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IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 ´Vinho Verde´ wines production from differential fermentation: the role of musts sulphitation as a preservation strategy to keep the musts character

´Vinho Verde´ wines production from differential fermentation: the role of musts sulphitation as a preservation strategy to keep the musts character

Abstract

High-volume mass-market white wines production method by means of harvest-deferred fermentation from desulphited musts allows an efficient business management by avoiding the seasonality in wine sector. This technology has been used in the production of light and fresh wines from Vinhos Verdes Appellation (VVA – Portugal). This Appellation presents a diversity of varieties and wine styles, and is known for producing light and fresh wines, but also mineral, complex and structured ones, with, in general, low ethanol content. The light and fresh VV wines are characterized by herbaceous, citrus, tropical fruits, orchard fruits and floral notes. Thus, the goal of this work was to unveil based on physical-chemical data if sulphitated musts from VVA preserve the organoleptic potential that allows the production of high-volume wines with the typical light and fresh VV character. A set of musts were produced at industrial scale from grapes harvested from different sub-regions of VVA, which were then sulphited and stored for 1 year. For comparison purpose, sulphitated musts from Beira Atlântico and Trás-os-Montes Portuguese regions were also characterized. Free volatile and glycosidically-linked compounds were determined by advanced gas chromatography (GC×GC-ToFMS). The physical-chemical parameters currently used in musts quality control were also determined. Statistical tools were applied by combining all data domains. The aroma potential of musts was performed based on the construction of aroma networks [1].A total of 145 volatile compounds were putative identified, which varied from 136 to 142, in must from Cávado and Lima sub-regions, respectively. Regarding the glycosidically-linked fraction, 29 compounds were putatively identified, which varied from 20 to 24 in must from Cávado and Amarante sub-regions. Clustering analysis unveiled the formation of 3 main clusters, one of which includes all VVA musts, which allows to infer that geographical region is the main distinguishing factor. VVA musts were characterized with higher total acidity, and lower °Brix, potency alcoholic strength and density, compared with the samples from other regions. Moreover, esters, monoterpenic and sesquiterpenic compounds detected in VVA musts may contribute with citrus, floral, orchard and tropical fruits aromas, which are relevant aromas for sensory characteristics of VV wines. Thus, must sulphitation, a methodology used to extend its preservation beyond the harvest season, seems to keep the particular musts character, which is extremely important for the consistency of light and fresh high-volume VV wines.

Acknowledgments:

This work was funded under the project PRECIDIF – Precision Management of new Vinho Verde wines production from differential fermentation, project nº 24214. FCT/MEC for financial support LAQV-REQUIMTE (UIDB/50006/2020) through national funds and co-financed by the FEDER and PT2020.

References

[1] Y-Y Ahn, SE Ahnert, JP Bagrow, A-L Barabási, Flavor network and the principles of food pairing, Scientific reports (2011) 1, 196.

DOI:

Publication date: June 24, 2022

Issue: IVAS 2022

Type: Poster

Authors

Rocha Silvia1, Martins Cátia1, Fontes Natacha2, Cunha e Silva Sara2 and Graça António2

1LAQV-REQUIMTE & Department of Chemistry, University of Aveiro
2Sogrape Vinhos, S.A.

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Keywords

white must sulphitation; free volatile compounds; glycosidically-linked compounds; physical-chemical parameters; aroma potential

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IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 ´Vinho Verde´ wines production from differential fermentation: the role of musts sulphitation as a preservation strategy to keep the musts character

´Vinho Verde´ wines production from differential fermentation: the role of musts sulphitation as a preservation strategy to keep the musts character

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IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 ´Vinho Verde´ wines production from differential fermentation: the role of musts sulphitation as a preservation strategy to keep the musts character

´Vinho Verde´ wines production from differential fermentation: the role of musts sulphitation as a preservation strategy to keep the musts character

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Publication date: June 24, 2022

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Postveraison shoot trimming in Tannat and Merlot: preliminary results on yield components, plant balance and berry composition

