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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.
Food Chem ; 302: 125274, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31404869

RESUMO

Limited hydrolysis of rice endosperm protein isolate was carried out with acid and neutral endoproteases to evaluate the relationship between degree of hydrolysis and techno-functional properties. The highest studied degree of hydrolysis was 5.4% corresponding to 55.2% protein solubility. Solubility increased as a function of degree of hydrolysis with higher efficiency by acid endoprotease. Colloidal stability of the protein suspensions steadily increased with increasing degree of hydrolysis. Higher colloidal stability values were achieved by neutral endoprotease (31-89%) compared to that by acid endoprotease (20-75%). On the other hand, the absolute values of zeta potential and surface hydrophobicity decreased as a function of degree of hydrolysis leading to higher values by neutral endoprotease (-21.4 mV and 21.7 mV) than by acid endoprotease (-813.4 mV and 11.7 mV). Foaming, gel formation and water holding properties improved only until degree of hydrolysis values of 1.5% (neural endoprotease) and 1.9% (acid endoprotease).


Assuntos
Endosperma/química , Oryza/química , Proteínas de Plantas/química , Concentração de Íons de Hidrogênio , Hidrólise , Interações Hidrofóbicas e Hidrofílicas , Peptídeo Hidrolases/metabolismo , Proteínas de Plantas/metabolismo , Solubilidade
4.
Int J Mol Sci ; 20(8)2019 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-31003566

RESUMO

The development of prebiotic fibers requires fast high-throughput screening of their effects on the gut microbiota. We demonstrated the applicability of a mictotiter plate in the in vitro fermentation models for the screening of potentially-prebiotic dietary fibers. The effects of seven rye bran-, oat- and linseed-derived fiber preparations on the human fecal microbiota composition and short-chain fatty acid production were studied. The model was also used to study whether fibers can alleviate the harmful effects of amoxicillin-clavulanate on the microbiota. The antibiotic induced a shift in the bacterial community in the absence of fibers by decreasing the relative amounts of Bifidobacteriaceae, Bacteroidaceae, Prevotellaceae, Lachnospiraceae and Ruminococcaceae, and increasing proteobacterial Sutterilaceae levels from 1% to 11% of the total microbiota. The fermentation of rye bran, enzymatically treated rye bran, its insoluble fraction, soluble oat fiber and a mixture of rye fiber:soluble oat fiber:linseed resulted in a significant increase in butyrate production and a bifidogenic effect in the absence of the antibiotic. These fibers were also able to counteract the negative effects of the antibiotic and prevent the decrease in the relative amount of bifidobacteria. Insoluble and soluble rye bran fractions and soluble oat fiber were the best for controlling the level of proteobacteria at the level below 2%.


Assuntos
Fibras na Dieta/metabolismo , Ácidos Graxos Voláteis/biossíntese , Microbioma Gastrointestinal/efeitos dos fármacos , Prebióticos/administração & dosagem , Bacteroidetes/efeitos dos fármacos , Bacteroidetes/isolamento & purificação , Bifidobacterium/efeitos dos fármacos , Bifidobacterium/isolamento & purificação , Ácidos Graxos Voláteis/administração & dosagem , Ácidos Graxos Voláteis/química , Fezes/química , Fermentação , Humanos , Proteobactérias/efeitos dos fármacos , Proteobactérias/isolamento & purificação
5.
Food Chem ; 289: 103-111, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30955591

RESUMO

The effect of three combinations of bioprocessing methods by lactic acid fermentation, cell wall hydrolyzing enzymes and phytase on the biochemical (protein, fat, carbohydrate composition) and technofunctional properties (protein solubility, emulsifying and foaming properties) of wheat bran protein isolates were evaluated. The bioprocessing increased the protein (up to 80%) and fat content (up to 22.8%) in the isolates due to the degradation of starch and soluble pentosans. Additional proteins, globulin 3A and 3C, chitinase, ß-amylase and LMW glutenins, were identified from the electrophoretic pattern of the protein isolate bioprocessed with added enzymes. Generally, the bioprocessed protein isolate had lower protein solubility and stronger net charge in pH below 7, when compared to the protein isolate made without bioprocessing. The emulsifying properties of the protein isolates were not affected by bioprocessing. However, the foaming stability of the protein isolates was nearly doubled by bioprocessing with cell wall hydrolyzing enzymes and phytase.


