Estudio de nuevas estrategias para la caracterización y optimización del envejecimiento de vinos y brandies de Jerez

Los vinos y Brandies de la zona de Jerez, gozan de una etapa de envejecimiento en barricas de roble, siguiendo el tradicional sistema de Solera y Criaderas que se traduce en importantes cambios en las características organolépticas del producto de partida. Es durante la etapa de envejecimiento cuando se producen numerosas transformaciones biológicas y físico-químicas entre las que podemos destacar: la evolución en el contenido en polifenoles junto a importantes modificaciones en el contenido en compuestos volátiles, así como otras modificaciones específicas de cada producto. Todos estos cambios van a venir favorecidos por el aporte de la madera de la bota y por la oxigenación moderada que el producto experimenta gracias a los microporos existentes en la misma. El papel activo de la madera en la elaboración de vinos y brandies de Andalucía es un hecho conocido y probado desde hace bastante tiempo, siendo el proceso de difusión de compuestos extraíbles uno de los principales responsables de los cambios que sufren las bebidas envejecidas. Aunque el Consejo Regulador del vino de Jerez, permite en determinados vinos que el envejecimiento se realice por añadas (envejecimiento estático), lo tradicional en la zona es el sistema dinámico de Solera y Criaderas, particular sistema de envejecimiento utilizado en Jerez, que implica: ¿Mantener las características del vino a lo largo del proceso de envejecimiento, ya que elimina las oscilaciones que tienen lugar entre las diferentes añadas. Este fenómeno presenta un gran interés de índole comercial al mantener homogénea la calidad de los vinos a lo largo de los años. De hecho si comparamos la evolución de un vino envejecido por este sistema con la evolución del mismo vino sometido a un sistema de añada observamos claras diferencias en cuanto a composición y homogeneidad de las mismas. ¿Activar el envejecimiento físico-químico, ya que homogeniza los gradientes de concentración que se producen en el interior de la bota por el fenómeno de permeabilidad selectiva, que tiene lugar en las paredes de la bota y aporta periódicamente pequeñas cantidades de aire al vino, activando de este modo los procesos oxidativos de envejecimiento de los mismos. En el caso del Brandy de Jerez, se mantiene el mismo sistema de envejecimiento, pero existen otros factores que influyen considerablemente en el producto final. Así el reglamento de la denominación específica, Brandy de Jerez, impone que los brandies sean envejecidos en barricas que previamente hayan servido para envejecer vinos de Jerez. Esta práctica aporta a los brandies que se envejecen en estas vasijas, características organolépticas que son propias de los vinos de Jerez, como son los Finos, Amontillados, Olorosos, Pedro Ximénez, etc. La etapa de envejecimiento es sin duda la fase definitiva en la elaboración de los vinos de Jerez, siendo la más prolongada desde el punto de vista temporal y en la que se perfilan las características organolépticas que van a dar lugar a la amplia tipología de vinos de Jerez. Lo mismo ocurre para el caso del Brandy d Por todo lo anteriormente expuesto en la presente tesis se ha planteado como objetivo general estudiar los vinos y brandies de Jerez en su relación al sistema de envejecimiento, abordando aspectos metodológicos (desarrollo de nuevas metodologías tanto para la caracterización de los vinos y brandies), la caracterización en sí de los vinos y brandies y la búsqueda de parámetros indicadores de su vejez. Para ello se han organizado los siguientes objetivos: a) Respecto a la metodología 1.Revisar la metodología analítica para buscar aquellos métodos más apropiados para la caracterización de vinos y brandies de Jerez. En este sentido se pretende buscar métodos más rápidos y fiables de los que se venían usando en nuestro laboratorio. Puesta a punto y validación de los nuevos métodos seleccionados. 2.Aplicación de técnicas analíticas de separación y aislamiento de compuestos fenólicos a vinos de Jerez, con la idea de obtener fracciones más sencillas que nos permitan identificar un mayor número de compuestos y poder aislar alguno de ellos y evaluar la capacidad antioxidante que aportan. b) Respecto a los sistemas de envejecimiento 3.Caracterizar un sistema de envejecimiento por Solera y Criaderas de Brandy de Jerez, con objeto de: por un lado, seleccionar aquellos parámetros analíticos que sirvan como parámetros discriminantes a la hora de clasificar las muestras en función de su vejez, y por otro lado, determinar la influencia del envinado de las botas sobre la calidad del producto. 4.Desarrollar y poner a punto un modelo alternativo de envejecimiento acelerado, con vistas a acelerar los procesos de envejecimiento manteniendo la calidad, y así contar con un test que nos permita explorar la potencialidad del uso de destilados de otras variedades de uvas diferentes de la habitualmente usada (Airen) para su envejecimiento como Brandy de Jerez. Para poder comparar la calidad de los productos así logrados se ha establecido un panel sensorial específico. 5.Estudiar el comportamiento de parámetros analíticos (polifenoles, poder antioxidante y color) relacionados con el periodo de envejecimiento en vino y Brandy de Jerez, su uso como indicadores de vejez, y la correlación entre ellos