There is currently a trend towards the production of wines with low alcohol content. To achieve this, grapes with low sugar content must be used. There are techniques at the vineyard level that can delay ripening and avoid excessive sugar accumulation without, a priori, affecting the final polyphenol content. Postveraison shoot trimming (PVST) is experimentally evaluated for these purposes, but its impact under Uruguayan climatic conditions with high interannual variability is not known. The aim of this work is to assess the PVST in Tannat and Merlot cultivars and their impact on yield components, plant balance and berry primary composition. In this study, two commercial vineyards of 10 years old Tannat and Merlot (grafted on SO4) at Canelones Department were selected. During the 2020-201 growing season, grapevines were submitted to PVST when grapes reached 15º Brix. In a randomized block, trimmed (T) and control (C) plants were evaluated with three repetitions each cultivar. Evaluation of the evolution of primary berry composition during ripening, measurement of yield components and plant balance were performed. For both cultivars, PVST did not affect yield components. Merlot reached 5.4 kg per plant and Tannat 7.1 kg, with not statistical significance between treatments. However, statistical differences were observed in terms of plant balance. In Merlot Ravaz Index reached a difference of 5.3 (12.0 in T and 6.7 in C) meanwhile Tannat reached 3.5 of statistical difference (13.7 in T and 10.2 in C). The tendency to imbalance for the treated plants had an impact on the final grape composition. Merlot grapes showed statistical difference in final total acidity (0.3 g of difference between treatments) while treatments impact final sugar content on Tannat grapes (10.0 g of difference between treatments). Further studies are needed to assess the impact of different canopy management techniques in our conditions.

Heatwaves and grapevine yield in the Douro region, crop model simulations

Heatwaves or extreme heat events can be particularly harmful to agriculture. Grapevines grown in the Douro winemaking region are particularly exposed to this threat, due to the specificities of the already warm and dry climatic conditions. Furthermore, climate change simulations point to an increase in the frequency of occurrence of these extreme heat events, therefore posing a major challenge to winegrowers in the Mediterranean type climates. The current study focuses on the application of the STICS crop model to assess the potential impacts of heatwaves in grapevine yields over the Douro valley winemaking region. For this purpose, STICS was applied to grapevines using high-resolution weather, soil and terrain datasets over the Douro. To assess the impact of heatwaves, the weather dataset (1989-2005) was artificially modified, generating periods with anomalously high temperatures (+5 ºC), at certain onset dates and with specific durations (from 5 to 9 days). The model was run with this modified weather dataset and results were compared to the original unmodified runs. The results show that heatwaves can have a very strong impact on grapevine yields, strongly depending on the onset dates and duration of the heatwaves. The highest negative impacts may result in a decrease in the yield by up to -35% in some regions. Despite some uncertainties inherent to the current modelling assessment, the present study highlights the negative impacts of heatwaves on viticultural yields in the Douro region, which is critical information for stakeholders within the winemaking sector for planning suitable adaptation measures.

Spatiotemporal patterns of chemical attributes in Vitis vinifera L. cv. Cabernet Sauvignon vineyards in Central California

Spatial variability of vine productivity in winegrapes is important to characterise as both yield and quality are relevant for the production of different wine styles and products. The objectives were to understand how patterns of variability of Cabernet Sauvignon fruit composition changed over time and space, how these patterns could be characterised with indirect measurements, and how spatial patterns of the variation in fruit compositional attributes can aid in improving management. Prior to the 2017 vintage, 125 data vines were distributed across each of four vineyards in the Lodi American Viticultural Area (AVA) of California. Each data vine was sampled at commercial harvest in 2017, 2018, and 2019. Yield components and fruit composition were measured at harvest for each data vine, and maps of yield and fruit composition were produced for eight ‘objective measures of fruit quality’: total anthocyanins, polymeric tannins, quercetin glycosides, malic acid, yeast assimilable nitrogen, β-damascenone, C6 alcohols and aldehydes, and 3-isobutyl-2-methoxypyrazine. Patterns of variation in anthocyanins and phenolic compounds were found to be most stable over time. Given this relative stability, management decisions focused on fruit quality could be based on zonal descriptions of anthocyanins or phenolics to increase profitability in some vineyards. In each vineyard, dormant season pruning weights and soil cores were collected at each location, elevation and soil apparent electrical conductivity surveys were completed, and remotely sensed imagery was captured by fixed wing aircraft and two satellite platforms at major phenological stages. The data collected were used to develop relationships among biophysical data, soil, imagery, and fruit composition. The standardised and aggregated samples from four vineyards over three seasons were included in the estimation of ‘common variograms’ to assess how this technique could aid growers in producing geostatistically rigorous maps of fruit composition variability without cumbersome, single season sampling efforts.