•Application of yeast Hanseniaspora vineae in real wine co-fermentation.•H. vineae and spontaneous fermentations showed higher flavour intensity and diversity.•Genetic strains identification showed ...increased diversity compared to conventional treatment.•Increased formation of esters and decrease formation of alcohols may explain fruit intensity.
Discovery, characterisation and use of novel yeast strains for winemaking is increasingly regarded as a way for improving quality and to provide variation, including subtle characteristic differences in fine wines. The objective of this work was to evaluate the use of a native apiculate strain, selected from grapes, Hanseniaspora vineae (H. vineae) 02/5A. Fermentations were done in triplicate, working with 225L oak barrels, using a Chardonnay grape must. Three yeast fermentation strategies were compared: conventional inoculation with a commercial Saccharomyces cerevisiae strain, ALG 804, sequential inoculation with H. vineae and then strain ALG 804 and spontaneous fermentation. Yeast strain identification was performed during fermentation, in which the apiculate strain was found to be active, until 9% of alcohol in volume, for the co-fermentation and the spontaneous fermentation was completed by three native S. cerevisiae strains. Basic winemaking parameters and some key chemical analysis, such as concentration of glycerol, biogenic amines, organic acids, and aroma compounds were analysed. Sensory analysis was done using a trained panel and further evaluated with professional winemakers. Sequential inoculation with H. vineae followed by S. cerevisiae resulted in relatively dry wines, with increased aroma and flavour diversity compared with wines resulting from inoculation with S. cerevisiae alone. Wines produced from sequential inoculations were considered, by a winemaker’s panel, to have an increased palate length and body. Characteristics of wines derived from sequential inoculation could be explained due to significant increases in glycerol and acetyl and ethyl ester flavour compounds and relative decreases in alcohols and fatty acids. Aroma sensory analysis of wine character and flavour, attributed to winemaking using H. vineae, indicated a significant increase in fruit intensity described as banana, pear, apple, citric fruits and guava. GC analysis of the relative accumulation of 23 compounds to significantly different concentrations for the three fermentation strategies is discussed in relation to aroma compound composition.
Recently, the increase in microbreweries and the consequent production of craft beers have reached exponential growth. The interest in non-conventional yeasts for innovation and a unique selling ...feature in beer fermentation is increasing. This work studied the autochthonous Saccharomyces and non-Saccharomyces yeasts, isolated from various food sources, with the ability to modify and improve the fermentative and aromatic profiles during alcoholic fermentation. The ability to ferment maltose and produce desirable aroma compounds were considered as the key characters for the screening selection. A synthetic beer wort was developed for this purpose, to simulate beer wort composition.
A total of forty-seven yeast strains belonging to different genera were analysed according to their fermentation profile, volatile compounds production and sensory analysis. Three native strains of Saccharomyces cerevisiae, Zygoascus meyerae and Pichia anomala were selected to evaluate their aromatic profile in single and mixed fermentations. The strains produced 4-vinylguaiacol, β-phenylethyl alcohol, and isoamyl alcohol at levels significantly above the sensory threshold, making them interesting for wheat and blond craft beer styles. The native Hanseniaspora vineae was also included in a co-fermentation treatment, resulting in a promising yeast to produce fruity beers.
•A synthetic beer wort was developed to simulate beer wort composition.•Z. meyerae, P. anomala and H. vineae were the selected non-conventional yeasts.•Aroma compounds produced were promising for wheat and blond craft beer styles.•High ester production by Hanseniaspora vineae is promising for fruity beers.
