Caracterización fenólica de uvas del cultivar carménère y su relación con la sensación de astrigencia

Tras su desaparición en Europa y redescubrimiento en Chile (1994), Carménère (familia Carmenet) es hoy la variedad vinífera emblemática de los vinos chilenos. Carménère difiere de otros Carmenets en la composición fenólica de semillas ((-)-epicatequina, epicatequina-3-O-galato, ácido gálico, procianidinas diméricas esterificadas con ácido gálico y porcentaje de galoilación) y hollejos (antocianos y flavonoides totales). Se estudió la interacción entre proteínas (salivales y albúmina) y taninos mediante implementación de método de observación de a) precipitación de proteínas y b) inhibición de la difusión de proteínas en suspensión sobre láminas de celulosa, ambas producidas por taninos. También su correspondencia con astringencia (panel sensorial). Se observó relación estrecha entre interacción proteínas salivales-taninos y percepción de astringencia e influencia del etanol y pH sobre ambos fenómenos. Finalmente, se caracterizó cambios progresivos en la reactividad de extractos fenólicos de semillas y hollejos Carménère con proteínas salivales y en la astringencia durante la maduración.After disappearing in Europe and rediscovery in Chile (1994), Carménère (Carmenet's family) has become the emblematic variety of Chilean wines. Carménère has been found to differ from other Carmenets in the phenolic composition of both seeds ((-)-epicatechin, epicatechin-3-O-gallate, gallic acid, gallic esters of dimeric procyanidins and percentage of galloylation) and skins (anthocyans and total flavonoids). Interaction of proteins (salivary and seroalbumin) and tannins was studied by setting a method for observing the effect of tannins on a) protein precipitation and b) inhibition of diffusion on cellulose membranes displayed by suspended proteins. Also, correspondence of both phenomena with astringency perception (sensory panel) was assessed. A close association between salivary protein-tannins interaction and astringency perception was observed together with ethanol- and pH-dependences of either phenomenom. Lastly, progressive changes in reactivity towards salivary proteins displayed by phenol compounds extracted from Carménère seeds and skins at various times during maturation were observed

Modelling phenolic and technological maturities of grapes by means of the multivariate relation between organoleptic and physicochemical properties

The ripeness of grapes at the harvest time is one of the most important parameters for obtaining high quality red wines. Traditionally the decision of harvesting is to be taken only after analysing sugar concentration, titratable acidity and pH of the grape juice (technological maturity). However, these parameters only provide information about the pulp ripeness and overlook the real degree of skins and seeds maturities (phenolic maturity). Both maturities, technological and phenolic, are not simultaneously reached, on the contrary they tend to separate depending on several factors: grape variety, cultivar, adverse weather conditions, soil, water availability and cultural practices. Besides, this divergence is increasing as a consequence of the climate change (larger quantities of CO2, less rain, and higher temperatures). 247 samples collected in vineyards representative of the qualified designation of origin Rioja from 2007 to 2011 have been analysed. Samples contain the four grape varieties usual in the elaboration of Rioja wines (‘tempranillo’, ‘garnacha’, ‘mazuelo’ and ‘graciano’). The present study is the first systematic investigation on the maturity of grapes that includes the organoleptic evaluation of the degree of grapes maturity (sugars/acidity maturity, aromatic maturity of the pulp, aromatic maturity of the skins and tannins maturity) together with the values of the physicochemical parameters (probable alcohol degree, total acidity, pH, malic acid, K, total index polyphenolics, anthocyans, absorbances at 420, 520 and 620 nm, colour index and tartaric acid) determined over the same samples. A varimax rotation of the latent variables of a PLS model between the physicochemical variables and the mean of four sensory variables allows identifying both maturities. Besides, the position of the samples in the first plane defines the effect that the different factors exert on both phenolic and technological maturitiesMinisterio de Economía y Competitividad (CTQ2011-26022) and Junta de Castilla y León (BU108A11-2

Em busca de marcadores sensoriais por entre a composição do vinho tinto: um estudo nacional inovador

The objective of this work was to verify the signaling/profiling potential of wine compounds and the physicochemical and bioclimatic winerelated measurements on a nationwide sensory scale of red wine typicality. Color tonality evolved from violet-purple in cooler northern regions to ruby-garnet in hotter southern regions. Acidity and astringency were enhanced from south to north. Conversely, alcohol and viscosity progressed southward. Bitterness was primarily affected by inland-coastal influence. The regional differentiation of astringency and bitterness introduced an orthogonal reading (N north- S south vs. E inland-W coastal, respectively), rather than a linear one, these findings adding novelty to sensory research. Additionally, several Portuguese-related studies were reviewed, and their findings were correlated with six sensory measures. Bioclimatic indexes, pH and the total phenol index were considered the strongest profilers in a nationwide assessment on red wine typicality. The ratio of the oligomeric/polymeric composition of tannins, as well as total anthocyanins, was also to be considered to be a valid sensory profiler. Several nationwide tendencies and correlations between sensory evaluations and wine chemistry may represent interesting findings and challenge unexplored ways for new researc

Interactions between wine phenolic compounds and human saliva in astringency perception

