IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Assyrtiko wines of Santorini produced by different autochthonous yeasts: Differences in aromatic and organoleptic profiles

Assyrtiko wines of Santorini produced by different autochthonous yeasts: Differences in aromatic and organoleptic profiles

Abstract

Different yeasts were isolated from spontaneous fermentation of Assyrtiko grape must in Santorini Island, Greece. Molecular typing revealed the presence of three Saccharomyces cerevisiae strains (S9, S13, S24) and one strain of the yeast species Nakazawaea ishiwadae (N.i). The four isolated strains were further tested in laboratory scale fermentations of Assyrtiko must in pure inoculation cultures and in sequential inoculation (72 hours) of each S. cerevisiae strain with the strain of N. ishiwadae. All fermentation trials were realised in duplicate.

 Fermentation kinetics were followed by HPLC, while the volatile composition of the final products was determined by GC-MS (qualitative analysis) and GC-FID (quantitative analysis). Sensory evaluation of the samples took place by a panel of 10 trained panellists. In general, the fermentation rate in trials with S.13 and N.i. was lower than the rest, while trials with S9 and S24 resulted in higher ethanol contents in the final product but without statistically important differences. The wines fermented with the S24 and N.i. strains were characterised by the highest concentrations of acetic acid (0.9 and 0.7 g/L respectively) and with S13 by the highest concentration of glycerol (15g/L). In terms of aromatic profile, the trials contacted with S9 were up to 3.5-folds richer in volatile compounds responsible for the fruity character in wines. In addition, the fermentations with S13 and N.i. were about 3-folds richer in compounds characterized by floral character (e.g. phenethyl alcohol, tyrosol etc.), while the most abundant group of compounds in fermentations contacted with S24 strain were the oxidation esters (e.g. ethyl hydrogen succinate). In the sequential inoculations apart from a delay in the completion of alcoholic fermentations, a comparable with single strains fermentations trend in ethanol production and reducing sugar consumption was observed. Intensification of the production of acetic acid, oxidation esters, several ethyl esters and higher alcohols (C5, C6) was also observed. Significantly lower (5-fold) contents of higher alcohols and their corresponding esters, responsible for floral aromas for ferments with N13 compared to ferments with S13 was also noted. Regarding the production of esters responsible for tropical and citrus aromas (e.g. isoamyl acetate, ethyl hexanoate), the highest content was observed in ferments with N13 (1.32 ppm) and N24 (1.97 ppm) while the lowest in ferments with N9 (0.99 ppm). The concentration of most esters was increased for all trials after sequential inoculation compared to the corresponding trials contacted with pure cultures.  The results from the organoleptic analysis are in line with the chemical analysis. Even though, all four newly isolated strains have the ability to ferment and produce dry wines, the most preferred wines by the panel were those produced by S9 and S13 strains.

DOI:

Publication date: June 27, 2022

Issue: IVAS 2022

Type: Poster

Authors

Kallithraka Stamatina1, Christofi Stefania1, Dimopoulou Maria1, Tsapou Evangelia Anastasia1 and Papanikolaou Seraphim1

1Department of Food Science and Human Nutrition, Laboratory of enology and alcoholic drinks, Agricultural University of Athens 

Contact the author

Keywords

Saccharomyces cerevisiae, Nakazawaea ishiwadae, wine volatile content, sensory analysis, fermentation kinetics

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

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.

Permanent cover cropping with reduced tillage increased resiliency of wine grape vineyards to climate change

Majority of California’s vineyards rely on supplemental irrigation to overcome abiotic stressors. In the context of climate change, increases in growing season temperatures and crop evapotranspiration pose a risk to adaptation of viticulture to climate change. Vineyard cover crops may mitigate soil erosion and preserve water resources; but there is a lack of information on how they contribute to vineyard resiliency under tillage systems. The aim of this study was to identify the optimum combination of cover crop sand tillage without adversely affecting productivity while preserving plant water status. Two experiments in two contrasting climatic regions were conducted with two cover crops, including a permanent short stature grass (P. bulbosa hybrid), barley (Hordeum spp), and resident vegetation under till vs. no-till systems in a Ruby Cabernet (V. vinifera spp.) (Fresno) and a Cabernet Sauvingon (Napa) vineyard. Results indicated that permanent grass under no-till preserved plant available water until E-L stage 17. Consequently, net carbon assimilation of the permanent grass under no-till system was enhanced compared to those with barley and resident vegetation. On the other hand, the barley under no-till system reduced grapevine net carbon assimilation during berry ripening that led to lower content of nonstructural carbohydrates in shoots at dormancy. Components of yield and berry composition including flavonoid profile at either site were not adversely affected by factors studied. Switching to a permanent cover crop under a no-till system also provided a 9% and 3% benefit in cultural practices costs in Fresno and Napa, respectively. The results of this work provides fundamental information to growers in preserving resiliency of vineyard systems in hot and warm climate regions under context of climate change.