Resumen
La variedad Tannat desde el punto de vista del aroma, resulta una variedad neutra pero capaz de aportar precursores aromáticos que son de interés en la elaboración de vinos de guarda. Los ...principales precursores aromáticos presentes son compuestos glicosidados y carotenoides. Durante 3 vendimias consecutivas se estudió el contenido de precursores aromáticos de 8 clones comerciales de Tannat (ENTAV-INRA: 398, 399, 472, 474, 475, 717, 794 Y 944). En base a los resultados obtenidos se seleccionaron los clones 717 y 474 por su alta y baja performance en la producción de precursores glicosidados. En la siguiente vendimia se estudió el comportamiento de precursores glicosidados (SPE-GC-MS) y carotenoides (HPLC-DAD) en los clones seleccionados durante 4 estadíos de madurez de la uva, donde se identificaron 14 xantofilas y 1 caroteno. Se encontraron diferencias significativas en el contenido de carotenoides entre los dos clones estudiados a lo largo del período de maduración. Mientras que su degradación no presentó diferencias significativas. Conjuntamente se identificaron 10 norisoprenoides glicosidados en la uva de los clones estudiados pero el contenido de estos no presentó diferencias significativas entre los clones durante está vendimia. Las diferencias entre los clones 717 y 474 son tales que no se expresan todos los años teniendo variabilidad con el año y donde el clima juega un rol fundamental.
Abstract
From the viewpoint of aroma, the Tannat is a neutral variety but it is capable of providing aromatic precursors that are of interest in the production of wines for ageing. The main aromatic precursors present are glycosidic compounds and carotenoids. The content of aromatic precursors of 8 commercial Tannat clones (ENTAV-INRA: 398, 399, 472, 474, 475, 717, 794 and 944) was studied during 3 consecutive harvests. Based on the results obtained, clones 717 and 474 were selected for their high and low performance in the production of glycosidic precursors. In the following vintage, the behaviour of glycosidic precursors (SPE-GC-MS) and carotenoids (HPLC-DAD) was studied in the selected clones during 4 stages of grape maturity, where 14 xanthophylls and 1 carotene were identified. Significant differences in carotenoid content were found between the two clones studied throughout the ripening period. While their degradation did not show significant differences. Jointly, 10 glycosidised norisoprenoids were identified in the grapes of the clones studied, but the content of these did not show significant differences between the clones during this harvest. The differences between clones 717 and 474 are such that they are not expressed every year, having variability with the year and where climate plays a fundamental role.
Resumen
En este trabajo se buscó a través de la combinación de 2 estrategias reducir el contenido de alcohol en vinos de la variedad Tannat. La primera estrategia consistió en el screening dentro de ...clones uruguayos de Tannat Con este fin se muestrearon durante tres vendimias consecutivas 10 clones uruguayos de Tannat y se utilizó como referencia el clon francés 717 en viñedos. De los clones estudiados 4 presentaron durante la vendimia 2023 un contenido significativamente inferior de alcohol que el clon 717, manteniendo los componentes responsables de su calidad sensorial (aromas glicosidados, antocianos totales). Mientras que la segunda estrategia fue realizar un screening de levaduras no-
Saccharomyces
nativas aisladas de viñedos uruguayos para utilizar en conjunto con la cepa
Saccharomyces cerevisiae
Lalvin BM4x4 Lalleman (utilizada como referencia para vinificar vino Tannat). Se estudió el comportamiento de 4 géneros de levaduras (
Candida zemplinina, Metschnikowia pulcherrima, Metschnikowia fructicola y Hanseniaspora uvarum
), en microvinificaciones en símil vino. Estas estrategias fueron seleccionada por que además de permitir la reducción de alcohol en vinos Tannat en forma conjunta le aportan una identidad propia de nuestro país.
The aim of this study was to reduce the alcohol content of Tannat wines through a combination of two strategies. The first strategy consisted of screening within Uruguayan Tannat clones. To this purpose, 10 Uruguayan Tannat clones were sampled during three consecutive vintages and the French clone 717 was used as a reference in vineyards. Of the clones studied, 4 showed significantly lower alcohol content than clone 717 during the 2023 vintage, while maintaining the components responsible for their sensory quality (glycosidic aromas, total anthocyanins), while the second strategy was to screen native non-Saccharomyces yeasts isolated from Uruguayan vineyards for use in conjunction with the
Saccharomyces cerevisiae
Lalvin BM4x4 Lalleman strain (used as a reference for vinifying Tannat wine). The behaviour of 4 yeast genera (
Candida zemplinina, Metschnikowia pulcherrima, Metschnikowia fructicola and Hanseniaspora uvarum
) was studied in wine-like microvinifications. These strategies were selected because they allow the reduction of alcohol in Tannat wines and, together, they give the wine a unique character of our country.
