1,720,987 research outputs found
Characterization of the medium infrared spectra of polyphenols of red and white wines by integrating FT IR and UV–Vis spectral data
No full textInfrared spectroscopy is widely applied in the wine sector. The medium infrared (MIR) spectral region between 1800 and 900 cm-1 is very informative for polyphenols. Aim of this work was to perform an in-depth analysis of this spectral region of polyphenolic wine extracts. To this goal evolution of the polyphenolic fractions of white (Vermentino) and red (Cannonau) typical Sardinian wines was studied during wine-making. Wine polyphenolic extracts, obtained by solid phase extraction, were analyzed by Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) and UV–Vis spectroscopy. Spectral data from the two techniques were integrated and results depicted as Heat Map of the correlation coefficient values allowing a more accurate characterization of the MIR fingerprint region. For Cannonau, correlations between absorptions in the 420–650 and 380 nm visible spectral ranges allowed assignment of MIR peaks to anthocyanins (1016 and 1198 cm-1) and flavonols (1159 and 1277 cm-1), respectively. In Vermentino we identified MIR bands due to non-flavonols and others arising from flavonols (1376 and 1407 cm-1), present in this white wine where vinification allows short time contact with grape skins. During time, intensities of MIR bands at lower frequencies assigned to the sugar moiety of glycosylated phenols decreased in both wines
Seasonal Variations of Milk Composition of Sarda and Saanen Dairy Goats
Full text linkTraditionally, in Mediterranean areas the goat population was composed of autochthonous breeds with strong milk production seasonality. In the last decades, high productive alpine breeds were introduced together with more widespread out-of-season milk production practices. This study is a large-scale survey on the seasonal variations of the main compositional characteristics of goat milk obtained from Sarda and Saanen breeds reared on the Mediterranean island of Sardinia (Italy). Analysis of data indicated that milk from the Sarda breed was significantly richer, at p < 0.001, in protein, fat, and lactose, and had a lower urea mean content than Saanen. Throughout the year, fluctuations of mean contents of the milk parameters were similar for the two groups of goats, indicating that, besides genetic intrinsic differences, climate and herbage growth influenced the Sarda as well as the Saanen goats. During the summer, milk from Saanen showed a marked drop in fat and protein contents, with 21% of samples showing a fat-to-protein ratio <1. No significant differences were found for the somatic cell count; however, the Sarda breed showed a higher bacterial count, suggesting improper milk handling and/or storage equipment more frequently encountered in extensive and semi-extensive farm systems
NMR metabolite profiles of dairy: A review
No full textNuclear magnetic resonance (NMR) spectroscopy, which is one of the most powerful “omics” analytical platforms, has been broadly adopted recently in foodomics. 1H NMR has been applied to the study of the metabolite profile of dairy products throughout the supply chain, in relation to different aspects such as animal health, milk quality, geographical origin and cheese ripening process. This review reports and discusses the literature on the topic, also collecting the identified metabolites in a descriptive table and depicting them in a Venn diagram for both milk and cheese; moreover, experimental details of the reviewed papers have been reported. The present review provides an exhaustive state-of-the-art in the field of dairy products, addressing both NMR experts and non-experts to the still unexplored potential applications of NMR in dairy characterisation, and in general in foodomics
NMR lipid profile of milk from alpine goats with supplemented hempseed and linseed diets
Full text linkThe supplementation of goat diets with natural products to obtain milk with nutraceutical components is a common practice. In these last years, the influence of supplementation of specifically designed diets has been studied with different analytical tools in order to explore possible beneficial effects in human consumption of animal milk and milk-derived products. In this study, the lipid fraction of milk from Alpine goats undergoing different dietary regimens was studied by 1H-NMR spectroscopy. Alpine goats were fed with linseed or hempseed supplements, and after 14 weeks of treatment, milk was collected and analyzed. Results showed that feeding diets supplemented with seeds positively affected the fatty acid composition with a pronounced increase in unsaturated fatty acids for both diets compared to a control diet. Specifically, linolenic acid content was more than doubled for linseed diet compared with the hempseed and control groups, while linoleic acid greatly increased only upon hempseed supplementation. However, a number of conjugated linoleic acid (CLA) isomers and higher levels of fatty acids with trans configuration were found in supplemented diets, particularly in the linseed diet
GC-MS metabolomics comparison of yoghurts from sheep's and goats' milk
No full textIn this study, the polar metabolite profile of commercial yoghurt samples produced in Sardinia (Italy)from milk of local sheep and goats was studied by GC-MS and multivariate statistical data analysis (MVA). Milks underwent the same manufacturing procedures and yoghurts were analysed one day post-manufacture. Results of discriminant analysis indicated that the two yoghurt types had very different metabolite profiles, with different levels of health promoting compounds. Goats' milk yoghurt was richer in free amino acids, γ-aminobutyric acid, pyroglutamic acid and β-phenyllactic acid when compared with yoghurt produced with sheep's milk. Sheep's milk yoghurt was characterised by higher levels of myo-inositol, N-acetylgalactosamine and N-acetylglucosamine. Comparing yoghurt metabolites with those of the original milk, it was found that goats' milk underwent stronger metabolite changes after inoculum. The comparison between the two yoghurt types gave us a deeper insight on the effects of manufacture on different milks
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
Cytochrome c used as a model system to probe the structural properties of benthic mucilage
No full textBenthic mucilage, whether native or artificially fragmented to microscopic dimensions by ultrasonic treatment, was mixed with cytochrome c, which was used as a 12000 Da polycationic model compound. Cytochrome c binding profiles proved to depend on the aggregation state of the mucilage. The native mucus matrix binds cytochrome c quasi hyperbolically with an apparent affinity constant K = 1 x 106 M-1. As shown by chemical modification of both the mucilage and cytochrome c, the binding expression is dependent on the availability of both the positive charges on the cytochrome c surface and the negative charges within the mucus matrix. The extent of binding is sensitive to the ionic strength of the medium. The ultrasonic-stabilized mucus fragments display a peculiar binding profile, with an apparent low affinity, abruptly entering into a high affinity binding region. The results suggest that, depending on the mucus to polycation ratio, a polymeric reticulus builds up. This reticulus can accommodate molecules of at least 12000 Da molecular weight. The results are also discussed with respect to biological implications
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
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