34 research outputs found

    Glycosylated Benzoxazinoids Are Degraded during Fermentation of Wheat Bran

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    Benzoxazinoids are plant secondary metabolites found in whole grain cereal foods including bread. They are bioavailable and metabolized in humans, and therefore their potential bioactivity is of interest. However, effects of food processing on their content and structure are not yet studied. This study reports effects of bioprocessing on wheat bran benzoxazinoid content. Benzoxazinoid glycosides were completely degraded during fermentation, whereas metabolites of benzoxazinoid aglycones were formed. Fermentation conditions did not affect the conversion process, as both yeast and yeast/lactic acid bacteria mediated fermentations had generally similar impacts. Likewise, enzymatic treatment of the bioprocess samples did not affect the conversion, suggesting that these compounds most likely are freely bioavailable from the grain matrix and not linked to the cell wall polymers. Additionally, the results show that benzoxazinoids undergo structural conversion during the fermentation process, resulting in several unknown compounds that contribute to the phytochemical intake and necessitate further analysis

    Effects of Disintegration on <i>in Vitro</i> Fermentation and Conversion Patterns of Wheat Aleurone in a Metabolical Colon Model

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    This work aimed to elucidate the effect of wheat aleurone integrity on its fermentability, i.e., the formation of short-chain fatty acids (SCFA) and microbial phenolic metabolites, in an <i>in vitro</i> model using human faecal microbiota as an inoculum. The structure of aleurone was modified by mechanical (dry grinding) or enzymatic (xylanase with or without feruloyl esterase) treatments in order to increase its physical accessibility and degrade its complex cell-wall network. The ground aleurone (smaller particle size) produced slightly more SCFA than the native aleurone during the first 8 h but a similar amount at 24 h (102.5 and 101 mmol/L, respectively). Similar colonic metabolism of ferulic acid (FA) was observed for native and ground aleurone. The enzymatic treatments of aleurone allowed a high solubilization of arabinoxylan (up to 82%) and a high release of FA in its conjugated and free forms (up to 87%). The enzymatic disintegration of aleurone’s structure led to a higher concentration and formation rate of the colonic metabolites of FA (especially phenylpropionic acids) but did not change significantly the formation of SCFA (81 mmol/L for enzyme treated versus 101 mmol/L for the native aleurone)

    Characteristics of the eight studies included in the meta-regression analysis on whole grain intake and occurrence of type 2 diabetes.

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    <p><sup>1</sup>Information on how whole grain intakes were reported in the original publication (as amounts of whole grain foods or of whole grain ingredients, with the unit used indicated in brackets).</p><p><sup>2</sup>Median values of lowest and highest categories of whole grain intakes, standardized in g/d of whole grain ingredients (except if indicated otherwise).</p><p>FFQ, food frequency questionnaire. HPFS, Health Professionals Follow-up Study. N, number of subjects. NA, not applicable. NHS, Nurses’ Health Study. T2D, type 2 diabetes. WG, whole grains. WHI OS: Women’s Health Initiative Observational Study. Y, years.</p><p>Characteristics of the eight studies included in the meta-regression analysis on whole grain intake and occurrence of type 2 diabetes.</p

    Systematic Review and Meta-Analysis of Human Studies to Support a Quantitative Recommendation for Whole Grain Intake in Relation to Type 2 Diabetes

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    <div><p>Background</p><p>Due to the increasing evidence of their health benefits, whole grains are recommended for consumption worldwide. Such recommendations are, however, rarely quantitative. Our aim was to perform a quantitative evaluation of the relationship between whole grain consumption and the occurrence of type 2 diabetes (T2D) to support a recommendation on the daily consumption of whole grains.</p><p>Methods and Findings</p><p>We conducted a systematic review by searching three bibliographic databases. We included human studies addressing the relationship between whole grain consumption and T2D occurrence, and providing quantitative information on daily intake of whole grains. A dose-response meta-regression analysis between whole grain intake and T2D occurrence was performed, using a hierarchical mixed least square linear regression model. Eight observational studies were included (all but one prospective), with a total of 15,573 cases of T2D among 316,051 participants. Quantitative meta-regression demonstrated a significant linear inverse relationship between whole grain intake and T2D occurrence (<i>P</i><0.0001), with an overall absolute reduction of 0.3% in the T2D rate for each additional 10 g of whole grain ingredient consumed daily. The association persisted when adjusted on sex, age, country, study design, follow up duration, and mode of report of whole grain intakes (as foods or ingredients).</p><p>Conclusions</p><p>The meta-regression model made it possible to estimate the decrease in T2D risk corresponding to various changes in whole grain intakes, and the results contribute to setting up quantitative recommendations. For instance, consuming three servings of whole grain foods (45 g of whole grain ingredients) daily would induce a 20% relative reduction in the T2D risk as compared to consuming a half serving (7.5 g of whole grain ingredients). These results should be considered for future recommendations, by considering the actual whole grain intake of the concerned populations. The systematic review protocol was published on the PROSPERO register (CRD42013006925).</p></div

    Flow diagram of study selection.

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    <p>* The list of the 210 articles selected for full text evaluation is available in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131377#pone.0131377.s006" target="_blank">S1 Table</a>, which also describes the outcome of the selection process for each article (including justification for exclusion). CVD, cardiovascular diseases; T2D, type 2 diabetes.</p

    Meta-regression analysis between whole grain intake and occurrence of type 2 diabetes.

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    <p>The dose-response meta-regression analysis between whole grain intake and occurrence of type 2 diabetes (T2D) was performed by using a hierarchical mixed least square linear regression model, with T2D rate (% of cases) as the outcome variable and whole grain intake (in g/d of whole grain ingredients) as the predictor. Each category of whole grain intake was considered as a specific statistical unit (called a “statistical series”). Eight studies were included in the meta-regression analysis. Four of the studies were subdivided into series by quintiles of whole grain consumption, two by quartiles, one by tertiles and one by six arbitrary cut-offs, resulting in 37 analyzed series in total. The size of the circles reflects the number of subjects included in each individual series. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131377#pone.0131377.s003" target="_blank">S2 Fig</a> for a semi-log representation. T2D, type 2 diabetes. WG, whole grains.</p

    Effect of Bioprocessing on the <i>In Vitro</i> Colonic Microbial Metabolism of Phenolic Acids from Rye Bran Fortified Breads

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    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 <i>in vitro</i> 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

    Occurrence of the identified lignan metabolites in the analysis.

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    <p>Three replicates from each sample type are shown; the symbols are: squares, extractable fraction (E); circles, extractable fraction in lower concentration (EL); triangles, unextractable fraction (UE); and crosses, faecal background (FB) samples. The different time points are represented with different colors: red, 0 h; green, 4 h; turquoise, 12 h; and blue, 48 h.</p

    Principal component analysis, component 1 vs. component 2.

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    <p>The different sample types are depicted as follows: E, extractable fraction; EL, extractable fraction in low concentration; UE, unextractable fraction; FB, fecal background.</p

    K-means cluster analysis of the cleaned data set (2147 markers).

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    <p>The different sample types are depicted as follows: E, extractable fraction; EL, extractable fraction in low concentration; UE, unextractable fraction; FB, fecal background, as three replicates in each sampling time (0, 4, 12, 48 h).</p
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