Analytical Characterization and Sensory Analysis of Distillates of Di erent Varieties of Grapes Aged by an Accelerated Method

The wine spirits used for the elaboration of Brandy de Jerez are mainly obtained from wines produced from the Airen type of grape, which comes from the vineyards located in the region of La Mancha (Central Spain). This entails a limitation when achieving a product classified as "protected geographic designation". For that purpose, it is necessary that the grape used for the wine spirit comes from the area and not from Castile la Mancha, as has happened until now. Due to this fact, it is necessary to search for a possible alternative grape variety which allows the produced brandy to be eligible for a "protected geographic designation". For that purpose, an accelerated ageing process has been implemented with a method previously optimized to distillates obtained from wines from different varieties of grapes (Airen, Colombard, Corredera, Doradilla, Garrido Fino, Jaen blanco, Moscatel de Alejandria, Palomino Fino, Ugni Blanc, and Zalema) grown in the Jerez Area. They were evaluated, both from the analytical and sensory points of view. The distillates made from Jaen Blanco and Zalema have properties that make them interesting for future development and incorporation into oenological practice

Characterization and Di erentiation of Spanish Vinegars from Jerez and Condado de Huelva Protected Designations of Origin

Thirty one Jerez vinegar samples and 33 Huelva vinegar samples were analyzed for polyphenolic and volatile compound content in order to characterize them and attempt to di erentiate them. Sixteen polyphenolic compounds were quantified by means of ultraperformance liquid chromatography method with diode array detection (UPLC–DAD), and 37 volatile compounds were studied by means of stir bar sorptive extraction–gas chromatography–mass spectrometry (SBSE–GC–MS). Spectrophotometric CIELab parameters were also measured for all the samples. The results obtained from the statistical multivariate treatment of the data evidenced a clear di erence between vinegars from the two geographical indications with regard to their polyphenolic content, with Jerez vinegars exhibiting a greater phenolic content. Di erentiation by the volatile compound content was, however, not so evident. Nevertheless, a considerable di erentiation between the two groups of vinegars based on their volatile fraction was achieved. This may bring to light the grape varieties and geographical factors that have a clear influence on such di erences

Nucleotide sequence and transfer properties of two novel types of Actinobacillus pleuropneumoniae plasmids carrying the tetracycline resistance gene tet(H)

17 p.The aim of this study is to analyze the sequence and transfer properties of two tetracycline resistance plasmids found in clinical isolates of Actinobacillus pleuropneumoniae in order to assert their role in the spread of tetracycline resistenceS

Aroma of Sherry Products: A Review

Jerez (Sherry) is a well-known wine-producing region located in southern Spain, where world-renowned oenological products such as wines, vinegars, and brandies are produced. There are several factors that provide characteristic physical, chemical, and sensory properties to the oenological products obtained in this Sherry region: the climate in the area with hot summers, mild winters, and with limited rainfall; the raw material used consisting on Palomino Fino, Moscatel, and Pedro Ximénez white grape varieties; the special vinification with fortified wines; and aging techniques such as a dynamic system of biological or oxidative aging. These special organoleptic characteristics are responsible for, among others, the aromatic profile of the wines, vinegars and brandies from the area, which explains why this is a subject that has been extensively researched over the years. This bibliographic review aims to compile the different scientific contributions that have been found to date, in relation with the aroma of the oenological products from the Sherry area (dry wines, sweet wines, vinegars, and brandies). We have mainly focused on the different analytical methodologies used and on the main analytes of interest

Generation and analysis of transcriptomic resources for a model system on the rise: the sea anemone Aiptasia pallida and its dinoflagellate endosymbiont

