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1.
Foods ; 9(12)2020 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-33260871

RESUMO

Wheat bran consumption is associated with several health benefits, but its incorporation into food products remains low because of sensory and technofunctional issues. Besides, its full beneficial potential is probably not achieved because of its recalcitrant nature and inaccessible structure. Particle size reduction can affect both technofunctional and nutrition-related properties. Therefore, in this study, wet milling and cryogenic milling, two techniques that showed potential for extreme particle size reduction, were used. The effect of the milling techniques, performed on laboratory and large scale, was evaluated on the structure and physicochemical properties of wheat bran. With a median particle size (d50) of 6 µm, the smallest particle size was achieved with cryogenic milling on a laboratory scale. Cryogenic milling on a large scale and wet milling on laboratory and large scale resulted in a particle size reduction to a d50 of 28-38 µm. In the milled samples, the wheat bran structure was broken down, and almost all cells were opened. Wet milling on laboratory and large scale resulted in bran with a more porous structure, a larger surface area and a higher capacity for binding water compared to cryogenic milling on a large scale. The extensive particle size reduction by cryogenic milling on a laboratory scale resulted in wheat bran with the highest surface area and strong water retention capacity. Endogenous enzyme activity and mechanical breakdown during the different milling procedures resulted in different extents of breakdown of starch, sucrose, ß-glucan, arabinoxylan and phytate. Therefore, the diverse impact of the milling techniques on the physicochemical properties of wheat bran could be used to target different technofunctional and health-related properties.

2.
Carbohydr Polym ; 241: 116262, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32507220

RESUMO

The effect of wheat bran on starch gelatinization temperature was investigated. Dynamic water vapour sorption and water retention capacity experiments showed that bran bound up to 3 times more water than starch. However, examining starch gelatinization in starch-bran-water mixtures with differential scanning calorimetry showed that the effect of substituting starch by bran differed from that of moving into a regime of limiting water. Modelling the effect of the mixture composition on starch gelatinization behavior indicated that the onset (To) and peak (Tp) gelatinization temperatures were positively impacted by the bran concentration in water. The conclusion temperature (Tc) was negatively affected by the water content. Fractionation experiments demonstrated that the increased To and Tp were mainly caused by the extractable wheat bran components, such as potassium and phosphorus, which decrease the plasticization capacity of the solvent. The mechanism behind our observations was explained with the side-chain liquid-crystalline polymeric model for starch.

3.
Foods ; 9(6)2020 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-32512729

RESUMO

The potential of extrusion-cooking to change the physicochemical characteristics of wheat bran, increase its nutritional value and decrease its recalcitrance towards fermentation was investigated in this study. The conditions in a twin-screw extruder were varied by changing screw configuration, moisture content and barrel temperature. The former was not previously investigated in studies on bran extrusion. Extrusion-cooking resulted in an increased water-holding capacity and extract viscosity of bran, suggesting shear-induced structure degradation and structure loosening due to steam explosion at the extruder outlet. Modelling showed that the extent of these modifications mainly correlates with the amount of specific mechanical energy (SME) input, which increases with an increasing number of work sections in the screw configuration and a decreasing moisture content and barrel temperature. Extrusion led to solubilisation of arabinoxylan and ferulic acid. Moreover, it led to starch melting and phytate degradation. Upon fermentation of the most modified sample using a human faecal inoculum, small numeric pH decreases and short-chain fatty acid production increases were observed compared to the control bran, while protein fermentation was decreased. Overall, extrusion-cooking can improve the nutrition-related properties of wheat bran, making it an interesting technique for the modification of bran before further use or consumption as an extruded end product.

4.
Food Chem ; 331: 127292, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32559599

RESUMO

Food supplementation with vitamin A is an efficient strategy to combat vitamin A deficiency. The stability of vitamin A during cooking and storage is, however, low. We here show that cereal bran protects retinyl palmitate (RP) during simmering and storage. Native wheat bran stabilized RP the most during simmering. About 75% RP was recovered after 120 min of cooking, while all RP was lost after 80 min in the absence of bran. Heat-treated rice bran protected RP the best during forced storage, with a 35% recovery after 8 weeks. RP was degraded entirely in the absence of bran in less than one week. Results suggested that the physical entrapment of oil within the large wheat bran particles protects RP from the action of water and pro-oxidants during simmering. During storage, the high amount and diversity of lipid components present in rice bran are presumably responsible for its protective effect.


