1,721,045 research outputs found
Convenient synthesis of deuterium labelled sesquiterpenes
No full textSesquiterpenes are an important class of molecules, with roles ranging from pollination and signalling to defense mechanisms. Despite their apparent importance, the limited number of commercial standards has hindered their study and precise quantification. Herein, we report the syntheses of fourteen labelled sesquiterpenes with a high level of deuterium incorporation (>95%) for applications in MS-based studies
Oenological tannins as a source of thiol precursors
No full textOenological tannins are a widely used adjuvant in winemaking. They can help stabilising colour, stringency and
flavour. European regulation currently allows tannins produced form vegetable origins in winemaking.
Previous researches have already highlighted the contribution that tannins can give to flavour [1] and aroma [2]
of wine.
Among the aroma classes identified and investigated in wine, varietal thiols (i.e. 3-mercaptohexan-1-ol, 3-
mercaptohexyl acetate and 4-mercapto-4-methylpentan-2-one) are particularly important for their extremely low
sensory threshold and highly appreciated aroma descriptors [3].
In this communication we are presenting the first identification of two known thiol precursors (S-3-
glutathionylhexan-1-ol and S-3-cysteinylhexan-1-ol) in oenological tannins [4] and the impact of controlled
addition of this adjuvant on free thiols in the final wines [5].
This evidence opens several avenues for an additional application of oenological tannins in the wine industry
and shed new light on the impact that oenological tannins might have on final aroma profil
Monitoring accumulation and degradation of polysulfides with the consequently hydrogen sulfide formation using ion chromatography and ultra highpressure liquid chromatography combined with fraction collection and high-resolution mass spectrometry
No full text
Riduzione del tasso alcolico dei vini: le tecniche disponibili.
No full textRiduzione del tasso alcolico dei vini: le tecniche disponibil
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
First evidence of the presence of S-cysteinylated and S-glutathionylated precursors in tannins
No full textTannins are widely used in winemaking and food and beverage preparation for the many different contributions they can give to the overall characteristics of the product (e.g., colour stability, mouthfeel and aromatic composition). Varietal thiols and their precursors are one of the most interesting research areas in food science and a lot of effort has been put to further the current understanding on their formation and on the impact of different production strategies on their concentration in the final product.
This paper reports the identification of two important thiol precursors (Cys-3MH and GSH-3MH) in commercial grape oenological tannins and, to the best of our knowledge, this information is reported here for the first time. This finding allows potential new perspectives in the winemaking and the food industry, offering the possibility of controlled additions of thiol precursors in pre-fermentative stages in order to tune the aroma profile of fermented product
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