Assuntos
Fibras na Dieta/metabolismo , Proteínas de Plantas/química , Quitinases/química , Quitinases/isolamento & purificação , Quitinases/metabolismo , Eletroforese em Gel de Poliacrilamida , Hidrólise , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/metabolismo , Estabilidade Proteica , Solubilidade , Amido/metabolismo , beta-Amilase/química , beta-Amilase/isolamento & purificação , beta-Amilase/metabolismo
6.
J Agric Food Chem ; 66(40): 10394-10399, 2018 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-30253094

RESUMO

In legumes such as faba bean, phytic acid can form very stable complexes with proteins, thus hindering their accessibility for gastrointestinal digestion. This study was set up to investigate the influence of enzymatic phytase treatment and lactic acid bacteria fermentation ( Lactobacillus plantarum VTT E-78076) on phytic acid reduction as well as on the protein quality and digestibility of faba bean flour. The soluble protein and release of free amino acids from faba bean flours were followed during a simulated in vitro digestion process. Phytase treatment efficiently reduced the amount of phytic acid in faba bean flour up to 89% degradation. The reduction of phytic acid content caused a shift in the protein solubility curve, showing higher solubility levels at low pH. Further, the enzyme-aided degradation of phytic acid considerably enhanced the digestibility of faba bean proteins (dose-dependent) and the release of free amino nitrogen in the first stage of digestion (gastric phase). The results propose the benefits of phytase treatment in plant-based foods where the phytic acid content may hinder the digestion of protein.


Assuntos
Manipulação de Alimentos/métodos , Lactobacillus plantarum/metabolismo , Ácido Fítico/metabolismo , Proteínas de Plantas/metabolismo , Vicia faba/metabolismo , Vicia faba/microbiologia , Aminoácidos/análise , Aminoácidos/metabolismo , Digestão , Fermentação , Humanos , Ácido Fítico/análise , Proteínas de Plantas/análise , Vicia faba/química
7.
Food Res Int ; 107: 297-305, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29580489

RESUMO

Plant cell cultures from cloudberry, lingonberry and stoneberry were studied in terms of their nutritional properties as food. Carbohydrate, lipid and protein composition, in vitro protein digestibility and sensory properties were investigated. Dietary fibre content varied between 21.2 and 36.7%, starch content between 0.3 and 1.3% and free sugar content between 17.6 and 33.6%. Glucose and fructose were the most abundant sugars. High protein contents between 13.7 and 18.9% were recorded and all samples had a balanced amino acid profile. In vitro protein digestion assay showed hydrolysis by digestive enzymes in fresh cells but only limited hydrolysis in freeze-dried samples. The lipid analysis indicated that the berry cells were rich sources of essential, polyunsaturated fatty acids. In sensory evaluation, all fresh berry cells showed fresh odour and flavour. Fresh cell cultures displayed a rather sandy, coarse mouthfeel, whereas freeze-dried cells melted quickly in the mouth. All in all the potential of plant cells as food was confirmed.

8.
Food Chem ; 231: 87-95, 2017 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-28450027

RESUMO

Oat and faba bean protein isolates were treated with transglutaminase from Streptomyces mobaraensis and tyrosinase from Trichoderma reesei to modify the colloidal properties of protein particles in order to improve their colloidal stability and foaming properties. Transglutaminase crosslinked faba bean protein extensively already with 10nkat/g enzyme dosage. Oat protein was crosslinked to some extent with transglutaminase with higher dosages (100 and 1000nkat/g). Transglutaminase increased the absolute zeta-potential values and reduced the particle size of oat protein particles. As a result, the colloidal stability and foaming properties were improved. Tyrosinase had limited crosslinking ability on both plant protein materials. Tyrosinase greatly reduced the solubility of oat protein despite limited crosslinking. Tyrosinase did not have effect on zeta-potential or colloidal stability of either protein, but it impaired foaming properties of both. Thus, the crosslinking enzymes studied caused significantly different end product functionality, presumably due to the different mechanism of action.


Assuntos
Avena , Proteínas de Plantas , Vicia faba , Monofenol Mono-Oxigenase , Solubilidade
9.
J Agric Food Chem ; 65(9): 1854-1864, 2017 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-28206756

RESUMO

Cereal bran is an important source of dietary fiber and bioactive compounds, such as phenolic acids. We aimed to study the phenolic acid metabolism of native and bioprocessed rye bran fortified refined wheat bread and to elucidate the microbial metabolic route of phenolic acids. After incubation in an in vitro colon model, the metabolites were analyzed using two different methods applying mass spectrometry. While phenolic acids were released more extensively from the bioprocessed bran bread and ferulic acid had consistently higher concentrations in the bread type during fermentation, there were only minor differences in the appearance of microbial metabolites, including the diminished levels of certain phenylacetic acids in the bioprocessed bran. This may be due to rye matrix properties, saturation of ferulic acid metabolism, or a rapid formation of intermediary metabolites left undetected. In addition, we provide expansion to the known metabolic pathways of phenolic acids.


