Montevideo, Uruguay
Montevideo, Uruguay

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Boido E.,Seccion Enologia | Farina L.,Seccion Enologia | Carrau F.,Seccion Enologia | Dellacassa E.,Seccion Enologia | Cozzolino D.,The Australian Wine Research Institute
Food Analytical Methods | Year: 2013

The objective measure of grape quality is an important requirement to enhance wine quality. Particularly, the quantitation of glycosylated aroma compounds could be a useful index for winemakers. In the present work, we evaluated the bound compounds profile on Tannat grapes, and the potential of near infrared (NIR) spectroscopy coupled to chemometric techniques to determine the concentration of the different glycosylated aroma compounds present in this grape variety. The results showed phenols and norisoprenoids as the quantitative most important group of compounds, representing almost 80 % of the total glycosidic components present in Tannat grapes. The glycosidic form of ethyl-β-(4-hydroxy-3-methoxy-phenyl)-propionate was identified for the first time in grapes. The results suggested NIR technique as a screening tool for a fast analysis of the grape aroma potential. The application of such methodology would be ideal for fast grape screening purposes, contributing to the winemaking decisions, classification of the fruit, and perhaps maturity monitoring. © 2012 Springer Science+Business Media, LLC.

Boido E.,Seccion Enologia | Garcia-Marino M.,University of Salamanca | Dellacassa E.,Catedra de Farmacognosia y Productos Naturales | Carrau F.,Seccion Enologia | And 2 more authors.
Australian Journal of Grape and Wine Research | Year: 2011

Background and Aims: Changes in different polyphenol families during grape ripening and vinification were determined in Tannat grapes. This was done to establish a polyphenol profile for Tannat grapes during ripening and for young wines. Methods and Results: We demonstrated, by high-performance liquid chromatography with diode array detection and mass spectrometry (HPLC-DAD-MS) analysis, that the content of flavan-3-ols in Tannat seeds was higher than that reported for a large number of other grape varieties analysed. Forty percent of the total flavan-3-ols in seeds were galloylated compounds, whereas the flavan-3-ol profile in skins was characterised by the absence of galloylated forms. Prodelphinidins in skins ranged between 30 and 35% with very low values for epigallocatechin. Epicatechin gallate was not detected in Tannat wine and galloylated forms represented a low percentage of total flavan-3-ols. Tannat grapes had very high concentrations of anthocyanins in skins with levels increasing during ripening. Eleven phenolic acids were identified in Tannat grape skins and wines, but only gallic and protocatechuic acids were found in the seeds. Conclusions: Tannat wines were shown to have one of the highest levels of phenolic compounds reported for vinifera grape varieties. The profiles for different polyphenol families present in Tannat grapes (skins and seeds) and wines were determined. Significance of the Study: The results presented will help to better understand the phenolic winemaking potential of this variety and its functional properties within food chemistry. © 2011 Australian Society of Viticulture and Oenology Inc.

Gonzalez-Pombo P.,Catedra de Bioquimica | Farina L.,Seccion Enologia | Carrau F.,Seccion Enologia | Batista-Viera F.,Catedra de Bioquimica | Brena B.M.,Catedra de Bioquimica
Food Chemistry | Year: 2014

A major fraction of monoterpenes and norisoprenoids in young wines is conjugated to sugars representing a significant reservoir of aromatic precursors. To promote their release, b-glucosidase, a-arabinosidase, and α-rhamnosidase from a commercial Aspergillus niger preparation, were immobilized onto acrylic beads. The aim of this work was the development and application of an immobilized biocatalyst, due to the well-known advantages over soluble enzyme preparations: control of the reaction progress and preparation of enzyme-free products. In addition, the obtained derivative showed increased stability in simile wine conditions. After the treatment of Muscat wine with the biocatalyst for 20 days, free monoterpenes increased significantly (from 1119 to 2132 μg/L, p < 0.01) with respect to the control wine. Geraniol was increased 3,4-fold over its flavor thresholds, and accordingly its impact on sensorial properties was very relevant: nine of ten judges considered treated wine more intense in fruit and floral notes. © 2013 Elsevier Ltd.

Gonzalez-Pombo P.,Catedra de Bioquimica | Farina L.,Seccion Enologia | Carrau F.,Seccion Enologia | Batista-Viera F.,Catedra de Bioquimica | Brena B.M.,Catedra de Bioquimica
Process Biochemistry | Year: 2011

Since most Saccharomyces strains show no β-glucosidase activity, the importance of non-Saccharomyces β-glucosidases in the development of wine aroma has been highlighted. However, only a few enzymes from yeasts isolated from grape-must and enological ecosystems are active in the stringent conditions of wine and the wine-making process (low pH, high concentrations of ethanol or glucose). A purified extract of extracellular β-glucosidase from Issatchenkia terricola, proved to be very active in the presence of glucose (100 g/L), ethanol (18%) and metabisulfite (60 mg/L). It is also active and relatively stable at acidic pH over 3.0. Immobilization onto Eupergit C greatly improved its stability, allowing the aromatization of white Muscat wine over a 16-day experiment. The released aroma compounds of control and treated wine were analyzed by GC-MS. The enzymatic treatment significantly increased the amount of monoterpenes and norisoprenoids, showing the potential of the immobilized enzyme for aroma development in wines. © 2010 Elsevier Ltd. All rights reserved.

Coniberti A.,Instituto Nacional Of Investigacion Agropecuaria | Ferrari V.,Instituto Nacional Of Investigacion Agropecuaria | Dellacassa E.,Seccion Enologia | Boido E.,Seccion Enologia | And 3 more authors.
European Journal of Agronomy | Year: 2013

Under humid climatic conditions, crop loss due to bunch rot can be as high as 100% in a given year and, in many cases, it becomes the main factor determining harvest. Although the effectiveness of fruit zone leaf removal depends on initial fruit microclimate, it is generally extremely effective at reducing bunch rots. The impact of leaf removal on Sauvignon blanc must composition and wine sensory attributes, is in general considered detrimental. High temperature achieved as a result of excessive bunch exposure may negatively affect primary and secondary grape metabolites responsible for its typical wine style. The main objective of this work was to determine, if kaolin application over clusters, reduce sunburn and other berry damage associated with excessive fruit exposure. Three treatments were evaluated: untreated control (C); fruit zone leaf removal (LR); and fruit zone leaf removal plus kaolin application (LR. +. K). Kaolin application significantly reduced berry temperature, sunburn and other berry damage associated with excessive fruit exposure. Wines from the LR. +. K treatment had the highest sensory scores of all three treatments and were related more to a high intensity of fruity and tropical notes rather than to the absence of green notes as a consequence of leaf remova. © 2013 Elsevier B.V.

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