Genetic traceability of ‘Nebbiolo’ musts and wines by single nucleotide polymorphism (SNP) genotyping assays

AIM Aiming to explore the possibility of shortening red winemaking maceration times (1,2), this study presents the effect of the application of high-power ultrasounds to crushed grapes, at winery-scale, on the content of varietal volatile compounds (free and glycosidically-bound) in musts and on the overall aroma of wines.

The objective of the present work is to assess yeast effects on the development of wine varietal aroma throughout aging and on wine longevity.

Three independent experiments were carried out; two fermenting semi-synthetic musts fortified with polyphenols and aroma precursors extracted from Tempranillo (1) or Albariño (2) grapes and with synthetic precursors of polyfunctional mercaptans (PFMs), and a third in which a must, mixture of 6 different grape varieties was used. In all cases, fermentations were carried out by different Saccharomyces cerevisiae strains and one S. kudriavzevii, and the obtained wines were further submitted to anoxic accelerated aging to reproduce bottle aging. The volatile profile of the wines was analyzed using several chromatographic procedures, in order to provide a comprehensive evaluation of wine aroma. Aroma compounds analyzed included fermentation volatile metabolites, grape-derived aroma compounds including PFMs, and Strecker aldehydes (SA).

Results revealed that the effects of yeast on wine aroma throughout its self-life extend along three main axes:

1. A direct or indirect action on primary varietal aroma and on its evolution during wine
aging.

2. The direct production of SA during fermentation and/or their delayed formation by producing the required reagents (amino acids + dicarbonyls) for Strecker degradation
during anoxic aging.

3. Producing acids (leucidic, branched acids) precursors to fruity esters. More specifically, and leaving aside the infrequent de novo formation, the action of the different strains of yeast on primary varietal aroma takes four different forms:

1.- Speeding the hydrolysis of aroma precursors, which leads to early aroma formation without changing the amount of aroma formed. In the case of labile molecules, such as linalool, the enhancement of young wine aroma implies a short-living wine. 2.- Metabolizing the aroma precursor, reducing the amounts of aroma formed, which can be of advantage for negative aroma compounds, such as TDN or guaiacol; 3.- Transforming grape components into aroma precursors, increasing the amounts of aroma formed, as for ethyl cinnamate, leucidic acid or vinylphenols; 4.- Forming reactive species such as vinylphenols able to destroy varietal polyfunctional mercaptans.

Overall, it can be concluded that the yeast carrying alcoholic fermentation not only influences fermentative wine aroma but also affects to the wine varietal aroma, to its evolution during aging and to the development of oxidative off-odors

La qualité des vins dépend de différents facteurs et procédés, notamment de la nature des terrains viticoles. Dans ce travail, nous avons cherché à établir les liens entre descripteurs pédologiques des parcelles et descripteurs sensoriels des vins. Sur la base de Classifications Ascendantes Hiérarchiques (CAH) et d’Analyses en Composante Principale (ACP), il a été possible d’établir des liens entre la nature des parcelles (sableuse, argileuse, sablo-graveuleuse) et certains descripteurs sensoriels des vins (chaleur, astringence, fruit noir) et plus globalement avec le type de vins élaborés.

Many vineyards implanted in Brazil in the last 20 years are placed under very different natural conditions if compared to Serra Gaúcha, the oldest and more traditional viticultural region in the country.

Sulphur dioxide has long been considered an irreplaceable additive due to its numerous significant positive effects during winemaking and beyond.