RT Journal Article
SR Electronic
T1 Effect of Winery Yeast Lees on Touriga Nacional Red Wine Color and Tannin Evolution
JF American Journal of Enology and Viticulture
JO Am. J. Enol. Vitic.
FD American Society for Enology and Viticulture
SP ajev.2012.11103
DO 10.5344/ajev.2012.11103
A1 Ana Rodrigues
A1 Jorge Manuel Ricardo-Da-Silva
A1 Carlos Lucas
A1 Olga Laureano
YR 2012
UL http://www.ajevonline.org/content/early/2012/10/04/ajev.2012.11103.abstract
AB Red wine aging on lees is a winemaking practice used to achieve more rounded and less astringent resulting wines. In the present work the effect of adding two different winery external yeast lees to a red wine on its color and tannin evolution during earlier stage of aging was studied. The results indicated that the yeast lees addition did not show an effect on color stabilization, during the studied period of time. Both color compounds and condensed tannins were quickly adsorbed to the yeast lees at the beginning of the experiment. There was a retarding effect on the proanthocyanidin polymerization reaction by the addition of yeast lees, leading to the maintenance of the low and medium size tannins in solution. Thus, it was observed two different interactions: first, the proanthocyanidin adsorption by the yeast lees, namely the ones with the highest polymerization degree and second, the retarding of proanthocyanidin polymerization probably by the yeast lees released mannoproteins. The yeast lees age was a conditioning factor in the mannoprotein release and on its effect in wine.