1,720,966 research outputs found
Biobased coatings as a solution to improve the overall performances of plastic films
No full textThe present research dealt with evaluating barrier, friction and optical properties of three different plastic films after deposition of a gelatin-based bio-coating. The composite films showed improved barrier properties against oxygen and UV radiation. Static and kinetic coefficients of friction were significantly decreased both in the film-to-film and in the film-to-metal tests, leading to a desirable value for many applications. However, bio-coated films showed lower optical performances in terms of transparency and haze. Not significant differences were observed as far as the water vapour permeability is concerned. The obtained data suggest that the lipid-protein coating tested in this study, in spite of its great potential for enhancing some characteristics of plastic packaging films, still exhibits negative aspects which necessitate further improvemen
LIGHT INDUCED CHANGES ON A MEAT MODEL SYSTEM
No full textThe appearance of fresh meat and meat products is the most important factor that influence the consumers’ selection. In fact, whereas food flavour and consistency affect subsequently purchase decisions, meat colour plays a direct role in the freshness perception and acceptability of the product at the purchase moment. The meat colour basically depends on the redox state of the myoglobin: the physiologically active species are the purple reduced pigment (deoxymyoglobin) and the oxygenate bright cherry-red form (oxymyoglobin), whereas the oxidized specie (metmyoglobin) appears brown-red. During storage, meat is characterized by a continuous dynamic conversion among the above mentioned three different myoglobin states. However the appearance of the meat surface is not affected only by the real product colour but also by the lighting conditions where it is observed. For this reason, in stores are generally used the lamp typologies able to improve the natural colour of meat. Nevertheless, often, the marketing specialist choices do not consider the potential damage induced on food by electromagnetic radiations. In fact, it is known that light causes the deterioration of lipids, vitamins, proteins and natural pigments which result in off-flavours, loss of nutrients and colour fading.
The aim of this work was to investigate the effect of different light storage conditions on the quality evolution of a meat model system.
For the experimental phase, fresh minced beef meat was homogenized with a phosphate buffer in order to obtain a final solution with a pH of 7. To avoid the microbial growth during all the experimental time, chloramphenicol was added as preservative. The obtained model system was stored in clear glass vials under two different modified atmospheres. A set of vials was closed under 60 kPa of oxygen and 40 kPa of carbon dioxide, while another set was conditioned under 3 kPa of oxygen and 97 kPa of carbon dioxide. These conditions were chosen to emulate modified atmosphere and under vacuum packaging.
During storage, the samples were exposed to constant temperature under lighting conditions produced by different light sources commonly used by retailers to illuminate meat products. In particular, a cool white lamp (Osram Dulux El Longlife 30W/840) and a nature® lamp (with high emission in the red region of the visible spectrum) were chosen. For each selected light source, the light intensity that reached the samples was recorded under real storage conditions. A series of sample was kept in the dark as reference. At different times, the samples were analysed in triplicate in order to monitor the changes occurred in the meat model system. The changes in the vial headspace gas composition, the amount of different myoglobin species and the colour (CIE L*a*b* parameters) of the model system were evaluated during time. Moreover, the lipid degradation phenomena were investigated by means of the determination of oxidation product
Biobased layers as a controlled release packaging system
No full textThe interest towards new packaging solutions has increased in the recent years. The possibility to combine plastic films and biodegradable layers in the form of thin coatings represents only one of the most recent novelty in the field. In the present work, the use of such layers for controlled release packaging purposes is describe
Evaluation of shelf life of minimally processed pineapple by using conventional and alternative methods
No full text
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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