Assuntos
Bactérias/metabolismo , Pão/análise , Colo/microbiologia , Alimentos Fortificados/análise , Hidroxibenzoatos/metabolismo , Secale/metabolismo , Bactérias/química , Colo/metabolismo , Fibras na Dieta/análise , Fermentação , Microbioma Gastrointestinal , Humanos , Hidroxibenzoatos/química , Modelos Biológicos , Secale/microbiologia
10.
Carbohydr Polym ; 154: 305-12, 2016 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-27577922

RESUMO

The objective was to evaluate the potential of birch xylan as a food hydrocolloid and dietary fibre. High-molecular weight xylan was isolated from birch kraft pulp by alkaline extraction, and enzymatically hydrolysed. Fermentability of xylans was evaluated using an in vitro colon model and performance as a hydrocolloid was studied in low-fat acid milk gels (1.5% and 3% w/w). Texture of the gels and water holding capacity of xylans were compared with inulin, fructooligosaccharide and xylooligosaccharide. Xylans showed slower fermentation rate by faecal microbiota than the references. Xylan-enriched acid milk gels (3% w/w) had improved water holding capacity (over 2-fold) and showed lower spontaneous syneresis, firmness and elasticity when compared to control (no hydrocolloids) or to references. In conclusion, birch xylan improved texture of low-fat acid milk gel applications, and the slow in vitro fermentation rate predicts lower incidence of intestinal discomfort in comparison to the commercial references.


Assuntos
Betula/química , Coloides/química , Géis/química , Leite/química , Xilanos/química , Animais , Fibras na Dieta , Fermentação , Humanos , Hidrólise , Madeira/química
11.
Foods ; 5(2)2016 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-28231119

RESUMO

Disintegration of rye and wheat breads during in vitro gastric digestion and its relation to the postprandial glucose and insulin responses of the breads was studied. Breads with distinct composition and texture characteristics were prepared with refined or wholegrain wheat and rye flour by using either straight dough or sourdough process. After chewing and gastric digestion in vitro, 100% wholemeal and refined rye breads prepared by sourdough method were disintegrated to a much lower extent than the wheat breads, having more bread digesta particles with size over 2 or 3 mm. Microstructure of the digesta particles of rye sourdough bread revealed more aggregated and less degraded starch granules when compared to refined wheat bread. The postprandial insulin responses, but not those of glucose, to the 100% rye breads made with sourdough method were lower than the responses to the refined wheat bread. Addition of gluten or bran in rye sourdough bread increased insulin response. PCA (Principal Component Analysis) analysis confirmed that the insulin response had a negative correlation with the number of larger particles after in vitro digestion as well as amount of soluble fiber and sourdough process. Since the high relative proportion of large sized particles after chewing and in vitro gastric digestion was associated with low postprandial insulin responses, the analysis of structural disintegration in vitro is proposed as a complementary tool in predicting postprandial physiology.

12.
J Agric Food Chem ; 63(39): 8685-93, 2015 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-26365885

RESUMO

Besides providing dietary fiber, wheat bran is a recognized source of protein and is considered a very valuable substitute for other protein-rich sources in the food and feed industry. Nonetheless, several factors affect protein bioavailability, including bran's layered structure. This study showed the influence on the release and protein modification of wheat bran of different bioprocessing methods involving the activation of endogenous enzymes of bran, the addition of an enzyme mixture having carbohydrase activity, and microbial fermentation. Bioprocessing in acidic conditions significantly enhanced the solubilization of protein from wheat bran, reaching the highest value in the treatment where the sole endogenous protease activity was activated. Bioprocessing through controlled fermentation allowed a more intense proteolysis and strongly impacted the in vitro digestibility of proteins. The combined use of starter cultures and cell-wall-degrading enzymes was characterized by the highest increase of phytase activity and total phenols.