Flavour and some compounds associated with wine colour are known to be yeast strain-dependent. These metabolites are important for the sensory quality of wines, studies searching for increase aroma ...and color are a key area today in winemaking. The aim of this work was to study the oenological potential of the two main strains of
Hanseniaspora vineae,
native to Uruguay to better understand their successful application at winery level. It is known that these strains contribute with extracellular proteases and β-glucosidase enzyme activities that might increase cell lysis and flavor depending in grape varieties. Application and nutrient management of the process of these strains in production of white wines (Chardonnay, Macabeo and Petit Manseng) and red wine Tannat are discussed. Wines were evaluated to determine the volatile compounds composition and their effect compared to conventional processes. Low production of short and medium chain fatty acids and ethyl esters, and high production of acetate esters and isoprenoids are found compared to
S. cerevisiae
strains. The most outstanding characteristic of the species
H. vineae
was the production of benzenoids, phenylpropanoids and acetate esters. This behavior was reflected in the sensory evaluation, where all the fermentations performed with
H. vineae
were considered superior compared to
Saccharomyces cerevisiae
wine strains.
The objective of this work is to demonstrate if the hexaprenyl pyrophosphate synthetase Coq1p might be involved in monoterpenes synthesis in Saccharomyces cerevisiae, although its currently known ...function in yeast is to catalyze the first step in ubiquinone biosynthesis. However, in a BY4743 laboratory strain, the presence of an empty plasmid in a chemically defined grape juice medium results in a statistically significant increase of linalool, (E)-nerolidol and (E,E)-farnesol. When COQ1 is overexpressed from a plasmid, the levels of the volatile isoprenoids are further increased. Furthermore, overexpression of COQ1 in the same genetic context but with a mutated farnesyl pyrophosphate synthetase (erg20 mutation K197E), results in statistically significant higher levels of linalool (above 750 μg/L), geraniol, α-terpineol, and the sesquiterpenes, farnesol and nerolidol (total concentration of volatile isoprenoids surpasses 1300 μg/L). We show that the levels of monoterpenes and sesquiterpenes that S. cerevisiae can produce, in the absence of plant genes, depend on the composition of the medium and the genetic context. To the best of our knowledge, this is the highest level of linalool produced by S. cerevisiae up to now. Further research will be needed for understanding how COQ1 and the medium composition might interact to increase flavor complexity of fermented beverages.
•Coq1p might be involved in monoterpenes synthesis by S. cerevisiae.•An empty plasmid in a defined medium results in increased isoprenoid formation.•COQ1 overexpression in an erg20 mutant results in the highest level of yeast linalool.•Vitis varietal flavors might be significantly increased by yeast without plant genes.
This paper is a tutorial on the positive realization problem, that is the problem of finding a positive state-space representation of a given transfer function and characterizing existence and ...minimality of such representation. This problem goes back to the 1950s and was first related to the identifiability problem for hidden Markov models, then to the determination of internal structures for compartmental systems and later embedded in the more general framework of positive systems theory. Within this framework, developing some ideas sprang in the 1960s, during the 1980s, the positive realization problem was reformulated in terms of a geometric condition which was recently exploited as a tool for finding the solution to the existence problem and providing partial answers to the minimality problem. In this paper, the reader is carried through the key ideas which have proved to be useful in order to tackle this problem. In order to illustrate the main results, contributions and open problems, several motivating examples and a comprehensive bibliography on positive systems organized by topics are provided.