<p>Abstract</p> <p>Background</p> <p>The most diverse marine ecosystems, coral reefs, depend upon a functional symbiosis between cnidarian hosts and unicellular dinoflagellate algae. The molecular mechanisms underlying the establishment, maintenance, and breakdown of the symbiotic partnership are, however, not well understood. Efforts to dissect these questions have been slow, as corals are notoriously difficult to work with. In order to expedite this field of research, we generated and analyzed a collection of expressed sequence tags (ESTs) from the sea anemone <it>Aiptasia pallida </it>and its dinoflagellate symbiont (<it>Symbiodinium </it>sp.), a system that is gaining popularity as a model to study cellular, molecular, and genomic questions related to cnidarian-dinoflagellate symbioses.</p> <p>Results</p> <p>A set of 4,925 unique sequences (UniSeqs) comprising 1,427 clusters of 2 or more ESTs (contigs) and 3,498 unclustered ESTs (singletons) was generated by analyzing 10,285 high-quality ESTs from a mixed host/symbiont cDNA library. Using a BLAST-based approach to predict which unique sequences derived from the host versus symbiont genomes, we found that the contribution of the symbiont genome to the transcriptome was surprisingly small (1.6–6.4%). This may reflect low levels of gene expression in the symbionts, low coverage of alveolate genes in the sequence databases, a small number of symbiont cells relative to the total cellular content of the anemones, or failure to adequately lyse symbiont cells. Furthermore, we were able to identify groups of genes that are known or likely to play a role in cnidarian-dinoflagellate symbioses, including oxidative stress pathways that emerged as a prominent biological feature of this transcriptome. All ESTs and UniSeqs along with annotation results and other tools have been made accessible through the implementation of a publicly accessible database named AiptasiaBase.</p> <p>Conclusion</p> <p>We have established the first large-scale transcriptomic resource for <it>Aiptasia pallida </it>and its dinoflagellate symbiont. These data provide researchers with tools to study questions related to cnidarian-dinoflagellate symbioses on a molecular, cellular, and genomic level. This groundwork represents a crucial step towards the establishment of a tractable model system that can be utilized to better understand cnidarian-dinoflagellate symbioses. With the advent of next-generation sequencing methods, the transcriptomic inventory of <it>A. pallida </it>and its symbiont, and thus the extent of AiptasiaBase, should expand dramatically in the near future.</p

Coral life history and symbiosis: Functional genomic resources for two reef building Caribbean corals, Acropora palmata and Montastraea faveolata

<p>Abstract</p> <p>Background</p> <p>Scleractinian corals are the foundation of reef ecosystems in tropical marine environments. Their great success is due to interactions with endosymbiotic dinoflagellates (<it>Symbiodinium </it>spp.), with which they are obligately symbiotic. To develop a foundation for studying coral biology and coral symbiosis, we have constructed a set of cDNA libraries and generated and annotated ESTs from two species of corals, <it>Acropora palmata </it>and <it>Montastraea faveolata</it>.</p> <p>Results</p> <p>We generated 14,588 (<it>Ap</it>) and 3,854 (<it>Mf</it>) high quality ESTs from five life history/symbiosis stages (spawned eggs, early-stage planula larvae, late-stage planula larvae either infected with symbionts or uninfected, and adult coral). The ESTs assembled into a set of primarily stage-specific clusters, producing 4,980 (<it>Ap</it>), and 1,732 (<it>Mf</it>) unigenes. The egg stage library, relative to the other developmental stages, was enriched in genes functioning in cell division and proliferation, transcription, signal transduction, and regulation of protein function. Fifteen unigenes were identified as candidate symbiosis-related genes as they were expressed in all libraries constructed from the symbiotic stages and were absent from all of the non symbiotic stages. These include several DNA interacting proteins, and one highly expressed unigene (containing 17 cDNAs) with no significant protein-coding region. A significant number of unigenes (25) encode potential pattern recognition receptors (lectins, scavenger receptors, and others), as well as genes that may function in signaling pathways involved in innate immune responses (toll-like signaling, NFkB p105, and MAP kinases). Comparison between the <it>A. palmata </it>and an <it>A. millepora </it>EST dataset identified ferritin as a highly expressed gene in both datasets that appears to be undergoing adaptive evolution. Five unigenes appear to be restricted to the Scleractinia, as they had no homology to any sequences in the nr databases nor to the non-scleractinian cnidarians <it>Nematostella vectensis </it>and <it>Hydra magnipapillata</it>.</p> <p>Conclusion</p> <p>Partial sequencing of 5 cDNA libraries each for <it>A. palmata </it>and <it>M. faveolata </it>has produced a rich set of candidate genes (4,980 genes from <it>A. palmata</it>, and 1,732 genes from <it>M. faveolata</it>) that we can use as a starting point for examining the life history and symbiosis of these two species, as well as to further expand the dataset of cnidarian genes for comparative genomics and evolutionary studies.</p

