Macrowine 2021
IVES 9 IVES Conference Series 9 Response of different nitrogen supplementation on Saccharomyces cerevisiae metabolic response and wine aromatic profile

Response of different nitrogen supplementation on Saccharomyces cerevisiae metabolic response and wine aromatic profile

Abstract

The wine yeast Saccharomyces cerevisiae can highly affect wine aromatic profile by producing and/or mediating the release of a whole range of metabolites (such as thiols, esters, and terpenes), which in turn contribute to enhanced aroma and flavor. These metabolites depend on yeast metabolism activated during fermentation which can constitute the ‘’metabolic footprint’’ of the yeast strain that carried out the process. The aim of the present research was to study the metabolism of S. cerevisiae under two different nitrogen supplementation status and to investigate the relative expression of specific genes, that are directly related to the biosynthesis of specific potent odornats such as, terpenes and esters. 

The commercial yeast strains 1X (S.cerevisiae) and 2X (S.cerevisiae x S.bayanus) were inoculated in Moschofilero (Vitis Vinifera L. cv) grape must under two different concentrations of yeast assimilable nitrogen (YAN), a  low at 150 mg/L and a high at 300 mg/L. The produced wines were analyzed for their standard enological parameters, their volatile composition by SPE/GC–MS analysis as well as for their sensory profile. Totally 8 fermentations trials, were realised in triplicate. The fermentation was monitored by measuring the optical density and sugar consumption. Metabolic response was tested through real-time RT-PCR of genes implicated in aroma production of esters and terpenes such as ATF1, ATF2, EEB1, EHT1, IAH1, BGL2, EXG1. Sampling for metabolites and gene expression analysis were taken at the time of inoculation, after 48 hours, when two thirds of the sugars were depleted and at the end of the alcoholic fermentation (< 2g/L rs).

In terms of the volatile characterization of the wines, esters, linalool and nerol appeared to be clearly distinct between the different levels of YAN, which confirms the specialization in volatile compounds production among different nitrogen concentration levels. For instance, linalool was found to be at 0.05 mg/L for low nitrogen concentration, while high nitrogen levels resulted to a concentration of 0.12 mg/L. Real-time-PCR results revealed that, in both cases of nitrogen implementation, the analyzed genes were found to be expressed mainly before the fermentation of the 70% of the sugars. In addition, an overexpression of the BGL2 gene, corresponded well to the linalool concentration found, was observed in case of high nitrogen condition. Also, the EHT1 was expressed five times higher in case of high nitrogen concentration. Finally, correlations between ethyl esters and EEB1, acetate esters and ATF2 (p<0.05) were also found in both cases. 

Our study revealed the impact of different nitrogen implementations on the volatile compounds and the relative expression of specific genes. Metabolic analysis of selected volatile components of the wine aroma in conjunction with transcriptional analyses provide a great approach to orient the fermentation process towards a desirable wine aromatic profile.

DOI:

Publication date: September 3, 2021

Issue: Macrowine 2021

Type: Article

Authors

Despina Lola, Chrysanthi KALLONIATI, Maria DIMOPOULOU, Maria Ioanna XENIA, Emmanouil FLEMETAKIS, Yorgos KOTSERIDIS

Laboratory of Oenology and Alcoholic Drinks (LEAD), Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece, Laboratory of Molecular Biology, Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece, Department of Wine, Vine and Beverage Sciences, School of Food Science, University of West Attica, Greece, Laboratory of Oenology and Alcoholic Drinks  (LEAD), Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece Laboratory of Molecular Biology, Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece, Laboratory of Enology and Alcoholic Drinks (LEAD), Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece

Contact the author

Keywords

yeast metabolism, yan, nitrogen supplementation, volatile profile, gene expression

Citation

Related articles…

Differential responses of red and white grape cultivars trained to a single trellis system – the VSP

Commercial grape production relies on training grapevine cultivars onto a variety of trellis systems. Training allows for well-lit leaves and clusters, maximizing fruit quality in addition to facilitating cultivation, harvesting, and diseases control. Although grapevines can be trained onto an infinite variety of trellis systems, most red and white cultivars are trained to the standard VSP (Vertical Shoot Positioning) system. However, red and white cultivars respond differently to VSP in fruit composition and growth characteristics, which are yet to be fully understood. Therefore, the objective of this study was to examine the influence of the VSP trellis system on fruit composition of three red, Cabernet Sauvignon, Merlot and Syrah, and three white, Chardonnay, Riesling, and Gewurztraminer cultivars grown under uniform growing conditions in the same vineyard. All cultivars were monitored for maturity and harvested at their physiologically maximum possible sugar concentration to compare various fruit quality attributes such as Brix, pH, TA, malic and tartaric acids, glucose and fructose, potassium, YAN, and phenolic compounds including total anthocyanins, anthocyanin profile, and tannins. A distinct pattern in fruit composition was observed in each cultivar. In regards to growth characteristics, Syrah grew vigorously with the highest cluster weight. Although all cultivars developed pyriform seeds, the seed size and weight varied among all cultivars. Also varied were mesocarp cell viability, brush morphology, and cane structure. This knowledge of the canopy architectural characteristics assessed by the widely employed fruit compositional attributes and growth characteristics will aid the growers in better management of the vines in varied situations.

