1,721,009 research outputs found
Organic acids profile in tomato juice by HPLC with UV detection
No full textA simple method was developed to determine 10 organic acids simultaneously
in tomato products using reverse-phase high performance liquid chromatography
(HPLC) column with the diode array detector set at 210 nm. After
centrifugation and filtration, the samples were passed through to an anion
exchange resin and the organic acids were released using 0.1 N HCl. The
chromatographic separation was achieved with isocratic analysis in a 20-min
run. The method was reliable and sensitive. The coefficient of determination of
the standard calibration curve is 0.9925 r2 0.9999 and the limit of detection
ranged from 0.08 to 6.00 mg/kg for trans-aconitic acid and acetic acid,
respectively. The limit of quantification ranged from 0.19 to 15.18 mg/kg for
trans-aconitic and acetic acid, respectively. To establish the efficiency of the
anion resin the procedure was applied to a standard solution of a mixture of
organic acids. The organic acids recovery ranged from 87.0% 1.9 for citramalic
acid to 109.9% 5.2 for fumaric acid
Detector elettrochimico ECD (Coularray®): applicazione nel settore enologico per la determinazione di sostanze antiossidanti
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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
Accelerated shelf-life model of gluten-free rusks by using oxidation indices
No full textThe demand for gluten-free products has been growing over the last few years as is the need to improve their quality. The objective of this research was to develop a shelf life prediction model of gluten-free rusks. To this aim, a kinetic study of the primary and secondary oxidative process was run and the kinetic parameters (rate constant, activation energy, and temperature quotient) were calculated. The protective effect of the antioxidant included in the recipe was also evaluated, and the prediction model was applied to predict the shelf life of an experimental batch of gluten-free rusks with a lower content of antioxidant. The results highlighted (i) the reliability of the prediction model and (ii) the effectiveness of the antioxidant in reducing the rate of primary oxidation. Moreover, (iii) a possible hexanal threshold (lower than 121 μg/kg), correlated with rancid perception in gluten-free rusks, was also speculated
Liposoluble vitamin extraction by supercritical carbon dioxide. a) In meat and dairy products
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