Macrowine 2021
IVES 9 IVES Conference Series 9 Ability of Saccharomyces cerevisiae strains to modulate the aroma of albariño wines

Ability of Saccharomyces cerevisiae strains to modulate the aroma of albariño wines

Abstract

The objective of the present work is to evaluate the impact of three S. cerevisiae strains on the comprehensive aroma profile of Albariño wine along its shelf life.

The strains Lalvin QA23TM, Lalvin SauvyTM and Affinity ECA5TM (Lallemand Bio) fermented a model must containing precursors of polyfunctional mercaptans (PFMs) and a polyphenolic and aroma precursor fraction1 extracted from Albariño grapes. Wines were submitted to accelerated anoxic aging at 50 ºC during 1, 2, 5, 8 weeks and at 75 ºC during 12, 24, 48, 72h of aging, respectively. Fermentative aroma compounds, SO2, Strecker aldehydes, and varietal aroma compounds were determined by GC, using six different analytical methods.

The aroma profiles of the Albariño wines obtained are characterized by low amounts of volatile phenols, vanillin derivatives and TDN precursors and by medium to high levels of linalool, β-damascenone, rose oxide, γ-nona and γ-decalactones, which explain the typical and subtle floral aroma notes associated with Albariño wines2. Levels of linalool faded during aging, but floral notes may be partially compensated by increasing levels of ethyl cinnamate.

The ability of the strains assayed to modulate levels of terpenes and lactones was limited citronellol and rose oxide. They were able to influence slightly but significantly levels of β-damascenone and ethyl cinnamate in aged wines. This suggests that the influence of the strains on floral notes is significant, but not dominant3. In clear contrast, the strains introduced a great variability in the levels of PFMs which mostly remained all along wine shelf life.

Even if aging was carried out under strict anoxic conditions, levels of Strecker aldehydes increased, isobutanal and 2-methylbutanal in a strain-dependent way, suggesting that Strecker degradation of amino acids took place with already present wine α-dicarbonyls. Levels of diacetyl and isovaleric acid increased during aging, in spite of the fact that aging conditions were not adequate for microbial development.

Regarding fermentative compounds, levels of higher alcohols and their acetates, straight and branched chain fatty acids and their ethyl esters as well as Strecker aldehydes were strongly strain-dependent. Except for acetates, differences were maintained during aging or even intensified in the cases of aldehydes and ethyl esters of branched acids.

Finally, aging at 50 and 75 ºC were in general very well correlated, suggesting that aging at 75ºC can satisfactorily predict evolution during aging of many wine components. aging at 75ºC can satisfactorily predict evolution during aging of many wine components, except PFMs and Strecker aldehydes.

S. cerevisiae strains can be used to produce Albariño wines with completely different sensory profiles and different sensory evolutions during aging. While the effects on varietal floral and sweet aroma compounds was just moderate, effects on PFMs and fermentative aroma compounds, including Strecker aldehydes were very large.

DOI:

Publication date: September 14, 2021

Issue: Macrowine 2021

Type: Article

Authors

Marie Denat 

Laboratory for Aroma Analysis and Enology (LAAE), University of Zaragoza, Instituto Agroalimentario de Aragón (IA2) (UNIZAR-CITA), Zaragoza (Spain)  ,Vicente FERREIRA, (LAAE), University of Zaragoza, Instituto Agroalimentario de Aragón (IA2), Zaragoza (Spain) Ignacio ONTAÑÓN, (LAAE), University of Zaragoza, Instituto Agroalimentario de Aragon (IA2), Zaragoza (Spain)

Contact the author

Keywords

cerevisiae, fermentation, wine aging, albariño, polyfunctional mercaptans, strecker aldehydes

Citation

Related articles…

Climate change projections to support the transition to climate-smart viticulture

The Earth’s system is undergoing major changes through a wide range of spatial and temporal scales as a response to growing anthropogenic radiative forcing, which is pushing the whole system far beyond its natural variability. Sources of greenhouse gases largely exceed their sinks, thus leading to a strengthened greenhouse effect. More energy is thereby being supplied to the system, with inevitable shifts in climatic patterns and weather regimes. Over the last decades, these modifications have been manifested in the full statistical distributions of the atmospheric variables, with dramatic changes in the frequency and intensity of extremes. Natural hazards, such as severe droughts, floods, forest fires, or heatwaves, are being triggered by extreme atmospheric events worldwide, thus threatening human activities. Viticultculture is not only exposed to changing climates but is also highly vulnerable, as grapevine phenology and physiological development are strongly controlled by atmospheric conditions. Therefore, the assessment of climate change projections for a given region is critical for climate change adaptation and risk reduction in viticulture. By adopting timely and suitable measures, the future sustainability and resiliency of the sector can be fostered. Climate-grapevine chain modelling is an essential tool for better planning and management. However, the accuracy of the resulting projections is limited by many uncertainties that must be duly taken into account when transferring knowledge to stakeholders and decision-makers. Climate-smart viticulture will comprise ensembles of locally tuned strategies, envisioning both adaptation and mitigation, assisted by emerging technologies and decision-support systems.

