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Effect of Micro-oxygenation on Color and Anthocyanin-Related Compounds of Wines with Different Phenolic ContentsFigure 5. Development of WC, WCP, and CRDSO2 in W1, W2, and W3 wines (±SD). Each point correspondsto t 0, t 1, t 2, and t 3.the newly formed pigments, for example, ethyllinkedpigments, since the absorbance of these molecules at620 nm is higher than that of genuine anthocyanins(the percentage of blue color in MO wines was higherthan in control wines).Pyranoanthocyanins also may have participated inthe higher CI as they show both higher absorbanceat 420 nm and contribute to the redness of wines. Thehue evolved in a very similar way in all the wines, witha tendency to increase, but more so in control wine,demonstrating that no detectable browning occurredin the MO wines.Figure 5 reflects the evolution of WC, WCP, and CRD-SO 2. A very small decrease in WC was observed in allwines with no differences due to MO. WCP decreasedwith time, and the decreases were concomitant withthe loss of free anthocyanins usually observed duringwine evolution, meaning that the formation of anthocyanin-derivedpigments did not compensate for freeanthocyanin degradation.Figure 6. Development of abs280 and tannins indifferent wines (±SD). Each point corresponds to t 0,t 1, t 2, and t 3.A continuous increase in pigments resistant to SO 2bleaching was observed. The formation of pyranoanthocyanins,which are very stable compounds toward98
Seminario TécnicoCompuestos azufrados volátiles en vinosWith regard to optical density and tannin content (Figure6) and mean degree of polymerization (mDP) (Figure7), no changes in abs280 were detected in any ofthe wines, indicating the absence of significant winepigment precipitation. As regards tannins, their levelsdecreased during MLF in W2 and W3, but since nodecrease in abs280 was detected, this phenomenonwas probably due to tannins breaking down to givesmall structures that were not detected by the BSAmethod. Similar values for the control and MO wineswere observed at t2. From t2 to t3, the concentrationbarely changed, although MO wines showed a slightlyhigher tannin content.Figure 7. Development of mean degree ofpolymerization of tannins in W1, W2, and W3 wines(±SD). Each point corresponds to t 0, t 1, t 2, and t 3.Figure 8. Graphical plot representing thedistribution of the wine samples in the planedefined by principal components 1 and 2 asregards their chromatic characteristics (MO wines:solid symbols; control wines: open symbols; W1:circles; W2: squares; and W3: triangles). Thevariance explained by each principal component isshown in parentheses.SO 2and pH due to the substitution of C4 (47), wasprobably associated with this evolution. Ethyl-linkedcompounds also should be resistant to sulfite additionand may have contributed to the observed changes,explaining as to why the values were higher inMO wines.Different behavior with regard to mDP was observedfor the different wines. This parameter always increasedin the first period (from t0 to t1) for all wines and thenfell, except for W1. According to Nikfardjam and Dykes(53), this increase corresponds to the wine structuringphase described in empirical observations (13), and thisphase appears to occur irrespective of whether oxygenis being dosed into the wine. The reduction of mDP observedafterward, mainly in W2 (MO) and W3 (MO), maybe due to a possible structural rearrangement of thetannins to shorter forms, which would correlate withthe small decreases observed in the tannins measuredby the BSA method. This reduction in mDP may be responsiblefor a reduction in wine astringency (54, 55).The interaction of these newly formed intermediateswith anthocyanins also may reduce astringency sincethey can form terminal units of these shorter forms,preventing further polymerization (56). The differentbehavior of W1 (MO) was similar to that described byDu Toit et al. (57) when MO was applied to a wine fortoo long a period of time. It seems that W1 could havesuffered overoxygenation in the MO wine, and therefore,an increase of mDP was observed.Multivariate statistical analysis was used in this studyto check as to whether the wines could be groupedaccording to the variables studied. First, a clusteranalysis was conducted using all the studied variablessince this is a powerful visualization tool that enablesgroupings to be observed within the data. This is anunsupervised method for pattern recognition, wherethe samples were clustered without prior knowledgeof their belonging to any wine type. The distance matrixwas calculated using square Euclidean distancesand an average linkage method algorithm. Distancemeasures the similarity or dissimilarity between thedifferent samples. Two clearly differentiated clusterswere found (data shown in Supporting Information).In one of them we found W1, both control and MO wines,and W2 (C), showing that W1 (C) and W2 (C) werequite close. W2 (MO) was classified as closer to the W3wines. In the case of W2, it seems that MO originatedthe maximum differences in the wine characteristics.MO promoted changes in its phenolic structure, leadingto a wine with chromatic characteristics closer toa wine with a higher phenolic content.Textos asociados99
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Organizan:Seminario TécnicoCompues
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Seminario TécnicoCompuestos azufra
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01. Relación entre el contenido ni
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02. Los nuevos retosen microbiolog
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02. Los nuevos retos en microbiolog
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03. La microoxigenaciónde vinos ti
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03. La micro-oxigenación de vinos
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03. La micro-oxigenación de vinos
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04. ¡Los compuestosvolátiles no s
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04. ¡Los compuestos volátiles no
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04. ¡Los compuestos volátiles no
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Influence of the Timing of Nitrogen
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Page 48 and 49: Influence of the Timing of Nitrogen
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Page 52 and 53: Formación de compuestos volátiles
Page 58 and 59: CapítuloSpiropoulos A, Tanaka J, F
Page 60 and 61: Una revolución en el sector enólo
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Page 65 and 66: article, when we consider the fl av
Page 67 and 68: y lowering higher alcohols producti
Page 69 and 70: colour composition. Analytical para
Page 71: 21 Henschke, P.A.; Jiranek, V. (199
Page 74 and 75: Unravelling the genetic blueprint o
Page 77 and 78: When the heat is on,yeast fermentat
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Page 84 and 85: Taking control of alcoholEthanol [%
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Page 106 and 107: CapítuloSISTEMADEALIMENTACIÓNBOMB
Page 108 and 109: CapítuloGráfico 4.- Evolución de
Page 110: Capítulo(20) Es-Safin.E, Fulcrand
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