Assuntos
Fibras na Dieta/análise , Manipulação de Alimentos/métodos , Glicosídeo Hidrolases/química , Lactobacillus brevis/metabolismo , Saccharomycetales/metabolismo , Triticum/microbiologia , Fibras na Dieta/microbiologia , Digestão , Fermentação , Valor Nutritivo , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Triticum/química , Triticum/metabolismo
13.
J Agric Food Chem ; 63(11): 2997-3003, 2015 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-25739320

RESUMO

Pectinase treatment was used to facilitate protein recovery from defatted rapeseed (Brassica rapa) cold-pressing residue in water-lean conditions and without pH adjustment. Effect of extraction pH on protein yield and physiochemical properties of the protein concentrates was assessed. Enzymatic hydrolysis of carbohydrates was feasible at high (40%) solid content and improved protein recovery at pH 6. Comparable protein yields (40-41% of total protein) from enzyme-aided water extraction (pH 6) and nonenzymatic alkaline extraction (pH10) at 10% solid content suggested that after enzymatic treatment, rapeseed protein could be extracted without exposure to alkali. However, water extraction required dilute conditions, whereas alkaline extraction was feasible also at 20% solid content. The water extracts possessed better protein solubility, higher ζ-potential, and smaller particle size than isoelectric precipitates from alkaline extraction, indicating higher dispersion stability. This is suggested to be mediated by electrostatic interactions between proteins and pectic carbohydrates in the water extracts.


Assuntos
Brassica rapa/química , Proteínas de Plantas/química , Proteínas de Plantas/isolamento & purificação , Poligalacturonase/química , Biocatálise , Concentração de Íons de Hidrogênio , Solubilidade , Resíduos/análise
14.
J Agric Food Chem ; 62(32): 7989-97, 2014 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-25039585

RESUMO

Cell-wall- and pectin-degrading enzyme preparations were used to enhance extractability of proteins from rapeseed press cake. Rapeseed press cakes from cold pressing of intact Brassica rapa and partially dehulled Brassica napus seeds, containing 36-40% protein and 35% carbohydrates, were treated with pectinolytic (Pectinex Ultra SP-L), xylanolytic (Depol 740L), and cellulolytic (Celluclast 1.5L) enzyme preparations. Pectinex caused effective disintegration of embryonic cell walls through hydrolysis of pectic polysaccharides and glucans and increased protein extraction by up to 1.7-fold in comparison to treatment without enzyme addition. Accordingly, 56% and 74% of the total protein in the intact and dehulled press cakes was extracted. Light microscopy of the press cakes suggested the presence of pectins colocalized with proteins inside the embryo cells. Hydrolysis of these intracellular pectins and deconstruction of embryonic cell walls during Pectinex treatment were concluded to relate with enhanced protein release.


Assuntos
Brassica napus/química , Brassica rapa/química , Parede Celular/metabolismo , Glicosídeo Hidrolases/metabolismo , Proteínas de Plantas/isolamento & purificação , Polissacarídeos/metabolismo , Sementes/química , Ração Animal/análise , Brassica napus/citologia , Brassica rapa/citologia , Proteínas na Dieta/química , Proteínas na Dieta/isolamento & purificação , Finlândia , Manipulação de Alimentos , Hidrólise , Microscopia de Fluorescência , Epiderme Vegetal/química , Epiderme Vegetal/citologia , Proteínas de Plantas/química , Sementes/citologia , Solubilidade
15.
Mol Nutr Food Res ; 58(3): 635-46, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24115517

RESUMO

SCOPE: The cross-linking of proteins by enzymes to form high-molecular-weight protein, aggregates can be used to tailor the technological or physiological functionality of food products. Aggregation of dietary proteins by food processing may promote allergic sensitization, but the effects of enzymatic cross-linking of dietary proteins on the allergenic potential of food are not known. In this study, the bioavailability and the sensitizing or tolerizing potential of peanut proteins (PE) cross-linked with microbial tyrosinase from Trichoderma reesei and mushroom tyrosinase from Agaricus bisporus, were investigated. METHODS AND RESULTS: The impact of cross-linking of PE on the in vitro bioavailability of fluorescein isothiocyanate-labeled peanut proteins was tested in a Caco-2 cell monolayer and by competitive ELISA. The in vivo allergenicity or capacity to induce oral tolerance in mice were measured by serum levels of PE-specific antibodies and T cell cytokine production after exposure to PE and cross-linked PE. CONCLUSION: Enzymatic processing of peanut proteins by the two tyrosinases increased the bioavailability of major peanut allergen Ara h 2, but did not significantly change the allergenic or tolerizing properties of peanut. Enzymatic treatment of peanut proteins yielded cross-linked proteins with preserved molecular and immunological features of peanut allergens.


