1,721,208 research outputs found
Effect of different extraction solvents on carotenoids recovery in tomato products
No full textFoodOmics: Food to Life. The scientific forum where academic and industrial scientists involved in food and nutrition research will discuss about the most recent advances in the “omics” approach
Buckwheat honeys: Screening of composition and properties
No full textThe quality of 10 buckwheat honeys, collected from Italian and est European beekeepers declaring to produce
monofloral honey, were evaluated by means of their pollen, physicochemical, phenolic and volatile
composition data. The results of the traditional analyses and in particular electrical conductivity, optical
rotation, pH and sugar composition revealed some poorly pure samples that could not fit in the buckwheat
tipology. Honey volatiles, analysed by solid phase microextraction (SPME) and gas chromatography–
mass-spectrometry (GC/MS), showed more than 100 volatile compounds, most of them present in
all honey samples but with quantitative variation. Besides many furfural derivates, 3-methylbutanoic
acid was the main volatile compound found in most of honeys. Also the presence of 2- and 3-methylbutanal
and pheynalcetaldehyde confirmed the typical buckwheat aroma of some studied samples, corroborating
physicochemical data. The HPLC phenolic profile was similar across the samples and phydroxybenzoic
and p-coumaric acids proved to be the main components
Study of enriched olive oil with high nutritional and biological value: olives and hazelnuts co-pressing
No full textOlive oil is the main source of fat in the Mediterranean diet and its consumption has been related to a low incidence of coronary heart disease and certain cancers. These protective effects are attributed mainly to two fundamental components of oilve oil: monounsaturated fatty acids (MUFA) and antioxidant substances.
Also nuts are included in healthy diets and, among them, hazelnuts (Corylus avellana L.) are very interesting as a source of nutritious food with a high content of functional lipids. Hazelnut’s benefits are mainly related to its fatty acid composition, rich in MUFA, tryacylglycerol profile, tocopherols and other bioactive compounds like phytorterol and polyphenols.
On the basis of these considerations the aim of this work was to investigate the quality of an olive oil obtained by a co-pressing of olives and hazelnuts. In particular, three different samples were studied: olive oil obtained crushing 0% (O), 5% (O5N) and 10% (O10N) of hazelnuts.
Classical methods based on gas-chromatography (GC) and high-performance liquid chromatography (HPLC) have been used for fatty acid, tryacylglycerol, phytosterol and tocopherol characterization. No significant differences were noticed among the three olive oils, except for phytosterols. The small components 7-stigmastenol and 7-avenasterol, charatcteristic of the hazelnut sterol profile, were found to be present in higher amount in samples O5N and O10N than the simple olive oil
Besides, the samples were also analysed by FT-MIR spectroscopy in the frequency range 1500 -900 cm-1. The FT-MIR spectra were processed by using principal component analysis (PCA) and partial least squares regression (PLS). The first one was used to discriminate the sample oils with different content ofhazelnut, instead the second one was employed to predict tocopherol and tryacylglycerol content (R2 up to 0.87 in cross verification
Comparison of the lipid content, fatty acid profile and sterol composition in local Italian and commercial royal jelly samples
No full textRoyal jelly (RJ) is a beehive product that has gained a significant scientific and commercial interest due to its healthy properties. In the present study, lipid content, fatty acid profile and phytosterol amount were determined in eight local and four commercial pure RJ samples. A mixture of diethyl ether/isopropanol 50/1 (v/v) was chosen to extract fat matter from RJ. Lipid amounts ranged from 2.3 and 7.2 % and from 2.0 to 3.2 % of the fresh product in local and commercial RJ, respectively. Fourteen fatty acids and three phytosterols were identified. About 70 % of the total fatty acids consisted of (E)-10-hydroxy-2-decenoic and 10-hydroxydecanoic acid. No significant difference was observed between local and commercial samples in regards to the relative amount of individual fatty acids. Sterols were in the range 179-701 and 329-1,097 mg kg-1 of fat in local and commercial RJ, respectively. A significant difference (p ≤ 0.05) was observed within RJ types in regards to the 24-methylenecholesterol fraction, amounting to 77 and 67 % of identified sterols in local and commercial products, respectively. © 2014 AOCS
Influence of postharvest drying process on walnut bioactive compounds
No full textWalnuts (Juglans regia L.) are an important component of the Mediterranean diet and they have been long consumed as a highly nutritious food in many parts of the world. Walnut consumption was associated with lower BMI, waist circumference, systolic blood pressure and higher high density lipoprotein-cholesterol, compared with no consumption. These effects have been attributed to different bioactive compounds that have been contained in these nuts.
However, walnuts are consumed after a drying process; because of that the aim of this work is to determine the influence of drying on some bioactive compounds. Three different walnut samples were obtained from a local company located in Forli (Italy). The fresh samples were drying as reported in the regional advisories for Integrated Crop Management. Fatty acids, sterols, tocopherols and phenolic compounds have been analyzed in fresh and dried walnut samples.
The major fatty acids found in walnuts are oleic (18:1), linoleic (18:2), and linolenic (18:3) acids; no statistical differences were noticed among fresh and dried samples. Four tocols were also identified. Gamma-tocopherol was the principal tocol determined in walnut samples; drying process increased the tocols content. GC-MS analysis permitted the identification of six sterols. As expected, sitosterol represented the first sterol compound in all samples. Drying process negatively affected the sterols content; in fact total sterol losses ranged from 6 to 34 %. Finally, walnut phenolic compounds were determined by HPLC-MS. A total of 45 phenolic compounds were identified and quantified. As expected, gallic and ellagic derivatives represented 88.6-90.2 % of total phenolic compounds. As reported for sterols, phenolic compounds content decreased (19-44%) from fresh to dried walnut samples
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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