1,720,958 research outputs found
Effect of radiofrequency heating on acrylamide formation
No full textThe formation of significant levels of the suspected carcinogen acrylamide in carbohydraterich
foods subjected to intense heating (e.g. baking and frying) has been widely reported. Although it has been demonstrated that acrylamide is formed from the reaction between
free asparagine and intermediates of the Maillard reaction, the mechanisms at the basis of
the development of this substance are still not fully understood. Results have shown that the
kinetics of acrylamide formation are affected both by intrinsic factors of the food product,
such as reducing sugar and amino acid concentration, chemical composition, water content,
pH, physical state, etc., and process parameters (heating time and temperature).
Due to the complexity of influencing factors, up today it was difficult to draw up guidelines to
reduce acrylamide formation in foods. From a technological standpoint, the preliminary and
general suggestions are relevant to the adoption of thermal treatments other than frying or
prolonged cooking, which however are responsible for a decrease in the food sensorial
acceptability.
Radiofrequency heating is a promising technology for food applications, characterised by
rapid and uniform heat distribution, large penetration depth and low energy consumption.
It is generally applied as a post-baking operation to rapidly reduce the residual moisture of
bakery products from about 6% to 3%. Although the acrylamide levels in baked products
(breads, cakes, cookies, etc.) greatly vary with formulation and processing conditions
adopted, the amounts reported are quite high, generally of the order of 200-500 ppb.
The aim of the present study was to investigate the effects of radiofrequency heating on
acrylamide formation in bakery products. Leavened cakes were obtained from a commercial
ready-to-cook formulation. Cooking was carried out by using both conventional and
radiofrequency (RF) heating. Products having different moisture levels were analysed for
acrylamide content and colour properties Results showed that acrylamide formation was
affected by the mechanism of heat transfer, i.e. conduction or dielectric heating
Effect of radiofrequency heating on acrylamide formation in bakery products
No full textThis work was addressed to study the influence of radiofrequency (RF) heating on
21 acrylamide (AA) formation in bakery products. To this purpose, leavened cakes and short dough
22 biscuits were baked to a final moisture of 3.5% and 3.0% respectively, by means of conventional
23 convection heating or different combinations of conventional and RF heating. Results showed that,
24 with respect to the baking process entirely carried out in an air-circulating oven, the RF-assisted
25 baking process, i.e. the application of RF heating in the last stages of the baking process, resulted to
26 be a promising strategy to keep low the AA levels in the bakery products. In particular, the best
27 results were obtained for products which were moved from the hot-air baking to the RF heating
28 when their residual moisture was still fairly high (around 10%). Results also suggested that, when
29 very low values of residual moisture are required, this technological intervention is more suitable to
30 thin bakery products, such as biscuits, than to thick products, such as leavened cakes, because of
31 excessive browning in the internal portion as a consequence of the RF heating
Attitudine alla trasformazione di mele di cultivar autoctone del Friuli Venezia Giulia
No full textL’obiettivo della ricerca è stato quello valutare l’attitudine alla trasformazione di mele di cultivar autoctone del Friuli Venezia Giulia. La prima parte della sperimentazione è stata dedicata alla valutazione delle caratteristiche compositive e funzionali strettamente connesse alla trasformazione della materia prima. Allo scopo sono stati considerati sia i frutti raccolti nel 2004 che quelli della raccolta 2005. Nella seconda parte del lavoro, i frutti appartenenti alle cultivar selezionate sulla base dei risultati precedenti sono stati utilizzati per produrre derivati di mela, quali puree e nettari, le cui caratteristiche qualitative sono state poste a confronto con quelle di derivati ottenuti dalla cultivar Golden Delicius.
I risultati ottenuti lasciano prefigurare la possibilità di utilizzare alcune varietà di mele autoctone per la produzione di puree e nettari con caratteristiche sensoriali comparabili se non superiori ai prodotti ottenuti da Golden Delicious. Inoltre, non è da escludere che alcune delle varietà considerate possano trovare impiego come ingredienti funzionali destinati all’ottenimento di prodotti dai forti connotati salutistici
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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