Les justifications “terroirs” en terme de marketing: les conditions sont réunies pour une rencontre de qualité entre le consommateur moderne et le vin

Currently, climate change represents one of the major issues for the wine sector. The increasing temperature already recorded and expected in the upcoming years reduce the vegetative cycle of the grape varieties planted in Bordeaux area, affecting the physicochemical parameters of grapes and consequently, the quality of wine. From a sensory point of view, the attenuation of the fresh fruity character in some varietals is accompanied by the accentuation of dried-fruit notes [1]. As a new adaptive and ecological strategy on global warming, some winegrowers have initiated changes in the Bordeaux blend of vine varieties using late-ripening grape varieties [2]. 

Grape pomace is one of the main by-products generated after pressing in wine-making. It’s valorization through the extraction of bioactive compounds is the answer for the development of sustainable processes. Nevertheless, in the recovery of anthocyanins derivatives, the extraction stage continues to be a limiting step. The nature of the sample and the type of solvent determine the efficiency of the process

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

For the first time, it was established that the timing of inoculation with LAB could significantly impact the concentration of many secondary metabolites leading to significant aromatic changes. From studied compounds, the most influenced were esters and diacetyl.

Accumulation of anthocyanins (Anth) on whole winegrape (Vitis vinifera L.) bunches attached to the vine was monitored by a fluorescence-based sensor (Multiplex) on ‘Aleatico’ and ‘Nero d’Avola’. Different water regimes were applied.