Flavour and some compounds associated with wine colour are known to be yeast strain-dependent. These metabolites are important for the sensory quality of wines, studies searching for increase aroma ...and color are a key area today in winemaking. The aim of this work was to study the oenological potential of the two main strains of Hanseniaspora vineae,native to Uruguay to better understand their successful application at winery level. It is known that these strains contribute with extracellular proteases and β-glucosidase enzyme activities that might increase cell lysis and flavor depending in grape varieties. Application and nutrient management of the process of these strains in production of white wines (Chardonnay, Macabeo and Petit Manseng) and red wine Tannat are discussed. Wines were evaluated to determine the volatile compounds composition and their effect compared to conventional processes. Low production of short and medium chain fatty acids and ethyl esters, and high production of acetate esters and isoprenoids are found compared to S. cerevisiaestrains. The most outstanding characteristic of the species H. vineaewas the production of benzenoids, phenylpropanoids and acetate esters. This behavior was reflected in the sensory evaluation, where all the fermentations performed with H. vineaewere considered superior compared to Saccharomyces cerevisiaewine strains.
Microwave thermal ablation (MTA) is a minimally invasive therapeutic technique aimed at destroying pathologic tissues through a very high temperature increase induced by the absorption of an ...electromagnetic field at microwave (MW) frequencies. Open problems, which are delaying MTA applications in clinical practice, are mainly linked to the extremely high temperatures, up to 120 °C, reached by the tissue close to the antenna applicator, as well as to the ability of foreseeing and controlling the shape and dimension of the thermally ablated area. Recent research was devoted to the characterisation of dielectric, thermal and physical properties of tissue looking at their changes with the increasing temperature, looking for possible developments of reliable, automatic and personalised treatment planning. In this paper, a review of the recently obtained results as well as new unpublished data will be presented and discussed.
There is a limited understanding of how diarrhoeal cases across other household members influence the likelihood of diarrhoea in young children (aged 1-4 years).
We surveyed 16,025 individuals from ...3421 households in 17 villages in Uganda. Using logistic regressions with standard errors clustered by household, diarrhoeal cases within households were used to predict diarrhoeal outcomes in young children. Regressions were adjusted for socio-demographic, water, sanitation, and hygiene (WASH), and ecological covariates. Selection bias for households with (1632/3421) and without (1789/3421) young children was examined.
Diarrhoeal prevalence was 13.7% (2118/16,025) across all study participants and 18.5% (439/2368) in young children. Young children in households with any other diarrhoeal cases were 5.71 times more likely to have diarrhoea than young children in households without any other diarrhoeal cases (95% CI: 4.48-7.26), increasing to over 29 times more likely when the other diarrhoeal case was in another young child (95% CI: 16.29-54.80). Diarrhoeal cases in older household members (aged ≥ 5 years) and their influence on the likelihood of diarrhoea in young children attenuated with age. School-aged children (5-14 years) had a greater influence on diarrhoeal cases in young children (Odds Ratio 2.70, 95% CI: 2.03-3.56) than adults of reproductive age (15-49 years; Odds Ratio 1.96, 95% CI: 1.47-2.59). Diarrhoeal cases in individuals aged ≥ 50 years were not significantly associated with diarrhoeal outcomes in young children (P > 0.05). These age-related differences in diarrhoeal exposures were not driven by sex. The magnitude and significance of the odds ratios remained similar when odds ratios were compared by sex within each age group. WASH factors did not influence the likelihood of diarrhoea in young children, despite influencing the likelihood of diarrhoea in school-aged children and adults. Households with young children differed from households without young children by diarrhoeal prevalence, household size, and village WASH infrastructure and ecology.
Other diarrhoeal cases within households strongly influence the likelihood of diarrhoea in young children, and when controlled, removed the influence of WASH factors. Future research on childhood diarrhoea should consider effects of diarrhoeal cases within households and explore pathogen transmission between household members.
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