Assuntos
Culinária , Fibras na Dieta/análise , Armazenamento de Medicamentos , Grão Comestível/química , Vitamina A/química , Diterpenos/química , Espécies Reativas de Oxigênio/química , Vitamina A/análogos & derivados , Água/química
5.
Plant J ; 103(4): 1477-1489, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32412127

RESUMO

The architecture of endosperm cell walls in Hordeum vulgare (barley) differs remarkably from that of other grass species and is affected by germination or malting. Here, the cell wall microstructure is investigated using (bio)chemical analyses, cryogenic scanning electron microscopy (cryo-SEM) and confocal laser scanning microscopy (CLSM) as the main techniques. The relative proportions of ß-glucan, arabinoxylan and pectin in cell walls were 61, 34 and 5%, respectively. The average thickness of a single endosperm cell wall was 0.30 µm, as estimated by the cryo-SEM analysis of barley seeds, which was reduced to 0.16 µm after malting. After fluorescent staining, 3D confocal multiphoton microscopy (multiphoton CLSM) imaging revealed the complex cell wall architecture. The endosperm cell wall is composed of a structure in which arabinoxylan and pectin are colocalized on the outside, with ß-glucan depositions on the inside. During germination, arabinoxylan and ß-glucan are hydrolysed, but unlike ß-glucan, arabinoxylan remains present in defined cell walls in malt. Integrating the results, an enhanced model for the endosperm cell walls in barley is proposed.

6.
Food Chem ; 325: 126828, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32413686

RESUMO

The molecular mobility of water and biopolymers in wheat dough and the influence of xylanases thereon was investigated with time domain proton nuclear magnetic resonance relaxometry. To reduce the complexity, model systems containing starch, gluten and/or water-unextractable arabinoxylan (WU-AX) were used. In the starch-WU-AX-water model, starch binds water fast but less strong compared to WU-AX, resulting in water withdrawal from starch during resting. In contrary, WU-AX did not affect the water distribution in a gluten-WU-AX-water system, despite the higher water retention capacity (WRC) of WU-AX compared to gluten. In a starch-gluten-WU-AX-water model and in wheat flour, water was distributed over the different constituents including WU-AX. Addition of xylanase reduced the WRC of WU-AX, resulting in a release of water. Therefore, the beneficial effect of xylanase on dough and bread quality can, in part, be attributed to the redistribution of water, initially bound by WU-AX, between the other flour constituents.

7.
Int J Food Microbiol ; 326: 108648, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32387971

RESUMO

Consumption of fructan-containing cereal products is considered beneficial for most people, but not for those suffering from irritable bowel syndrome (IBS), as they should avoid the consumption of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (acronym: FODMAP). Controlling fructan levels in cereal products is not trivial. However, controlling yeast invertase-mediated hydrolysis of fructan during dough fermentation might offer a handle to modulate fructan concentrations. In this work, the variability in invertase activity and substrate specificity in an extensive set of industrial Saccharomyces cerevisiae strains is investigated. Analysis showed a high variability in the capacity of these strains to hydrolyse sucrose and fructo-oligosaccharides. Industrial yeast strains with a high activity towards fructo-oligosaccharides efficiently reduced wheat grain fructans during dough fermentation to a final fructan level of 0.3% dm, whereas strains with a low invertase activity yielded fructan levels around 0.6% dm. The non-bakery strains produced lower levels of CO2 in fermenting dough resulting in lower loaf volumes. However, CO2 production and loaf volume could be increased by the addition of 3% glucose. In conclusion, this study shows that variation in yeast invertase activity and specificity can be used to modulate the fructan content in bread, allowing the production of low FODMAP breads, or alternatively, breads with a higher soluble dietary fibre content.


Assuntos
Dissacarídeos/análise , Monossacarídeos/análise , Oligossacarídeos/análise , Saccharomyces cerevisiae/enzimologia , Triticum/química , beta-Frutofuranosidase/metabolismo , Pão/análise , Fermentação , Frutanos/análise , Frutanos/metabolismo , Hidrólise , Síndrome do Intestino Irritável/patologia , Sacarose/metabolismo , Fermento Seco
8.
Carbohydr Polym ; 239: 116257, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32414445

RESUMO

A satisfying mouthfeel is essential for the production of non-alcoholic, low-alcohol beers and light beers. This paper highlights the importance of non-starch carbohydrates as mouthfeel contributors in this context. Beers were brewed with a substitution of 20 % barley malt grits by non-malted barley, rye or oats compared to a control. For the beer brewed with rye, both a 53 % increase in arabinoxylan content and an increase in the average degree of polymerization from 29 to 50 were observed. Compared to the control beer (1.48 mm²/s), viscosity was the highest for the rye beer (1.85 mm²/s). Multivariate data analysis underlined the role of arabinoxylan content and degree of polymerization as determinants of beer viscosity. A sensory panel distinguished a low-alcohol rye beer as the one with increased fullness compared to a 100 % malt beer. These experiments suggest that rye addition can be used as a strategy to increase the beer fullness.

