1,721,077 research outputs found
Investigation by High-Throughput Sequencing Methods of Microbiota Dynamics in Spontaneous Fermentation of Abruzzo (South Italy) Wines
Full text linkSpontaneous wine fermentation is a meaningful topic that cannot be disregarded among winemakers and consumers due to the peculiarity of the organoleptic profile that it confers to the wine. Nevertheless, in this process the activity of indigenous microorganisms might be a threat. We studied the evolution of the spontaneous fermentation process in a traditional Italian winery in order to understand the origin of spoilage microorganisms, and to characterize the peculiarity of the microbiota associated with spontaneous fermentation. Six Trebbiano and Montepulciano wine production chains were monitored by plate counts made by OIV methods and by Illumina MiSeq technique. Despite some compositional deficiencies, all grape musts were characterized by a highly concentrated microbial population. Non-Saccharomyces yeasts revealed an unexpected tolerance to ethanol, which has contributed to the evolution of alcoholic fermentation. Lactic bacteria were detectable from the very first steps of the winemaking process, with a prevalence of Leuconostoc spp. which is nowadays, rarely isolated in wine. The combination between culture-dependent and high-throughput sequencing (HTS) approaches allowed to estimate microbial diversity and growth dynamics in wine fermentations of different grape varieties and under different treatments; these results could be used by winemakers as a starting point to drive a more mindful, accurate and, controlled fermentation process and to set up the most suitable environmental conditions to enhance wine singularities
Biodiversity and oenological attitude of Saccharomyces cerevisiae strains isolated in the Montalcino district: biodiversity of S. cerevisiae strains of Montalcino wines
No full textThe biodiversity of Saccharomyces cerevisiae was studied in the Montalcino area (Italy). Two wineries were involved in the study, which compared the genotypic and oenological characteristics of the S. cerevisiae strains isolated in spontaneous fermentations. After isolation yeasts were identified by 26S rRNA gene sequence analysis, and S. cerevisiae strains were characterized through interdelta sequence analysis (ISA). Oenological tests were performed in synthetic grape must by varying the magnitude of the main wine-imiting factors. The evolution of alcoholic fermentation was monitored by measuring sugar consumption and flow cytometry. The results revealed the prevalence of S. cerevisiae from the third day of fermentation and the presence of a wide range of S. cerevisiae strains having ISA profiles characteristic of each winery. From an oenological point of view, the features of such strains, in terms of resistance to wine-limiting factors, seemed to be linked to the main oenological variables applied in the production process of each winery. Extreme fermentation temperatures and copper residues are the variables that mostly depress the yeast population, in terms of fermentation rate and cell viability. Flow cytometry revealed the different impact of limiting factors on the viability of yeast by the quantification of the ratio between live/dead yeast cells of each strain, suggesting different mechanisms of inhibition, for instance stuck of cell growth or cell killing, in response to the different stress factors
Biodiversità genetica e fisiologica, potenziale alterativo, di una popolazione di B. bruxellensis isolata da vini italiani
No full textB. bruxellensis è il principale microrganismo alterativo in ambito enologico, in grado di deprezzare fortemente i vini nei quali dovesse svilupparsi. Questo lievito è da sempre diffuso in cantina, ma i cambiamenti ambientali e tecnologici intervenuti negli ultimi anni ne hanno accentuato la pericolosità. Un approfondimento riguardo alla biodiversità intrinseca alla specie B. bruxellensis, e dunque al suo potenziale alterativo, è necessario per ottimizzare le strategie di controllo
Use of Lachancea thermotolerans and Saccharomyces cerevisiae isolated from manna ash products to improve quality of loquat beer
No full textGoing 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
Oenological characterisation of indigenous strains of S. cerevisiae isolated in a biodynamic winery in the Cortona DOC area
Full text linkGenotypic and technological characterisation of the S. cerevisiae population isolated in a biodynamic winery in the Cortona DOC area was performed to gain better knowledge of the variables that influence winemaking. The oenological performance of 11 S. cerevisiae strains was evaluated with physiological tests; strain typing was performed through analysis of interdelta sequences and 26S rDNA sequencing. The analysis revealed a remarkable variability in terms of S. cerevisiae strains, despite the homogeneity of wine features, underlining the high levels of biodiversity characterising biodynamic agriculture. Some strains were found in wines of different vintages, suggesting the presence of an established microbiota in the winery. Oenological tests demonstrated that while some yeasts provided reliable oenological performance, other strains were not able to accomplish prompt and effective alcoholic fermentation, or were characterised by spoilage characteristics, such as excessive production of volatile phenols or acetic acid. Indigenous strains of S. cerevisiae could be a useful instrument for reliable winemaking without altering the native microbiota of each oenological environment. However, characterisation of their oenological suitability, and the application of practices able to drive the evolution of microbiota, must be employed to reduce the risk of wine spoilage
Non-conventional yeasts (Starmerella lactis-condensi and Candida oleophila) and Lactic Acid Bacteria (Lactiplantibacillus plantarum and Oenococcus oeni) in sequentially inoculated fermentations: a strategy to improve aroma of Catarratto wine
No full textVariations 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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