[EN] Astringency is a complex perceptual phenomenon involving several sensations that are perceived simultaneously. The mechanism leading to these sensations has been thoroughly and controversially discussed in the literature and it is still not well understood since there are many contributing factors. Although we are still far from elucidating the mechanisms whereby astringency develops, the interaction between phenolic compounds and proteins (from saliva, oral mucosa or cells) seems to be most important. This review summarizes the recent trends in the protein–phenol interaction, focusing on the effect of the structure of the phenolic compound on the interaction with salivary proteins and on methodologies based on these interactions to determine astringency

Effect of the harvest season on phenolic composition and oenological parameters of grapes and wines cv. Touriga Nacional (Vitis vinifera L.) produced under tropical semi-arid climate, in the state of Pernambuco, Brazil

The northeastern region of São Francisco Valley is the third largest wine producer in Brazil, differentiated by the production of at least two harvests per year, generally in the first and second semesters, respectively. The productive cycle of the vine in the first semester is higher than in the second semester, mainly due to differences in temperature, with maximum and average temperatures of approximately 30 ºC and 26 ºC, respectively. Second semester is characterized by higher temperatures (summer season) and that promote a rapid maturation of the grapes. The objective of this work was to evaluate the phenolic composition, other oenological parameters and the sensorial profile of grapes and wines of cv. 'Touriga Nacional' (Vitis vinifera L.), characterizing grapes and wines from four harvest seasons, two of them referring to the first half of the year and two referring to the second half of the year, using a broad analytical approach. The experimental design consisted of three randomized blocks, with sixty plants marked in different lines and positions (twenty plants in each block at the beginning, middle and end of the vineyard). The results showed that there was a harvesting effect for some of the grape chemical compounds (monomeric anthocyanins, organic acids, condensed tannins and monomeric flavanols, for example) as well as in wines (calcium, monomeric anthocyanins, condensed tannins and monomeric flavanols). Regarding the sensorial profile of the wines, it was possible to observe that higher scores were attributed to floral aroma in wines from the first harvest (first half of the year). Fruity, spice and empyreumatic aromas were higher in wines from second harvest season (second half of the year). For other attributes, there was a tendency for higher variations between the period of study (2014 – 2017) than between the harvest seasonsinfo:eu-repo/semantics/publishedVersio

Proyecto de gestión pedagógica para el desarrollo organizacional integral del Colegio Pedro Apóstol de la comuna de Puente Alto

Tesis (Magíster en Gestión Pedagógica y Curricular)La educación, en la sociedad de conocimiento, requiere de procesos multidisciplinarios y de la integridad de todas sus dimensiones, para responder a las exigencias de la sociedad moderna y a las necesidades del hombre de hoy. En este sentido, la educación debe formar a las personas para que sean competentes, capaces de asumir los retos del mundo contemporáneo con toda su complejidad; además, lograr una educación de calidad, igualitaria, equitativa y pertinente. La educación es un fenómeno complejo. Se requiere que toda la comunidad se involucre en su proceso, con el propósito de formar personas íntegras. Sin embargo, este sublime propósito no ha sido suficientemente alcanzado, ya que el sistema educacional nacional sigue siendo un proceso segregado y tradicional, sin tener una visión común, y no se visualiza como un sistema. En el nivel local o establecimiento escolar, los problemas de educación se manifiestan en el divorcio entre los procesos organizacionales y los procesos de gestión pedagógica. ¿Cómo se gestiona para que estos procesos se desarrollen de manera integral? Este proyecto de Gestión Pedagógica para el desarrollo organizacional integral con un enfoque educativo del Colegio Pedro Apóstol de la comuna de Puente Ato, fue construido de manera endógena, es decir, con la participación de los integrantes del establecimiento en los procesos de recopilación de datos, por medio de métodos de investigación histórico documental institucional y métodos de recopilación de datos para detectar las necesidades de la institución. Este proyecto es relevante ya que responde a la necesidad del Colegio para desarrollar todo el proceso de gestión integral como palanca de transformación para lograr su objetivo común que es la educación para la vida

Wine pH Prevails over Buffering Capacity of Human Saliva

Wine is an acidic beverage; its pH (2.9-3.8) is critically important to its organoleptic properties. During degustation, wine interacts with <1 mL of mouth saliva, the pH of which is near 7.0. This is buffered predominantly by the carbonate/bicarbonate pair (pK(a) = 6.1). Few data are available on whether the buffering capacity of saliva may alter the pH of wine and thus its sensorial properties. In this study both in vitro and in vivo approaches were conducted to measure pH in mixtures of representative red and white wines with human saliva. Continuous additions of microvolumes of either wine to a definite volume (3 mL) of saliva in vitro resulted in a progressive and steep decline in the pH of the wine/saliva mixture. Thus, a few microliters of either wine (<0.27 mL) was sufficient to reduce the pH of saliva by 1 pH unit. Further additions of wine to saliva lowered the pH to that of the corresponding wine. In the in vivo assay, definite volumes (1.5-18 mL) of either wine were mixed for 15 s with the mouth saliva of individual healthy subjects before pH determination in the expectorated wine/saliva mixtures. Compared to saliva, pronounced decreases in pH were observed, thus approaching the pH of wine even with the smallest volume of wine in the assay. Altogether, these results demonstrate that the buffering capacity of wine prevails over that of saliva and that during degustation the pH of the wine/saliva mixture in the mouth is, at least temporarily, that of the corresponding wine.Fondecyt-Chile 115024