The concept of terroir: what place for microbiota?

Microbes play key roles on crop nutrient availability via biogeochemical cycles, rhizosphere interactions with roots as well as on plant growth and health. Recent advances in technologies, such as High Throughput Sequencing Techniques, allowed to gain deeper insight on the structure of bacterial and fungal communities associated with soil, rhizosphere and plant phyllosphere. Over the past 10 years, numerous scientific studies have been carried out on the microbial component of the vineyard. Whether the soil or grape compartments have been taken into account, many studies agree on the evidence of regional delineations of microbial communities, that may contribute to regional wine characteristics and typicity. Some authors proposed the term “microbial terroir” including “yeast terroir” for grapes to describe the connection between microbial biogeography and regional wine characteristics. Many factors are involved in terroir including climate, soil, cultivar and human practices as well as their interactions. Studies considering “microbial terroir” greatly contributed to improve our knowledge on factors that shape the vineyard microbial structure and diversity. However, the potential impact of “microbial terroir” on wine composition has yet not received strong scientific evidence and many questions remain to be addressed, related to the functional characterization of the microbial community and its impact on plant physiology and grape composition, the origins and interannual stability of vineyard microbiota, as well as their impact on wine sensorial attributes. The presentation will give an overview on the role of microbiota as a terroir component and will highlight future perspectives and challenges on this key subject for the wine industry.

Copper contamination in vineyard soils of Bordeaux: spatial risk assessment for the replanting of vines and crops

Copper (Cu) is widely and historically used in viticulture as a fungicide against mildew. Cu has a strong affinity for soil organic matter and accumulates in topsoil horizons. Thus, Cu may negatively affect soil organisms and plants, consequently reducing soil fertility and productivity. The Bordeaux vineyards have the largest vineyard surfaces (26%) within French controlled appellation and a great proportion of French wine production (around 5 million hl per year). Considering the local context of vineyard surfaces decreasing (vine uprooting) and possible new crop plantation, the issue of Cu potential toxicity rises. Therefore, the aims of this work are firstly to evaluate the Cu contamination in vineyard soils of Bordeaux, secondly to produce a risk assessment map for new vine or crop plantation. We used soil analyses from several local studies to build a database with 4496 soil horizon samples. The database was enhanced by means of pedotransfer functions in order to estimate the bioaccessible (EDTA-extractable) Cu in soils of samples without measurements. From this database, 1797 georeferenced samples with CuEDTA concentrations in the topsoil (0-50 cm depth) were used for kriging interpolation in order to produce the spatial distribution map of CuEDTA in vineyard soils. Then, the spatial distribution of Cu was crossed with vine uprooting surfaces and municipality boundaries. CuEDTAconcentrations ranged from 0.52 to 459 mg/kg and showed clear anomalies. Our results from spatial analysis showed that almost 50% of vineyard soil surfaces have CuEDTA concentrations higher than 30 mg/kg (moderate risk for new plantation) and 20% with concentrations higher than 50 mg/kg (high risk for new plantation). A decision-support map based on municipalities was realised to provide a simple tool to stakeholders concerned by land use management.

How can historical cultivars mitigate the effects of climate change?

IFV, INRAe and the national network “Partenaires de la Sélection Vigne” representing 37 organizations from the different wine regions, have been working increasingly closely over the last 2 decades towards the preservation of the French varietal patrimony. There are approximately 600 patrimonial varieties according to INRAe and SupAgro Montpellier experts, including ancient cultivars (400) and intravarietal crossbreeds obtained since the 19th century. In the context of a drastic reduction in such varieties from the mid 1980’s in favor of mainstream varieties, it was essential to carry out an inventory of old vines and vineyards. INRAe Vassal collection plays a key role here as it holds the largest diversity available, along with a rich bibliography and herbariums, offering us the opportunity to document and double check the identity of a cultivar, consolidating the expertise of ampelographers. The work is carried out in several stages, from verifying the existence of a variety in a small region, through to rehabilitation. During this session, the authors present the process that leads to the official registration of a variety. After this, IFV selection center takes over to initiate the process of selection and propagation. A specific focus within regions such as the Alps, Champagne and the South-West will provide details of the full procedure. Bia, Bouysselet, Chardonnay rose, Mecle and the aptly named Tardif, are some of the cultivars that have followed this procedure. Furthermore, a recent regulation established by INAO on “varieties of interest for adaptation purposes” might boost uptake by growers. Since 2006, 36 historical cultivars have been registered. Most of these have been neglected in the past due to late maturity, lack of sugar and high titratable acidity at harvest time. Such characteristics are today considered as positive qualities, not only in mitigation of the effects of climate change, but also as an opportunity for restoring diversity…