1,720,967 research outputs found
Dual Role of Yeasts and Filamentous Fungi in Fermented Sausages
No full textThis contribution aims to review the presence and the potential double role-positive or beneficial and negative or harmful-of fungi in fermented sausages as well as their use as starter cultures. Traditionally, studies have been focused on lactic acid bacteria; however, over the years, interest in the study of fungi has increased. The important contribution of yeasts and filamentous fungi to the quality and safety of fermented sausages has emerged from reviewing the literature regarding these fermented products. In conclusion, this review contributes to the existing literature by considering the double role of filamentous fungi and yeasts, the global fermented sausage market size, the role and use of starters, and the starters mainly present in the worldwide market, as well as the main factors to take into account to optimize production. Finally, some suggestions for future broadening of the sector are discussed
Genetic Improvement of wine yeasts for opposite adsorption activity of phenolics and ochratoxin A during red winemaking
No full textThe aim of this research was to acquire new strains of Saccharomyces cerevisiae exhibiting opposite characteristics of cell wall adsorption: very high adsorption activity toward the ochratoxin A, very low adsorption activity toward the pigmented phenolic compounds contained in musts from black grapes. For this purpose, starting from 313 strains of Saccharomyces cerevisiae, 12 strains were pre-selected and used to obtain 27 intraspecific hybrids. Eleven crosses out of 27 were validated as hybrids; the best five hybrids were used in guided winemaking at four Calabrian wineries. The employed experimental protocol has allowed to select yeast strains for their different adsorption activity, improving the strains by spore clone selection and construction of intraspecific hybrids. These results suggest an efficacious way to improve the characteristics of interest in wine yeasts
Wine colour adsorption phenotype: An inheritable quantitative trait loci of yeasts
No full textAbstractAims: In this work, a population of 88 descendants derived from three wine strains of Saccharomyces cerevisiae was tested for the enological trait 'wine colour adsorption' (WCA) to evaluate its inheritability.Methods and Results: The WCA phenotype was tested on plate agar medium specifically formulated for the purpose. After 10 days of anaerobic incubation at 28°C, a computer-assisted assessment of WCA aptitude of the yeasts was carried out. The biomass colour – ranging from white to dark brown – reflects the adsorption of grape pigments: white and dark brown biomass colour corresponds to low and high adsorption, respectively. In order to confirm biomass colour results, microvinification trials using red must were performed, and the obtained wines were analysed.Conclusions: The analysis of the progeny demonstrated that the enological trait WCA is inheritable and polygenic.Significance and Impact of the Study: A way to describe the polygenic effect of the WCA trait has been found, also showing that this trait is inheritable. The impact of the work revolves more around the large-scale screening method, which could then assist in breeding wine yeast, and can also be used as a scientific tool to investigate WCA trait
Ochratoxin A adsorption phenotype: an inheritable yeast trait
Get PDFThis study aimed to evaluate the inheritance of the trait ochratoxin A adsorption in two wine
strains of Saccharomyces cerevisiae and their 46 descendants. Each strain was inoculated in
triplicate in test tubes containing 10 ml of must obtained from the Calabrian Zibibbo white grape
variety, artifi cially contaminated with ochratoxin A to reach a total content of 4.10 ng/ml. The
microvinifi cation trials were performed at 25°C. After 30 days, ochratoxin A values ranged from
0.74 to 3.18 ng/ml, from 0.01 to 2.69 ng/ml, and from 0.60 to 2.95 ng/ml respectively in wines, in
lees after washing, and in the saline solution used to wash the lees. The analysis of OTA in wines
was performed to fi nd the residual toxin content after yeast activity, thus obtaining technological
evidence of yeast infl uence on wine detoxifi cation. The analysis of OTA in lees after washing was
performed to distinguish the OTA linked to cells. The analysis of OTA in the saline solution used
to wash the lees was performed to distinguish the OTA adsorbed on yeast cell walls and removed
by washing, thus focusing on the adsorption activity of wine yeast through electrostatic
and ionic interactions between parietal mannoproteins and OTA. Ploidy of the two parental
strains was controlled by fl ow cytometry. Results demonstrated that the ochratoxin A adsorption
is genetically controlled and is a polygenic inheritable trait of wine yeasts. The majority of the
descendants are characterized by a great and signifi cant diversity compared to their parents.
Both the parental strains had genome sizes consistent with their being diploid, so validating the
observed results. These fi ndings constitute an initial step to demonstrate the mechanisms of
inheritance and establish breeding strategies to improve the ochratoxin A adsorption trait in wine
yeasts. This will allow a decrease in the ochratoxin A content of contaminated musts during
winemaking, by using genetically improved wine yeasts
Cultivable microbial ecology and aromatic profile of “mothers” for Vino cotto wine production
No full textThe aim of the present study was to assess the cultivable microbiota of “mothers” of Vino cotto collected from production of different years 1890, 1895, 1920, 1975, 2008. A total of 73 yeasts and 81 bacteria were isolated. Starmerella lactis-condensi, Starmerella bacillaris, Hanseniaspora uvarum, Saccharomyces cerevisiae, Hanseniaspora guillermondi and Metschnikowia pulcherrima were identified. Bacteria isolates belonged to lactic acid bacteria (Lactiplantibacillus plantarum and Pediococcus pentosaceus) and acetic acid bacteria (Gluconobacter oxydans). Remarkable biodiversity was observed for Starm. bacillaris, as well as L. plantarum and G. oxydans. Organic acids and volatile compounds were also determined. Malic and succinic acids were the main ones with values ranging from 8.49 g/L to 11.76 g/L and from 4.15 g/L to 7.73 g/L respectively, while citric acid was present at low concentrations (<0.2 g/L) in all samples. Esters and higher alcohols were the main volatile compounds detected followed by alkanes. This study permits to better understand the microbial communities associated to this product and could be considered a starting point for the definition of tailored starter cultures to improve the quality of Vino cotto preserving its typical traits
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
Antagonistic activity against foodborne-pathogens of Lactic Acid bacteria from Calabrian raw milk cheeses
No full textVariations 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
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