9.
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.


Assuntos
Fibras na Dieta/análise , Triticum/química , Endosperma/química , Tamanho da Partícula , Amido , Viscosidade , Água , Xilanos
10.
ISME J ; 14(2): 584-596, 2020 02.
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.


Assuntos
Bactérias , Fezes/microbiologia , Microbioma Gastrointestinal , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Biofilmes , Butiratos/metabolismo , Dieta , Fibras na Dieta/metabolismo , Ecossistema , Ácidos Graxos Voláteis/metabolismo , Fermentação , Microbioma Gastrointestinal/genética , Microbioma Gastrointestinal/fisiologia , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Metagenômica , RNA Ribossômico 16S/genética
11.
Crit Rev Food Sci Nutr ; 60(7): 1104-1122, 2020.
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.


Assuntos
Dieta Saudável , Fibras na Dieta , Triticum/química , Colo/metabolismo , Colo/microbiologia , Fezes/química , Fermentação , Humanos
12.
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
13.
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
14.
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 , Viscosidade
15.
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
16.
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.


Assuntos
Pão/análise , Fermentação , Frutanos/metabolismo , Kluyveromyces/metabolismo , Triticum/metabolismo , Triticum/microbiologia , Pão/microbiologia , Dieta/efeitos adversos , Humanos , Síndrome do Intestino Irritável/prevenção & controle , Kluyveromyces/enzimologia , Maltose/metabolismo , Monossacarídeos/análise , Saccharomyces cerevisiae/metabolismo , Sacarose/metabolismo , Paladar
17.
Environ Microbiol ; 20(9): 3406-3426, 2018 09.
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.


Assuntos
Bactérias/metabolismo , Butiratos/metabolismo , Colo/microbiologia , Fibras na Dieta/metabolismo , Microbioma Gastrointestinal , Mucosa Intestinal/microbiologia , Propionatos/metabolismo , Adulto , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bacteroides , Bifidobacterium , Colo/metabolismo , Dieta , Fezes/microbiologia , Feminino , Humanos , Mucosa Intestinal/metabolismo , Masculino , Microbiota , Pessoa de Meia-Idade , Membrana Mucosa , Prevotella , Adulto Jovem
18.
Appl Environ Microbiol ; 84(21)2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30143505

RESUMO

In the present study, we investigated whether reducing the particle size of wheat bran affects the colonizing microbial community using batch fermentations with cecal inocula from seven different chickens. We also investigated the effect of in-feed administration of regular wheat bran (WB; 1,690 µm) and wheat bran with reduced particle size (WB280; 280 µm) 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 abundances of the Enterobacteriaceae decreased in the particle-associated communities for both WB and WB280 compared to that of 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-coenzyme A (CoA):acetate CoA-transferase gene, a key gene involved in bacterial butyrate production, while decreasing the abundances of Enterobacteriaceae family members in the ceca. Particle size reduction of wheat bran thus resulted in the colonization of the bran particles by a very specific lactic acid- and butyric acid-producing community and can be used to steer toward 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 a feed additive to broilers.IMPORTANCE Prebiotic dietary fibers are known to improve the gastrointestinal health of both humans and animals in many different ways. They can increase the bulking capacity, improve transit times, and, depending on the fiber, even stimulate the growth and activity of resident beneficial bacteria. Wheat bran is a readily available by-product of flour processing and is a highly concentrated source of (in)soluble dietary fiber. The intake of fiber-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 fibers into account.


Assuntos
Ração Animal/microbiologia , Galinhas/microbiologia , Fibras na Dieta/análise , Enterobacteriaceae/crescimento & desenvolvimento , Microbioma Gastrointestinal , Lactobacillaceae/crescimento & desenvolvimento , Ração Animal/análise , Animais , Ácido Butírico/metabolismo , Ceco/microbiologia , Galinhas/metabolismo , Fibras na Dieta/metabolismo , Fibras na Dieta/microbiologia , Fermentação , Ácido Láctico/metabolismo , Lactobacillaceae/metabolismo , Tamanho da Partícula , Triticum/química , Triticum/metabolismo , Triticum/microbiologia
19.
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
20.
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
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