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.

Influence of agronomic practices in soil water content in mid-mountain vineyards

In the context of LIFE project MIDMACC (LIFE18 CCA/ES/001099), several pilots have been installed in vineyards in mid mountain areas of Catalonia (NE Spain) to test well stablished agronomic practices to increase the adaptation of Mediterranean mid mountain to climate change. Soil water content (SWC) at three different depths (15, 30 and 45cm) was measured in continuum from August 2020. One pilot (WC) included a well-established green cover (GC), a new GC (NC) and a conventional soil management (CM, tilling+herbicides). NC presented an intermediate state between WC and CM, responding similarly to CM in autumn but quickly reaching similar SWC to WC, then following the same evolution till next spring, with CM presenting lower values along autumn and winter. Then vegetation activation decreased SWC in all plots, (much slower in CM, lacking GC). Sensibility to spring rains is again intermediate for NC, which joins SWC evolution of CM by the end of spring till next autumn. It is expected that NC will resemble WC more and more as its GC develops. In the pilot combining vine training (VSP vs Gobelet) and hillside management (slope vs terrace), no clear pattern could be related with these conditions. However, both terraces seem to be more sensitive to spring rains. A third pilot included new vineyards (7 and 1 year old). In the new vineyard (N), higher canopy development, a spontaneous green cover and row straw resulted in a slower SWC dynamic, not so sensitive to rains but conserving more soil water in spring and most of summer, even with presumably a higher water extraction by vines. In the newest vineyard (VN) the deepest sensor is still sensitive to rain events all over the year and SWC is always highest at this depth, revealing small water capture by vines.

Current climate change in the Oplenac wine-growing district (Serbia)

Serbian autochthonous vine varieties Smederevka (for white wines) and Prokupac (for rosé and red wines) are the primary representatives of typical characteristics of wines and terroir of numerous wine-growing areas in Serbia. In the past, these varieties were the leading vine varieties, however, as the result of globalization of winemaking and the trend of consumption of wines from widely prevalent vine varieties, they were replaced by introduced international varieties. Smederevka and Prokupac vine varieties are characterized by later time of grape ripening, and relative sensitivity to low temperatures. Climate conditions can be a restrictive factor for production of high-quality grapes and wine and for the spatial spreading of these varieties in hilly continental wine-growing areas.
This paper focuses on the spatial analysis of changes of main climate parameters, in particular, analysis of viticultural bioclimatic indices that were determined for the purposes of viticulture zoning of wine-growing areas in the period 1961-2010, and those same parameters determined for the current, that is, referential climate period (1988-2017). Results of the research, that is, analysis of climate changes indicate that the majority of examined climate parameters in the Oplenac wine-growing district improved from the perspective of Smederevka and Prokupac vine varieties. These studies of climate conditions indicate that changes of analyzed climate parameters, that is, bioclimatic indices will be favorable for cultivation of varieties with later grape ripening times and those more sensitive to low temperatures, such as the autochthonous vine varieties Smederevka and Prokupac, therefore, it is recommended to producers to more actively plant vineyards with these varieties in the territory of the Oplenac wine-growing district.

Upscaling the integrated terroir zoning through digital soil mapping: a case study in the Designation of Origin Campo de Borja

homogeneous zones by intersecting several partial zonings of major factors that influence vineyard growth. Each of them follows specific process from their corresponding disciplines. Soil zoning specifically refers to a Soil Resource Inventory map that has traditionally been generated by conventional soil mapping methods. These methods have shortcomings in reaching fine cartographic and categorical details and involve significant expenses, which undermines their applicability. A new framework named Digital Soil Mapping has introduced quantitative models by statistical techniques to establish soil-landscape relationships and is able to provide intensive scale cartography.

In the present study, a microzoning at 1:10.000 scale is generated from an initial zoning, where the conventional soil map with polytaxic map units is replaced by a new one from digital techniques that disaggregates them. The comparison between the zonings considers a quantitative evaluation of capability for each Homogeneous Terroir Unit by means of the Viticultural Quality Index and its categorization based on its distribution by map. The spatial intersection of both maps gives rise to a confusion matrix in which the flows of class variations after the substitution are assessed.

The results show a five-fold increase in the number of Homogeneous Terroir Units identified and a larger differentiation among them, evidenced by a wider range in the capability index distribution. Both elements are accompanied by an increase in the detection of areas of higher potential within previously undervalued uniform zones.These features are a direct effect of the improvements brought by Digital Soil Mapping techniques and would verify the advantages of their implementation in the Integrated Terroir zoning. Eventually, such new highly detailed terroir units would benefit precision viticulture and sustainable management practices.