbiologia , Fermentação , Humanos , Prevotella/crescimento & desenvolvimento , Propionatos/metabolismo
18.
J Agric Food Chem ; 65(16): 3368-3377, 2017 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-28367622

RESUMO

Identification and use of yeast strains that are unable to consume one or more otherwise fermentable substrate types could allow a more controlled fermentation process with more flexibility regarding fermentation times. In this study, Saccharomyces cerevisiae strains with different capacities to consume substrates present in wheat were selected to investigate the impact of substrate limitation on dough fermentation and final bread volume. Results show that fermentation of dough with maltose-negative strains relies on the presence of fructan and sucrose as fermentable substrates and can be used for regular bread making. Levels of fructan and sucrose, endogenously present or added, hence determine the extent of fermentation and timing at the proofing stage. Whole meal is inherently more suitable for substrate-limited fermentation than white flour due to the presence of higher native levels of these substrates. Bread making protocols with long fermentation times are accommodated by addition of substrates such as sucrose.


Assuntos
Pão/microbiologia , Saccharomyces cerevisiae/metabolismo , Triticum/microbiologia , Pão/análise , Fermentação , Farinha/análise , Farinha/microbiologia , Frutanos/metabolismo , Maltose/metabolismo , Sacarose/metabolismo , Fatores de Tempo , Triticum/metabolismo
19.
Nutrients ; 9(1)2017 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-28117694

RESUMO

Wheat bran (WB) is a constituent of whole grain products with beneficial effects for human health. Within the human colon, such insoluble particles may be colonized by specific microbial teams which can stimulate cross-feeding, leading to a more efficient carbohydrate fermentation and an increased butyrate production. We investigated the extent to which WB fractions with different properties affect the fermentation of other carbohydrates in the colon. Ten healthy subjects performed four test days, during which they consumed a standard breakfast supplemented with 10 g 13C-inulin. A total of 20 g of a WB fraction (unmodified WB, wheat bran with a reduced particle size (WB RPS), or de-starched pericarp-enriched wheat bran (PE WB)) was also added to the breakfast, except for one test day, which served as a control. Blood samples were collected at regular time points for 14 h, in order to measure 13C-labeled short-chain fatty acid (SCFA; acetate, propionate and butyrate) concentrations. Fermentation of 13C-inulin resulted in increased plasma SCFA for about 8 h, suggesting that a sustained increase in plasma SCFA can be achieved by administering a moderate dose of carbohydrates, three times per day. However, the addition of a single dose of a WB fraction did not further increase the 13C-SCFA concentrations in plasma, nor did it stimulate cross-feeding (Wilcoxon signed ranks test).


Assuntos
Fibras na Dieta/uso terapêutico , Disbiose/prevenção & controle , Ácidos Graxos Voláteis/metabolismo , Microbioma Gastrointestinal , Mucosa Intestinal/metabolismo , Inulina/metabolismo , Prebióticos , Adulto , Biomarcadores/sangue , Biomarcadores/metabolismo , Desjejum , Isótopos de Carbono , Estudos Cross-Over , Fibras na Dieta/metabolismo , Disbiose/sangue , Disbiose/metabolismo , Disbiose/microbiologia , Ácidos Graxos Voláteis/sangue , Feminino , Fermentação , Humanos , Absorção Intestinal , Mucosa Intestinal/microbiologia , Masculino , Tamanho da Partícula , Período Pós-Prandial , Reprodutibilidade dos Testes , Método Simples-Cego , Adulto Jovem
20.
Food Chem ; 218: 89-98, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-27719961

RESUMO

It is generally believed that maltose drives yeast-mediated bread dough fermentation. The relative importance of fructose and glucose, released from wheat fructan and sucrose by invertase, compared to maltose is, however, not documented. This is surprising given the preference of yeast for glucose and fructose over maltose. This study revealed that, after 2h fermentation of wheat flour dough, about 44% of the sugars consumed were generated by invertase-mediated degradation of fructan, raffinose and sucrose. The other 56% were generated by amylases. In whole meal dough, 70% of the sugars consumed were released by invertase activity. Invertase-mediated sugar release seems to be crucial during the first hour of fermentation, while amylase-mediated sugar release was predominant in the later stages of fermentation, which explains why higher amylolytic activity prolonged the productive fermentation time only. These results illustrate the importance of wheat fructan and sucrose content and their degradation for dough fermentations.


Assuntos
Pão/análise , Fermentação , Farinha/análise , Frutanos/análise , Amido/análise , Amilases/análise , Amilases/metabolismo , Frutanos/metabolismo , Maltose/análise , Maltose/metabolismo , Saccharomyces cerevisiae/metabolismo , Amido/metabolismo , Sacarose/análise , Sacarose/metabolismo , Triticum/metabolismo , beta-Frutofuranosidase/análise , beta-Frutofuranosidase/metabolismo
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