 IVES 9 IVES Conference Series 9 Macrowine 9 Macrowine 2021 9 Grapevine diversity and viticultural practices for sustainable grape growing 9 Evolution of grape aromatic composition in cv. Ugni blanc

Evolution of grape aromatic composition in cv. Ugni blanc

Abstract

AIM: Cognac is a protected appellation of origin where world-famous brandies are produced. These brandies are obtained by the traditional double distillation of wines from Ugni blanc cultivar, which is the main variety planted. According to the Cognac Appellation, harvest can occur between 13 & 21 °Brix. To date the harvest is assessed by vine growers only by sugar & acidity ripeness without considering the evolution of the aromatic profile. Hence, the goal of this research is to study the behavior of the main volatile compounds of grapes in order to better conduct the harvest.

METHODS: Two vineyard plots during two consecutive vintages (2019, 2020) were used to collect different fractions of 30 whole bunches. The samples were collected every week from pea-size to over ripeness (>21 °Brix) and then were stored at – 40°C until further analysis. Berries were grounded according to the protocol as described in Poitou, 2016. Grape powder were obtained and then analyzed for free & total volatiles by SPME-GC/MS (Young et al. 2015 ; Poitou, 2016). Principal component analysis (PCA) was conducted on the means of all significantly different parameters to elucidate the differences between grapes according to the maturity stage (Agilent MassProfiler Pro).

RESULTS: The kinetics of the volatile compounds during maturation showed strong variations with multiple trends depending the stage. Linear increase (e.g β-damascenone) or decrease (e.g p-cymene) of volatiles and a peak for cis-3-hexenol at véraison were found. Similarly to previous studies (Poitou, 2016 ; Ferrari et al. 2012), aromatic compounds were found to exhibit the same pattern. According to Rosillo et al. 1999, Ugni blanc & Chardonnay presents similar aromatic properties with low concentration of monoterpenes. Finally, the analysis of total volatiles showed the presence of newly identified terpenes in Ugni blanc grapes.

CONCLUSION

These results gave new insights for Ugni blanc aromatic characterization. Identification of terpenes with the total volatile method concludes that they are in their glycosylated form in grapes. Thus, they may be released during fermentation or distillation and participate to the aromatic complexity of wine distillates. With climate change, sugar concentration is expected to increase and will decouple sugar/acidity balance and the aromatic maturity. Therefore, understanding the aromatic maturity of Ugni Blanc will help growers to adapt their harvest date.

DOI:

Publication date: September 2, 2021

Issue: Macrowine 2021

Type: Article

Authors

Amandine Bernier

Jas Hennessy & Co, rue de la Richonne – CS20020, 16101 Cognac Cedex, France,Julia, GOUOT, Unité de recherche Œnologie, EA 4577, USC 1366 INRA, ISVV, Université de Bordeaux, F33882 Villenave d’Ornon, France Adeline, BARREAU, Jas Hennessy & Co, rue de la Richonne – CS20020, 16101 Cognac Cedex, France Panagiotis, STAMATOPOULOS, Jas Hennessy & Co, rue de la Richonne – CS20020, 16101 Cognac Cedex, France Xavier POITOU, Jas Hennessy & Co, rue de la Richonne – CS20020, 16101 Cognac Cedex, France

Contact the author

Keywords

aromatic potential, berry composition, maturity, ugni blanc

Citation

Using elicitors in different grape varieties. Effect over their phenolic composition

Phenolic compounds are very important in crop plants and have been the subject of a large number of studies. Three main reasons can be cited for optimizing the level of phenolic compounds in crop plants: their physiological role in plants, their technological significance for food processing, and their nutritional characteristics1 Indeed, an enormous diversity of phenolic antioxidants is found in fruits and vegetables, and their presence and roles can be affected or modified by several pre- and postharvest cultural practices and/or food processing technologies (Ruiz-García et al. 2012, Goldman et al. 1999, Tudela et al. 2002). In winegrapes, the technological importance of phenolic compounds, mainly flavonoids, is well-known.

Feasibility of pre-fermentative oenological tannins addition to enhance volatile composition and aroma perception in white wines

Oenological tannins (OETs) are an alternative to sulphur dioxide due to their antioxidant and antioxidase properties in the early phase of winemaking [1,2].

Applicability of grape native yeasts to enhance regional wine typicity

The universalization in wine production has been restricting the imprint of terroir in regional wines, resulting in loss of typicity. Microbes are the main driving force in wine production, conducting fermentation and originating a myriad of metabolites that underly wine aroma. Grape berries harbor an ecological niche composed of filamentous fungi, yeasts and bacteria, which are influenced by the ripening stage, cultivar and region. The research project GrapeMicrobiota gathers a consortium from University of Zaragoza, University of Minho and University of Tours and aims at the isolation of native yeast strains from berries of the wine region Douro, UNESCO World Heritage, towards the production of wines that stand out in the market for their authenticity and for reflecting their region of origin in their aroma.

Preliminary field studies of resistance of Georgian grapevine germplasm to powdery mildew (Erysiphe necator)

Erysiphe necator Schwein is a fungus that causes grapevine powdery mildew. It is one of the most problematic pathogens attacking Vitis vinifera L. The pathogen infects all green parts of the plant and reduces grape yield and quality. The suppression on mildew-susceptible cultivars requires intensive use of fungicides against pathogen, which has negative impact on the environment and human health.

Integrated approach to grape stalks valorization: sustainable recovery of bioactive compounds and biofuel production

Grape stalks are a byproduct of the winemaking process and represent a valuable and inexpensive source of bioactive compounds. While their direct use in whole bunch fermentation is known, the majority of grape stalks are discarded, posing environmental and economic challenges.