1,721,013 research outputs found
Study of the nutritional changes and evolution of microbiota during sourdoughlike fermentation of wheat bran
No full textNUTRITIONAL ENHANCEMENT OF WHEAT MILLING BY-PRODUCTS: CHEMICAL CHANGES AND EVOLUTION OF MICROBIOTA DURING SOURDOUGHLIKE FERMENTATION OF BRAN
Full text linkSeveral epidemiological studies indicate that high whole grains diets work as protective factors against chronic diseases, such as metabolic syndrome, cardiovascular diseases (CVD), and gastrointestinal cancer. These effects are likely related, at least in part, to their high content of fiber and bioactive compounds, with antioxidants and anti-carcinogenic properties, mainly present in bran and germ of cereal grains. Removal of these fractions during milling to improve shelf-life of the flour results in severe depletion of fiber and bioactive compounds. The loss of about 58% of fiber, 83% of Mg, 61% of folate and 79% of vitamin E has been shown in comparing the content of important nutrients in wholemeal flour and white flour. The aleurone layer (the outermost layer of the endosperm) has been shown to contain many of these functional compounds, but it is partially eliminated in wheat flour milling as a by-product mostly used for the animal feed.
The increasing demand for functional foods and the possibility to take advantage of agro-industrial by-products have attracted great interest in using bran-enriched products. This should lead to a greater value for wheat industries, reducing their environmental impact and getting an economic return. The main reason behind the low utilization rate of wheat bran in baking industry is the gritty texture, bitter and pungent flavour and coarse mouthfeel of bread caused by the bran. However, the fermentation of cereal bran, with yeasts and lactic acid bacteria or with specific enzymes, has been shown to be an interesting pre-treatment to improve technological, sensorial and nutritional properties of bran-enriched products, as well as to degrade anti-nutritive factors, such as phytic acid, in order to increase mineral bioavailability.
This study was aimed to increase the amount of bran’s bioactive compounds, such as soluble fiber, water-extractable arabinoxylans, free ferulic acid, through a fermentation process, in order to use the fermented bran as a potential functional ingredient.
Wheat bran sourdoughlike fermentation processes were conducted through continuous propagation by back-slopping of fermented bran until a stable microbiota was established, reaching high counts of lactic acid bacteria and yeasts. At each refreshment step, bacterial strains were isolated, clustered, molecularly analysed by Randomly Amplified Polymorphic DNA PCR and identified at the species level by 16S rRNA gene sequencing. Leuconostoc mesenteroides, Lactobacillus brevis, Lactobacillus curvatus, Lactobacillus sakei, Lactobacillus plantarum, Pediococcus pentosaceus and Pichia fermentans were dominating the stable sourdough ecosystem.
After fermentation, levels of soluble fiber increased (+ 30%), water-extractable arabinoxylans and free ferulic acid were respectively fourfold and tenfold higher than in raw bran, results probably related to endogenous and microbial enzymatic activities, while phytic acid was completely degraded.
On the basis of the interesting nutritional results, some isolated stains were also characterized in order to select potential starter cultures. The lactic acid bacteria (LAB) were characterized by their bran fermentation capacity, antifungal activity, carbohydrate metabolism, exopolisaccharides production, as well as their antibiotic resistance profiles. The LAB and the yeast were also tested for their potential xylan- and phytate-degrading activities. Moreover, common probiotic properties of the bacterial strains, such as acid and bile tolerance, anti-listeria activity and adhesion to the human intestinal epithelial cells Caco-2 cells were examined. Results suggest that strains belonged to L. plantarum and P. pentosaceus species could have interesting technological applications, due to their antifungal activity and EPS production. Some of these strains also exhibited phytate degrading activity and thus they could be exploited to improve mineral bioavailability of fermented products. Moreover, L. curvatus (CE 83), L. brevis (CE 85), and P. pentosaceus (CE 65), seemed to be suitable candidates to be used as probiotics.
In conclusion, the current study supports the hypothesis that fermentation process is an efficient means to increase the amount of bioactive compounds of wheat bran. The characterization of the bacteria involved in bran sourdoughlike fermentation was the first step toward selecting starter cultures, according to their metabolic and enzymatic activities, in order to conduct “tailored” bran fermentation process and improve technological and nutritional properties of bran-enriched products. The present study has shown that investigated properties of the lactic acid bacteria tested are highly strain-specific. In this sense, the study of microbial diversity represents an opportunity for advances in biotechnology and the possibility of mixing strains with different properties and activities could be an interesting approach to obtain fermented products with improved qualities
Phytate/calcium molar ratio does not predict accessibility of calcium in ready-to-eat dishes
No full textBACKGROUND: Phytic acid (PA), a naturally occurring compound of plant food, is generally considered to affect mineral
bioavailability. The aim of this study was to investigate the reliability of the PA/calcium molar ratio as a predictive factor of
calcium accessibility in composed dishes and their ingredients.
RESULTS: Dishes were chosen whose ingredients were rich in Ca (milk or cheese) or in PA (whole-wheat cereals) in order to
consider a range of PA/Ca ratios (from 0 to 2.4) and measure Ca solubility using an in vitro approach. The amounts of soluble
Ca in composed dishes were consistent with the sum of soluble Ca from ingredients (three out of five meals) or higher. Among
whole-wheat products, bread showed higher Ca accessibility (71%, PA/Ca=1.1) than biscuits (23%, PA/Ca=0.9) and pasta (15%,
PA/Ca=1.5), and among Ca-rich ingredients, semi-skimmed milk displayed higher Ca accessibility (64%) than sliced cheese
(50%) and Parmesan (38%). No significant correlation between the PA/Ca ratio and Ca accessibility was found (P = 0.077).
CONCLUSION: The reliability of the PA/Ca ratio for predicting the availability of calcium in composed dishes is unsatisfactory;
data emphasized the importance of the overall food matrix influence onmineral accessibility
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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