1,720,956 research outputs found
Qualità della nocciola: confronto del potere antiossidante di differenti cultivar
No full textIl valore nutrizionale e salutistico delle nocciole è legato a numerose componenti: profilo della frazione lipidica, contenuto di fibre e fitosteroli e presenza di sostanze antiossidanti, come tocoferoli e composti fenolici. Questi ultimi possono contribuire, in sinergia con la vitamina E, a proteggere le LDL dai danni ossidativi, riducendo i rischi di malattie cardiovascolari; nel seme tal quale o trasformato, favoriscono la stabilità durante la conservazione. La buona dotazione di composti fenolici nella nocciola è stata accertata da alcune ricerche. Diversi fattori, genetici, ambientali e colturali, determinano variabilità del contenuto di queste componenti; in particolare, l’effetto della cultivar ha certamente un ruolo di rilievo e merita di essere indagato per meglio caratterizzare la qualità delle nocciole, favorendone il consumo attraverso una concreta attività promozionale.La ricerca, che si inserisce nel progetto MIPAF ‘Studio e ottimizzazione della Filiera corilicola dell’area Cimino-Sabatina’, è stata quindi finalizzata alla determinazione del contenuto di polifenoli totali e della capacità antiossidante totale (CAT) e delle frazioni lipofila ed idrofila nel seme di 24 cultivar di nocciolo di diversa origine geografica, coltivate nella collezione di Vico Matrino (VT). Le analisi sono state effettuate su campioni raccolti nel settembre 2004; i metodi analitici utilizzati sono stati il TEAC (Trolox Equivalent Antioxidant Capacity), per il potere antiossidante, ed il Folin Ciocolteau, per i polifenoli totali, espressi come equivalenti di acido gallico (GAE). Alcune cultivar si sono differenziate nettamente per la capacità antiossidante totale del seme. La più alta CAT è stata rilevata in Tonda Gentile delle Langhe, con valori di 0,45 mmol di TE su 100 g di peso del seme fresco (5% di umidità), mentre Tonda di Giffoni ha evidenziato la minore CAT, con valori pari a 0,15 mmol. La CAT media delle 24 cultivar era di 0,27 mmol di TE. Il potere antiossidante presentava un’ampia variabilità tra cultivar per la frazione idrofila, con valori compresi tra 0,02 mmol di TE su 100 g in Gunselebert, e 0,29 mmol in Tonda Gentile delle Langhe. Per la componente lipofila la capacità antiossidante era compresa tra 0,2 e 0,08 mmol e non differiva significativamente tra le cultivar. Il contenuto medio di polifenoli delle cultivar analizzate è risultato di 2,71 mg GAE/g, con valori massimi in S. Giovanni (5,87) e minimi in Santa Maria del Gesù (0,98).All’analisi della regressione, il contenuto di polifenoli non è risultato significativamente correlato con la CA idrofila della nocciola, verosimilmente per la variabilità della composizione fenolica, costituita da classi di fenoli caratterizzati da differente attività antiossidante. Tuttavia, per diverse cultivar, come Camponica e Daviana, è stato rilevato una CA elevata in corrispondenza di alti contenuti di polifenoli totali. Nel complesso, dai risultati ottenuti è possibile affermare che la nocciola è dotata di una buona capacità antiossidante totale, mediamente superiore a 3 μmol di TE per g di nocciola. Questo valore, riferito comunque al peso fresco, è inferiore a quello osservato per alcuni piccoli frutti (mirtillo, lampone, fragola), ma pari o superiore a quello della frutta fresca di uso comune
Nut quality and sensory evaluation of hazelnut cultivars
No full textIn order to evaluate the influence of chemical composition on nut quality and to characterize the sensory attributes, seven cultivars grown in a germplasm collection established in Viterbo, were analysed. Nut traits and quantitative and qualitative determination of sugars, organic acids, and lipids were carried out. Total polyphenols in the kernel were measured. The sensory profile was examined on roasted kernel. The information relating to secondary components, such as soluble sugars and organic acids was useful for discriminating among cultivars. Fatty acid composition and level of polyphenols varied among cultivars thus giving a different contribution to the potential nutritional and dietetic value of the nuts. Sensory analysis was able to reveal varietal differences for attributes related to taste and flavour. Sweet, aromatic and tasty nuts were the most appreciated by the panelists, whereas oiliness was negatively related to global preference. A positive relationship between sweetness scores and sugar concentration was observed. Due to the effect of these compounds on sensory attributes perceivable by consumers, their concentration and the varietal differences can be considered primary determinants of nut quality and should be valued when planning the cultivar choice
Nut and kernel traits and chemical composition of hazelnut (Corylus avellana L.) cultivars
No full textNut and kernel traits and chemical composition of 24 Italian and foreign hazelnut cultivars were analysed in order to study the effect of genotype and environment on nut quality.Quantitative and qualitative determinations of sugars, organic acids and lipids revealed good nutritional and health potential of the nuts with several differences among cultivars and years. The total content of oil and sugars ranged respectively from 563.69 to 656.36 g kg-1 dry weight (DW) and 39.80 to 59.51 g kg-1 DW. Fatty acid profile, sugar and total phenolic content varied in the years. Significantly higher palmitic acid concentration (6.18%) was found in the hot summer 2003; lower saturated fatty acid concentration and higher unsaturated/saturated acid ratio (11.27) were observed in the cooler year. These differences among years were highlighted by discriminant analysi
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
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