1,720,964 research outputs found
Production of stable emulsions using beta-glucans extracted from Pleurotus ostreatus to encapsulate oxidisable compounds
No full textThe basidiomycete Pleurotus ostreatus is a sustainable food source known to be rich in beta-glucans, functional compounds in mushrooms recognised for their numerous health, nutraceutical and physicochemical properties. The aim of the present study was to extract beta-glucans from P. ostreatus powder and to study the feasibility of using the extract to prepare oil-in-water emulsions formulated for the encapsulation of lipophilic antioxidants by spray drying e.g. with an oil droplet size about 2mm, a dry matter content of 40% w/w and with a physical stability of at least 2 h. Hot-water soluble beta-glucans fraction was extracted from P. ostreatus powder following a method adapted from Synytsya et al., (2009). Emulsions were prepared by rotor-stator homogenisation using maltodextrin DE12 as wall material, beta-glucans extract as emulsifier and commercial sunflower oil as a model for lipophilic active compounds. The emulsion stability was estimated from the evolution over time of the oil droplet size distribution measured by laser light diffraction. Extracts containing up to 27% w/w watersoluble beta-glucans were produced. Physically stable mono-modal emulsions were
obtained when MD/beta-glucans weight ratio was lower than about 500 to avoid depletion and beta-glucans/oil weight ratio was more than 0.014 to stabilize oil droplets. The usage of emulsifiers made-up by polymeric constituents with inherent bioactivity, such as mushroom beta-glucans, could be a sustainable and healthy alternative to common emulsifiers
Influence of antioxidant location on the protection of oil encapsulated in powder
Full text linkEncapsulation of Poly Unsaturated Fatty Acids (PUFAs) in solid matrix, by providing a physical barrier, is used to prevent or delay their degradation; and the use of antioxidant is expected to enhance PUFAs oxidative stability. In liquid emulsions, the effectiveness of antioxidants is known to depend on their distribution between the oil and aqueous phase. In this study, the impact of the lipophilic or hydrophilic character of phenolic antioxidants on the oxidative stability of encapsulated PUFAs was investigated following the evolution of conjugated dienes and antioxidant residual content during accelerated ageing test (50°C, 60% RH). Dry emulsions containing 10%wt stripped sunflower oil (60% PUFAs), 89.7%wt maltodextrin DE12 (wall material) and 0.3%wt Tween®20 (surfactant) were produced by spray drying. Some were enriched with alpha-tocopherol (lipophilic - 500 ppm in oil) or chlorogenic acid (hydrophilic, 1000 ppm in maltodextrin), two scavengers of lipid radicals implied in oxidation.Antioxidants improved the oxidative stability of encapsulated oil. With chlorogenic acid, oil oxidation occurred after a two days lag phase whilst for alpha-tocopherol, no lag phase was observed but the oxidation rate was smaller than in control and chlorogenic acid powders during the ten first days of ageing (Fig, 1a). The residual concentration of chlorogenic acid deceased rapidly during the first two days and then remained constant whilst the concentration of alphatocopherol decreased regularly ensuring oil protection until it has been totally consumed after ten days (Fig.1b). The better oil protection provided by alpha-tocopherol during the first ten days of storage was attributed to the different location of both antioxidants within the macro-domains of the dry emulsion. Alpha-tocopherol, in oil droplets, was directly in contact with the oil to protect whilst for chlorogenic acid, entrapped in the solid matrix, only the fraction in contact with the oil droplets brought protection and 60% of initial chlorogenic acid remained preserved in the matrix
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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