Discriminant ability of phenolic compounds and short chain organic acids profiles in the determination of quality parameters of Brandy de Jerez

Brandy de Jerez is the most produced spirit in Spain. The rules of its Regulatory Council require the spirit to age in American oak casks that have previously contained any kind of sherry wine. This use, called seasoning, releases wine compounds into the spirit. Because of the differences among sherries, the organoleptic features of a brandy will be significantly different from any other depending on the seasoning. In addition, its specific features make it different from any other spirit. The chromatographic profiles of Brandy de Jerez are reported to be different depending on the seasonings through their ageing process. Different types of Brandy de Jerez have been characterised, regarding their seasoning, using chromatographic techniques. Applying statistical analysis, correlations between the chromatographic profiles and the seasonings have risen up. In addition, the profiles have demonstrated to possess a high degree of correlation with the ageing time of the samples

HPLC-DAD-MS and Antioxidant Profile of Fractions from Amontillado Sherry Wine Obtained Using High-Speed Counter-Current Chromatograph

n the present work, the polyphenolic profile of a complex matrix such as Amontillado sherry has been processed by means of high-speed counter-current chromatography (HSCCC) and characterized by HPLC-DAD-MS. An Amberlite XAD-7 column was used to obtain the wine extract, and three different biphasic solvent systems were applied for HSCCC separation: MTBE (methyl tert-butyl ether)/n-butanol/acetonitrile/water (1.1/3/1.1/5+0.1% trifluoroacetic acid), MTBE/n-butanol/acetonitrile/water (2/2/1/5), and hexane/ethyl acetate/ethanol/water (1/5/1/5). As a result, 42 phenolic compounds and furanic derivatives have been identified by means of HPLC-DAD-MS, with 11 of them being identified for the first time in Sherry wines: 3-feruloylquinic acid, isovanillin, ethyl vanillate, furoic acid, dihydro-p-coumaric acid, 6-O-feruloylglucose, ethyl gallate, hydroxytyrosol, methyl protocatechuate, homoveratric acid and veratraldehyde. In addition, the antioxidant capacity (ABTS) of the obtained fractions was determined, revealing higher values in those fractions in which compounds such as gallic acid, protocatechuic acid, protocatechualdehyde, trans-caftaric acid, syringic acid, isovanillin or tyrosol, among others, were present. This is the first time that HSCCC has been used to characterize the phenolic composition of Sherry wines

Membrane Partitioning: “Classical” and “Nonclassical” Hydrophobic Effects

The free energy of transfer of nonpolar solutes from water to lipid bilayers is often dominated by a large negative enthalpy rather than the large positive entropy expected from the hydrophobic effect. This common observation has led to the idea that membrane partitioning is driven by the “nonclassical” hydrophobic effect. We examined this phenomenon by characterizing the partitioning of the well-studied peptide melittin using isothermal titration calorimetry (ITC) and circular dichroism (CD). We studied the temperature dependence of the entropic (−TΔS) and enthalpic (ΔH) components of free energy (ΔG) of partitioning of melittin into lipid membranes made of various mixtures of zwitterionic and anionic lipids. We found significant variations of the entropic and enthalpic components with temperature, lipid composition and vesicle size but only small changes in ΔG (entropy–enthalpy compensation). The heat capacity associated with partitioning had a large negative value of about −0.5 kcal mol−1 K−1. This hallmark of the hydrophobic effect was found to be independent of lipid composition. The measured heat capacity values were used to calculate the hydrophobic-effect free energy ΔGhΦ, which we found to dominate melittin partitioning regardless of lipid composition. In the case of anionic membranes, additional free energy comes from coulombic attraction, which is characterized by a small effective peptide charge due to the lack of additivity of hydrophobic and electrostatic interactions in membrane interfaces [Ladokhin and White J Mol Biol 309:543–552, 2001]. Our results suggest that there is no need for a special effect—the nonclassical hydrophobic effect—to describe partitioning into lipid bilayers