Assuntos
Arachis/imunologia , Hipersensibilidade a Amendoim/imunologia , Proteínas de Plantas/química , Proteínas de Plantas/imunologia , Albuminas 2S de Plantas/metabolismo , Animais , Antígenos de Plantas/metabolismo , Disponibilidade Biológica , Células CACO-2 , Reagentes para Ligações Cruzadas/química , Modelos Animais de Doenças , Epitopos/metabolismo , Feminino , Manipulação de Alimentos , Glicoproteínas/metabolismo , Humanos , Imunização , Imunoglobulina E/metabolismo , Camundongos Endogâmicos C3H , Monofenol Mono-Oxigenase/química , Proteínas de Plantas/metabolismo , Proteínas de Plantas/farmacocinética
16.
Food Microbiol ; 37: 69-77, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24230475

RESUMO

Wheat bran is nutritionally an important source of dietary fibre, vitamins and minerals, but its negative influence on dough rheology, texture and sensory quality of bread limits its use in bread baking. The current study aimed at improving the technological functionality of bran by bioprocessing Wheat bran of different particle size (750, 400, 160, 50 µm) was fermented 8 h or 24 h with Lactobacillus brevis E95612 and Kazachstania exigua C81116 with or without addition of enzyme mixture with various carbohydrase activities. Kinetics of growth and acidification showed that the growth of the starters was enhanced in the presence of enzymes in bran having particle size of 160 and 50 µm. Fermentation was critical to improve dough stability and volume of bran enriched breads, whereas addition of enzymes had the most significant effect in improving bread shelf-life. Wheat bread containing 160 µm bran fermented 8 h with enzymes had mild flavour, the highest volume and shelf-life. Reduction of particle size increased perceived smoothness of mouthfeel but provided darker colour in bran-containing breads. The short 8 h bioprocessing, with or without enzymes did not increase pungent flavour or bitter aftertaste in comparison with the native bran.


Assuntos
Pão/análise , Fibras na Dieta/análise , Lactobacillus brevis/metabolismo , Saccharomycetales/metabolismo , Triticum/microbiologia , Pão/microbiologia , Culinária , Fibras na Dieta/metabolismo , Fermentação , Humanos , Tamanho da Partícula , Paladar , Triticum/química
17.
Bioresour Technol ; 149: 191-9, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24103644

RESUMO

The aim of the work was to test the hypothesis that at low water content enzyme action on biomass is enhanced when the raw material is in the form of a continuous mass instead of powder/granular form. Effects of two pre-mixing methods, blade-mixing and extrusion, on xylanase action were studied during stationary incubation of wheat bran of different particle sizes, also in comparison with incubation at high water content with continuous stirring. The use of an extruder enhanced arabinoxylan (AX) solubilisation at low water content (<54%), as compared to blade-mixing. AX solubilisation was highest in the high-water stirring treatment, but based on molecular weight, xylanase action on solubilised AX was similar as in the extrusion-aided process. Pre-mixing by extrusion enabled efficient enzyme action at low water content without the requirement for continuous mixing, probably due to the enhanced diffusion by the formation of a continuous mass in the extruder.


Assuntos
Biotecnologia/instrumentação , Biotecnologia/métodos , Fibras na Dieta/metabolismo , Endo-1,4-beta-Xilanases/metabolismo , Água/farmacologia , Bacillus subtilis/enzimologia , Etanol/química , Peso Molecular , Tamanho da Partícula , Solubilidade , Xilanos/metabolismo
18.
Food Funct ; 4(6): 972-81, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23674066

RESUMO

Rye bran contains a high amount of phenolic acids with potential health promoting effects. However, due to binding to dietary fibre, the phenolic acids are poorly absorbed in human body. We used bioprocessing with enzymes and yeast to release phenolic acids from the fibre complex and studied the effect of bioprocessing on absorption of phenolic acids in healthy humans. White wheat breads fortified with bioprocessed or native rye bran, and wholegrain rye bread and white wheat bread as controls were served to 15 subjects in a randomized order in the cross-over design. Urine was collected at the basal state and over 24 hours in four-, eight-, and twelve-hour periods and analyzed for phenolic acids and their metabolites with gas chromatography. A total of six blood samples were taken over four hours to study the effect of the bread ingestion on postprandial glucose and insulin responses. Bioprocessing of rye bran increased the proportion of free ferulic acid (FA) and soluble arabinoxylan in the bread. Ingestion of the white wheat bread fortified with bioprocessed rye bran increased (p < 0.001) urinary excretion of FA particularly during the first four hours, indicating increased absorption of FA from the small intestine. The postprandial glucose and insulin responses were similar between these breads. Bioprocessing of rye bran did not affect excretion of benzoic, phenylpropionic, and phenylacetic acid metabolites. As a conclusion, bioprocessed rye bran as compared with native rye bran increased absorption of FA from the small intestine, but did not improve postprandial glucose and insulin responses.


