1,720,974 research outputs found
Effect of PEF and steam blanching treatments on the extraction yield of carotenoids from tomato wastes
No full textIntroduction. Industrial transformation of tomatoes typically include a thermophysical peeling phase of the fruits, which lead to the production of large amount of wastes, namely peels. These wastes are currently used as feed for animal or sent to landfill leading to environmental and economical problems for the industry. However, they represent a cheap and rich source of several carotenoids, particularly lycopene. Therefore, in order to pursue the concept of ―zero waste‖ or ―total use‖ of agri-food residues with increasing industrial profitability, the recovery of these high-added value compounds is a challenge. Traditionally, these compounds are recovered by extraction with solvent which is a time consuming process and requires large quantities of solvents. The aim of this work, which was carried out in the frame of the European project ―FieldFood‖, was to assess the potential of pulsed electric field (PEF) technology alone or in combination with steam blanching, to improve the recovery of carotenoids from tomato peels.
Materials and Methods. PEF treatments of whole tomato fruit were carried out at field strengths in the range 0.25-0.75 kV/cm and energy input between 0.25 and 5 kJ/kg. The evaluation of the cell disintegration index via impedance analysis was used to select optimal PEF treatment conditions. Tomato samples treated under these optimal conditions were then peeled with or without the application of a thermal treatment by steam (50–60–70°C). The achieved peels were subjected to solvent extraction in acetone for 24h, and the extracts were analysed by both spectrophotometric and HPLC analysis in order to evaluate the total carotenoids content and antioxidant activity of the extracts as well as the chemical composition of the extracts.
Results. Results showed that, for each field strength applied, the cell disintegration index increased with increasing the energy input, reaching a saturation value for an energy input of 1 kJ/kg. The application of PEF pretreatment at different field strengths and at 1 kJ/kg at room temperature, allowed to increase the total carotenoids content and antioxidant activity of the extracts up to, respectively, 2.7 and 4.2-fold those detected in the untreated samples. The application of a combined treatment (PEF + steam blanching) significantly increased the carotenoids content and the antioxidant power of the extracts, allowing to save energy with respect to a conventional steam blanching treatment. HPLC analyses revealed that PEF pre-treatment alone or in combination with steam blanching increased lycopene concentration in the extracts with respect to the untreated samples. Moreover, no evidence of selective release or degradation of individual carotenoids due to PEF application was detected.
Conclusions. Results obtained from this study demonstrate the potential of PEF as pre-treatment method to improve the efficiency of industrial processing of tomato fruits
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
Influence of high-pressure homogenization on structural properties and enzymatic hydrolysis of milk proteins
Full text linkThis study investigated the effects of HPH processing parameters on the conformational structure of bovine serum albumin (BSA) and whey protein isolate (WPI). BSA and WPI dispersions (1% w/v in phosphate buffer, pH = 7.5) were treated in a bench-scale HPH unit at different pressures (100, 150, 200 MPa) and number of passes (1, 2, 3, 5). The modifications of proteins' primary structure (carbonyl groups), secondary structure (α-helix, β-sheet, turn), tertiary and quaternary structure (free -SH groups) were analyzed together with their particle size distribution (PSD). HPH-assisted hydrolysis with trypsin and α-chymotrypsin was performed (200 MPa, 1 pass). Hydrolysis degree and molecular weight distribution of peptides were determined and compared with those of untreated protein dispersions. HPH treatments did not affect proteins' primary structure while slight modifications of secondary structure were detected. Interestingly, free - SH groups in BSA increased with increasing the pressure due to partial unfolding, while decreased in WPI, possibly due to disaggregation and compaction of native WPI aggregates. HPH pre-treatment allowed enhancing BSA hydrolysis reaction rate, while the compaction of WPI aggregates caused a reduced hydrolysis extent. In conclusion, HPH caused an appreciable modification of protein conformation and affected the degree of enzymatic hydrolysis
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
Modeling of a spray-drying process for the encapsulation of high-added value extracts from food by-products
No full textThe main goal of this research was to develop a mathematical model for a co-current spray drying-assisted encapsulation of natural extracts from grape pomace and citrus fruit peels, aiming to predict both structural features and the retention of their bioactive constituents. Model validation was performed using a laboratory scale spray dryer, analyzing the product in terms of moisture content, solids and total phenolic compounds recovery yields. The comparison between experimental and simulated results revealed that the model properly described the system. A slight effect of air inlet temperature was observed on the phenolic content of produced particles. For this reason, a kinetic law, which allows predicting the degradation of phenols was proposed and validated. These results highlighted the potential of spray-drying technology to efficiently encapsulate high-added value compounds with good preservation of their bioactive compounds, offering the possibility to decrease food waste issues while improving industry economic benefits
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