Exploring resilience and competitiveness of wine estates in Languedoc-Roussillon in the recent past: a multi-level perspective

The Languedoc-Roussillon wineries are facing a decline in wine yields particularly PGI yields due to many factors. Climate change is just ones, but is expected to increase in the future. There is also structurally a large heterogeneity of yield profiles among terroirs, varieties and strategies. This work investigates the link between yield, competitiveness and resilience to explore how resilient winegrowers have been in the recent past. To this end two approaches have been combined; (i) an accountancy database analysis at estate scale and (ii) municipality level competitiveness analysis. A new resilience indicator that characterizes the capacity of an estate to absorb yield variation is also defined. The FADN database between 2000 and 2018 of ex-Languedoc-Roussillon (France) and other data are used to analyse the current situation and the past evolution of competitiveness and resilience by type of estate (type of farm: PGI and/or PDO & type of commercialization: bulk and/or bottles). The net margin, which defines competitiveness, is not correlated to yield for all types but depends on the type of commercialization and the level of specialisation. The resilience indicator shows that the net margin of estates specialized in PGI is particularly sensitive to yield declines. We also show that price evolutions seem to compensate the effect of yield losses for the majority of types. Municipality scale analysis shows the links between local pedoclimate, yield, commercialization strategies and price. Overlapping a PDO with a PGI does not always increase a municipality’s PGI competitiveness. It is difficult to make links between causes and effects due to the complexity of the wine production system. Production diversification may be a solution. Resorting to the two level of analysis helps resolving the data gap that is necessary to explore the links between yield and economic performance of the wine estates in the long term.

austrianvineyards.com: online viewer of all designations of Austrian wine

To digitally record and present all the origins of Austrian wines in the same perfect and clear way was the motivation for the Austrian Wine Marketing Board (Austrian Wine) to start with the project in 2018. In June 2021 the results were presented to the public in an online viewer showing all the designations of Austrian wine, available at https://austrianvineyards.com in a largely barrier-free manner. The online viewer provides tailored individual maps fitted to the respective zoom level. The smallest unit of wine-origins in Austria is called Ried and is displayed in a plot-specific manner highlighting areas under vine. Information on the Ried include administrative district, winegrowing municipality, cadastral municipality, large collective vineyard site, specific winegrowing region, generic winegrowing region, winegrowing area and, in many cases, an illustrative picture. Complementary data on the size, elevation (minimum-maximum), orientation (in 8 sectors plus flat) and gradient (minimum, maximum, average) are based on the area under vine according to the EU’s Integrated Administration and Control System. Additional information covers climate data. The diagrams are taken from the monthly breakdown of data in the annals of the Central Institute for Meteorology and Geodynamics, Austria provide a display of values for air temperature, precipitation, and sunshine hours for the reference year and the long-term average. Seasonal aggregated data on temperature, precipitation, and sunshine hours complete the display. Short descriptions with emphasis on geology and soil, field name in historical maps, etymology of the denomination, and main planted variety complements the available information for the main designations in the online viewer. These descriptions are compiled by winegrowers, geologists, historians, and journalists. All the information and data can be extracted to a pdf-file. Printed vineyard maps are also available. Missing content regarding wine origins in Styria will be completed in winter 2021/22.

Impact of changes in pruning practices on vine growth and yield

A gradual decline in vineyards has been observed over the past twenty years worldwide. This might be explained by the climate change, practices change or the increase of dieback diseases. To increase the longevity of vines, we studied the impact of different pruning strategies in four adult and four young vineyards located in France and Spain. In France, vineyards were planted with Cabernet franc on 3309C while Spanish trials were planted with Tempranillo grafted on 110R. Vegetative expression, yield, quality of berries and wood vessels conductivity were measured. The distribution of vegetative expression, yield and berry composition between primary and secondary vegetation were quantified. Finally, tomography was used to evaluate the implication of the treatments on sap flows.
First results show that i) the respectful pruning leads to an increase of 30 to 50% more secondary shoots than the aggressive pruning in France and between 15 and 20% in Spain, ii) there is no major effect on the yield over the first two years following the implementation of the new pruning practices, although the proportion of clusters from suckers is higher on the respectful pruning method. On young vines, the development of the trunk according to a respectful pruning leads to a loss of harvest 2 years after planting. This is due to the removal, on the future trunk, of the green suckers which carrying bunches. This operation carried out in spring rather than during winter pruning, would promote a better leaf / fruit balance when the plant comes into production, and could lead to better hydraulic conduction in the vessels of the trunk. Maintaining these trials for several years will provide more robust data to assess the impact of these practices on the vines over the long term.

Underpinning terroir with data: rethinking the zoning paradigm

Agriculture, natural resource management and the production and sale of products such as wine are increasingly data-driven activities. Thus, the use of remote and proximal crop and soil sensors to aid management decisions is becoming commonplace and ‘Agtech’ is proliferating commercially; mapping, underpinned by geographical information systems and complex methods of spatial analysis, is widely used. Likewise, the chemical and sensory analysis of wines draws on multivariate statistics; the efficient winery intake of grapes, subsequent production of wines and their delivery to markets relies on logistics; whilst the sales and marketing of wines is increasingly driven by artificial intelligence linked to the recorded purchasing behaviour of consumers. In brief, there is data everywhere!

Opinions will vary on whether these developments are a good thing. Those concerned with the ‘mystique’ of wine, or the historical aspects of terroir and its preservation, may find them confronting. In contrast, they offer an opportunity to those interested in the biophysical elements of terroir, and efforts aimed at better understanding how these impact on vineyard performance and the sensory attributes of resultant wines. At the previous Terroir Congress, we demonstrated the potential of analytical methods used at the within-vineyard scale in the development of Precision Viticulture, in contributing to a quantitative understanding of regional terroir. For this conference, we take this approach forward with examples from contrasting locations in both the northern and southern hemispheres. We show how, by focussing on the vineyards within winegrowing regions, as opposed to all of the land within those regions, we might move towards a more robust terroir zoning than one derived from a mixture of history, thematic mapping, heuristics and the whims of marketers. Aside from providing improved understanding by underpinning terroir with data, such methods should also promote improved management of the entire wine value chain.