Assuntos
Pão/análise , Ingestão de Alimentos , Glucose/metabolismo , Hidroxibenzoatos/metabolismo , Secale/metabolismo , Adulto , Idoso , Fibras na Dieta/metabolismo , Feminino , Humanos , Insulina/metabolismo , Intestino Delgado/metabolismo , Masculino , Pessoa de Meia-Idade , Período Pós-Prandial , Secale/química
19.
J Sci Food Agric ; 93(4): 882-9, 2013 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-22865289

RESUMO

BACKGROUND: Rye and wheat bran were treated with several xylanases and endoglucanases, and the effects on physicochemical properties such as solubility, viscosity, water-holding capacity and particle size as well as the chemical composition of the soluble and insoluble fractions of the bran were studied. A large number of enzymes with well-defined activities were used. This enabled a comparison between enzymes of different origins and with different activities as well as a comparison between the effects of the enzymes on rye and wheat bran. RESULTS: The xylanases derived from Bacillus subtilis were the most effective in solubilising dietary fibre from wheat and rye bran. There was a tendency for a higher degree of degradation of the soluble or solubilised dietary fibre in rye bran than in wheat bran when treated with most of the enzymes. CONCLUSION: None of the enzymes increased the water-holding capacity of the bran or the viscosity of the aqueous phase. The content of insoluble material decreased as the dietary fibre was solubilised by the enzymes. The amount of material that may form a network to retain water in the system was thereby decreased.


Assuntos
Parede Celular/metabolismo , Fibras na Dieta/metabolismo , Enzimas/metabolismo , Secale/metabolismo , Sementes/metabolismo , Triticum/metabolismo , Água , Bacillus subtilis/enzimologia , Parede Celular/enzimologia , Dieta , Fibras na Dieta/análise , Humanos , Tamanho da Partícula , Proteínas de Plantas/metabolismo , Solubilidade , Viscosidade
20.
J Agric Food Chem ; 60(33): 8134-45, 2012 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-22731123

RESUMO

Rye bran and aleurone, wheat bran and aleurone, and oat bran and cell wall concentrate were compared in their in vitro gut fermentation patterns of individual phenolic acids and short-chain fatty acids, preceded by enzymatic in vitro digestion mimicking small intestinal events. The formation of phenolic metabolites was the most pronounced from the wheat aleurone fraction. Phenylpropionic acids, presumably derived from ferulic acid (FA), were the major phenyl metabolites formed from all bran preparations. The processed rye, wheat, and oat bran fractions contained more water-extractable dietary fiber (DF) and had smaller particle sizes and were thus more easily fermentable than the corresponding brans. Rye aleurone and bran had the highest fermentation rate and extent probably due to high fructan and water-extractable arabinoxylan content. Oat samples also had a high content of water-extractable DF, ß-glucan, but their fermentation rate was lower. Enzymatic digestion prior to in vitro colon fermentation changed the structure of oat cell walls as visualized by microscopy and increased the particle size, which is suggested to have retarded the fermentability of oat samples. Wheat bran was the most slowly fermentable among the studied samples, presumably due to the high proportion of water-unextractable DF. The in vitro digestion reduced the fructan content of wheat samples, thus also decreasing their fermentability. Among the studied short-chain fatty acids, acetate dominated the profiles. The highest and lowest production of propionate was from the oat and wheat samples, respectively. Interestingly, wheat aleurone generated similar amounts of butyrate as the rye fractions even without rapid gas production.


Assuntos
Avena/química , Colo/microbiologia , Ácidos Graxos Voláteis/análise , Fenóis/análise , Secale/química , Triticum/química , Butiratos/análise , Butiratos/metabolismo , Parede Celular/metabolismo , Colo/metabolismo , Ácidos Cumáricos/análise , Ácidos Cumáricos/metabolismo , Fibras na Dieta/administração & dosagem , Fibras na Dieta/metabolismo , Digestão , Ácidos Graxos Voláteis/metabolismo , Fezes/química , Fezes/microbiologia , Fermentação , Humanos , Intestino Delgado/metabolismo , Metagenoma , Fenóis/metabolismo , Propionatos/análise , Propionatos/metabolismo , beta-Glucanas/análise , beta-Glucanas/metabolismo
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