Yeasts associated with the production of distilled alcoholic beverages

Distilled alcoholic beverages are produced firstly by fermenting sugars emanating from cereal starches (in the case of whiskies), sucrose-rich plants (in the case of rums), fructooligosaccharide-rich plants (in the case of tequila) or from fruits (in the case of brandies). Traditionally, such fermentations were conducted in a spontaneous fashion, relying on indigenous microbiota, including wild yeasts. In modern practices, selected strains of Saccharomyces cerevisiae are employed to produce high levels of ethanol together with numerous secondary metabolites (eg. higher alcohols, esters, carbonyls etc.) which greatly influence the final flavour and aroma characteristics of spirits following distillation of the fermented wash. Therefore, distillers, like winemakers, must carefully choose their yeast strain which will be very important in providing the alcohol content and the sensory profiles of spirit beverages. This Chapter discusses yeast and fermentation aspects associated with the production of selected distilled spirits and highlights similarities and differences with the production of wine

PCR anidado múltiple para detección de fitoplasmas y begomovirus identificados en cultivos de soya en Cuba

The objective of the work was to develop a nested multiplex PCR assay for the simultaneous detection of phytoplasmas and the begomoviruses identified in soybean in Cuba. Two pairs of specific primers to the begomoviruses Tobacco yellow crinkle virus (TbYCV) and Rhynchosia golden mosaic Yucatan virus (RhGMYuV) were designed, and they were used in conjunction with two pairs of universal primers for the generic detection of phytoplasms under established conditions. The evaluation of the optimal temperature for alignment of the primers to the template, the analytical sensitivity, and the specificity of the primers, critical parameters for the nested PCR assay for begomoviruses, were optimized. Critical parameters for the nested multiplex PCR assay, such as the evaluation of different combinations of concentrations of the primers designed with the conditions established for phytoplasm nPCR, the analytical sensitivity, and the intra and inter-assay repeatability, were also optimized. Performance parameters of the multiplex nPCR assay were determined. In the multiple assay, the fragments expected for TbYCV (988 kb), RhGMYuV (968 kb), and phytoplasms (1250 kb) were successfully amplified, confirming the simultaneous, sensitive and specific detection of these pathogens. The analytical parameters of the trial performance were over 90%. The multiple nested PCR assay here developed allows a sensitive, fast and low-cost detection of phytoplasmas sp. and begomoviruses that affect soybean in Cuba. These results are the first of this type for the country and provide new methodological elements for the validation of plant pathogen detection assays.El objetivo del presente trabajo fue desarrollar un ensayo de PCR múltiple anidado para la detección simultánea de fitoplasmas y los begomovirus identificados en cultivos de soya en Cuba. Se diseñaron dos parejas de cebadores específicos a los begomovirus Tobacco yellow crinkle virus (TbYCV) y Rhynchosia golden mosaic Yucatan virus (RhGMYuV) que se utilizaron, conjuntamente, con dos parejas de cebadores universales para la detección genérica de fitoplasmas bajo condiciones ya establecidas. Se optimizaron los parámetros críticos para el ensayo de PCR anidado para begomovirus que incluyeron: evaluación de la temperatura óptima de alineamiento de los cebadores al molde, sensibilidad analítica y la especificidad de los cebadores. Se optimizaron los parámetros críticos para el ensayo de PCR múltiple anidado; estos fueron: evaluación de diferentes combinaciones de concentraciones de los cebadores diseñados con las condiciones establecidas para nPCR de fitoplasmas, sensibilidad analítica y repetitividad intra e interensayo. Se determinaron los parámetros de desempeño del ensayo de nPCR múltiple. En el ensayo múltiple se amplificaron satisfactoriamente los fragmentos esperados para el TbYCV (988 kb), RhGMYuV (968 kb) y los fitoplasmas (1250 kb), confirmando la detección simultánea, sensible y específica de estos patógenos. Los parámetros analíticos de desempeño del ensayo fueron superiores a 90 %. El ensayo de PCR anidado múltiple desarrollado permite una detección sensible, rápida y de menor costo para la detección de los fitoplasmas y begomovirus que afectan el cultivo de soya en Cuba. Estos resultados son los primeros de este tipo para el país y aportan nuevos elementos metodológicos para la validación de ensayos de detección de patógenos de plantas