1,720,965 research outputs found
Effects of pulsed electric field-assisted osmotic dehydration and edible coating on the recovery of anthocyanins from in vitro digested berries
Full text linkBerry fruits, such as strawberries and blueberries, are rich sources of anthocyanins. Several studies have been made on the impact of non-thermal treatments on safety, shelf-life and nutritional characteristics of such products, but the effects of these processes on anthocyanin stability during digestion in the gastrointestinal tract are still not completely clear. The aim of this study was to assess the recovery of anthocyanins after simulated gastrointestinal digestion of (1) strawberry samples, pre-treated with pulsed electric field (PEF) at 100 or 200 V·cm−1, prior to osmotic dehydration (OD), and (2) blueberry samples coated with chitosan and procyanidin. After digestion, a significantly higher content of cyanidin-3-O-glucoside and malvidin-3-O-glucoside was quantified by LC-MS/MS in processed strawberry and blueberry samples, compared with the controls. The highest recovery of cyanidin-3-O-glucoside was detected in digested strawberry samples osmotically dehydrated with trehalose. The recovery of malvidin-3-O-glucoside was highest in digested blueberries coated with chitosan and stored for 14 days, compared with untreated samples or samples coated with chitosan and procyanidin. Our study shows the potential of mild PEF treatments combined with OD, or the use of edible coating, to obtain shelf-stable products without substantially affecting the composition or the stability of anthocyanins during digestion in the upper gastrointestinal tract
Phytate degradation in wheat buckwheat, soy, and rice flours by lactobacilli and yeast isolated from African and Asian traditional fermented food
No full textPhytic acid (myo-inositol 1,2,3,4,5,6-hexakisphosphate) is a phosphorus reservoir found especially in cereals, legumes, and oilseeds. This compound forms complexes with essential minerals such as K, Mg, P, Ca, Fe, Zn, and Mn, thus reducing their bioavailability. Therefore, due to its negative impact on intestinal mineral absorption, phytic acid is considered an antinutritional substance, as it can modify functional characteristics in food proteins. In seeds, the aleurone layer contains approximately 90% of the grain's phytic acid, with the germ holding about 10%.
Consequently, flours, especially those from whole grains, are rich in phytic acid. Therefore, increasing the use of bran and whole wheat flour in food formulations may compromise the nutritional quality of end products by limiting mineral bioavailability. Microbial fermentation has been described as a strategy to reduce the adverse effects of phytic acid in food products. The present work aimed to thoroughly investigate the impact of different yeasts and lactic acid bacteria, isolated from Asian and African traditional fermented foods, on different flours (wheat, buckwheat, rye, and soy flours) and doughs prepared with selected cereal meals on the levels of phytate during fermentation and breadmaking. Eleven yeasts belonging to Pichia kudriavzevii, Saccharomyces cerevisiae,
Pichia fermentans, and Kluyveromyces marxianus and two lactobacilli belonging to Lactiplantibacillus plantarum and Lacticaseibacillus paracasei have been selected. The comparison of selected yeasts and lactobacilli in
the degradation of phytic acid with different flours as substrates (wheat, buckwheat, soy, and rice) showed that the
degradation ranged from 16 to 77%. The best-performing strain resulted in P. kudriavzevii TY1322 with 77% of phytic acid degradation. The degradation of phytate for bread production using single yeast was 52.06% ± 4.25, while when a mixed inoculum yeast-lactobacilli was used, the degradation improved up to 60,02% ± 0.21. Lactobacilli can achieve a strong phytic acid degradation both by lowering pH and providing more suitable
pH conditions for phytate degradation by endogenous phytases and by a direct source of microbial phytases.
Since the potential benefits of bread incorporating various grains (e.g., soy, buckwheat, and rye) are increasingly
evident, this research could have an important implication for human health
Folate production in bifidobacteria from omnivores, herbivores and carnivores
No full textFolates are water-soluble B-group vitamin that are cofactors in many metabolic pathways such as DNA synthesis and methylation pathways. Humans cannot synthesize folate and its low status has been implicated in a wide variety of disorders. Naturally occurring food folates occur in abundance in leafy green vegetables, yeast extracts,
citrus fruit, liver and kidney. Folate could derived, other than from diet, from indigenous bacteria of the microbiota which posses the ability of de novo folate production. Intestinal bacteria such as bifidobacteria can produce this cofactor by themselves from simple precursors; howewer some bifidobacteria are auxotrophic and have a strict growth requirement for folic acid. The study of folate metabolism in bifidobacteria isolated from different animals, such as omnivorous,
herbivorous and carnivorous, could advances the knowledge of host-interaction in relation to endogenous folate production for possible microbiota modulation. We aimed to investigate the production of folate by bifidobacteria isolated from animals differing in
diet in order to assess the potential indigenous contribute of folate availability provided by the microbiota.We aimed to investigate the production of folate by bifidobacteria isolated from animals differing in
diet in order to assess the potential indigenous contribute of folate availability provided by the microbiota
The potential of bifidobacteria as a source of natural folate
No full textAims: Nineteen strains of bifidobacteria were screened for main folate forms composition in synthetic folate free and complex folate-containing media.
Methods and Results: HPLC was used to analyze deconjugated folates extracted from bacterial biomass. Most strains had a total folate content above 4000 μg/100g DM. The highest value of 9295 μg/100g DM was found in B. catenulatum ATCC 27539 and the lowest in B. animalis subsp. animalis ATCC 25527 containing 220 μg/100g DM. 10 strains grew in synthetic folate free medium (FFM), showing folate autotrophy and suggesting folate auxotrophy of the remaining nine. In the autotrophic strains, a consistently higher folate level was found in FFM as compared to a more complex folate-containing medium, suggesting reduced requirements for folates in the presence of growth factors otherwise requiring folates for synthesis. The contents of
total folate, 5-CH3-H4folate and H4folate were strain dependent. 5-CH3-H4folate dominated in most strains.
Conclusions: Our results show that bifidobacteria folate content and composition is dynamic, strain-specific and depends on medium. Suitable selection of the growth conditions can result in high levels of folate per cell unit biomass.
Significance and Impact of Study: This suggests that certain bifidobacteria may contribute to the folate intake; either directly in foods, such as fermented dairy products, or in the intestine as folate-trophic probiotics or part of the natural microbiota
FOLATE PRODUCTION IN BIFIDOBACTERIA FROM INFANT AND ADULT HUMANS
No full textFolates – the natural chemically reduced forms of folic acid (vitamin B9) - are cofactors in essential
metabolic pathways such as DNA synthesis and methylation pathways. Humans cannot synthesize folate and depend on
intake both from the diet (green vegetables, cereals, rice, milk, fermented milk products, etc.) and from indigenous folate
synthesizing bacteria of the intestinal microbiota. Low folate levels increase the risk for neural tube defects and may
increase the risk for e.g. certain cancer forms, cardiovascular disease and Alzheimer’s.
Screening for folate production of the bifidobacteria isolates from human adult and infant (1-6 month
old) was performed. Strains typical of infants, such as Bifidobacterium longum subsp. infantis and B. breve, and of adults (
B. adolescentis) were selected for characterization. The aim of the present work was to investigate bifidobacteria from
human host of different age with different feeding habits in order to establish a possible correlation between diet and the
folate production. Folate is present in many different forms in humans. The detectable forms studied in the present work
are 5-CH3-H4, H4 and total folate content. Bifidobacteria strains were cultivated in folate free synthetic media. Validated
HPLC method was used to analyze deconjugated folates extracted from bacterial biomass
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
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