IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Early fermentation aroma profiles of grape must produced by various non-Saccharomyces starters

Early fermentation aroma profiles of grape must produced by various non-Saccharomyces starters

Abstract

Saccharomyces cerevisiae is the most commonly used yeast species in winemaking. The recent research showed that non-Saccharomyces yeasts as fermentation starters show numerous beneficial features and can be utilized to reduce wine alcoholic strength, regulate acidity, serve as bioprotectants, and finally improve wine aromatic complexity. The majority of published studies on this topic investigated the influence of sequential or co-inoculations of non-Saccharomyces and S. cerevisiae yeasts on the aroma of final wine. Although some results are consistent with each other, there are many contrasting and contradicting outcomes, which most likely derived from the differences in grape juice composition, as well as due to various combinations and interactions of non-Saccharomyces and S. cerevisiae strains used in different studies. For these reasons, the actual contribution of non-Saccharomyces yeasts was often not completely distinguishable. The main premise of this study was that by investigating the production of volatile aroma compounds produced by non-Saccharomyces yeasts in the early phase of fermentation, prior to interaction with S. cerevisiae, a valuable insight from another perspective can be achieved about the particular effects they induce. Malvazija istarska (Vitis vinifera L.) white grape must was inoculated with the following non-Saccharomyces yeasts: Torulaspora delbrueckii, Metschnikowia
pulcherrima, Pichia kluyveri, Lachancea thermotolerans and Schizosaccharomyces pombe, while Saccharomyces cerevisiae was used as a control. The fermenting grape musts were subjected to headspace solid-phase microextraction and gas-chromatography-mass spectrometric analysis at the point just before S. cerevisiae inoculation, when alcohol level reached 1.5 – 2.5 vol. %. Each of the investigated non-Saccharomyces yeasts produced a
unique and distinctive aroma profile. The highest concentrations of linalool and β-damascenone were found in the must fermented by Pichia kluyveri and the lowest in the control S. cerevisiae must. The concentration of 2-phenylethanol produced by S. cerevisiae almost doubled those found in the musts of non-Saccharomyces starters. Ethyl propanoate differentiated well the investigated yeasts, with the highest concentration found in T.
delbrueckii must. This must also contained the highest concentrations of some other propanoates, including 2-phenethyl propanoate which turned out to be specific for this species. Particular non-Saccharomyces yeasts boosted the early synthesis of many important esters, such as ethyl hexanoate, ethyl octanoate and 2-phenethyl acetate, the main contributors to fruity and flowery notes of wine aroma. The obtained results showed that the potential of the investigated non-Saccharomyces yeasts to produce diverse wines is rather high. This study was funded by Croatian Science Foundation under the projects IP-2020-02-4551 and DOK-2021-02-5500.

DOI:

Publication date: June 24, 2022

Issue: IVAS 2022

Type: Poster

Authors

Delač Salopek Doris1, Horvat Ivana1, Hranilovic Ana2, Plavsa Tomislav1, Radeka Sanja1, Paskovic Igor1 and Lukic Igor1 

1Institute for Agriculture and Tourism
2Department of Wine Science, The University of Adelaide 

Contact the author

Keywords

non-Saccharomyces yeasts, sequential inoculation, SPME-GC-MS, volatile aroma compounds, esters

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

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.

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.

A spatial explicit inventory of EU wine protected designation of origin to support decision making in a changing climate

Winemaking areas recognized as protected designations of origin (PDOs) shape important economic, environmental and cultural values that are tied to closely defined geographic locations. To preserve wine products and wine-growing practices adopted in different PDOs these areas are strictly regulated by legal specifications. However, quality viticulture is increasingly under pressure from climate change, which is altering the local conditions of many winegrowing areas. Therefore, maintaining traditional wine products will require the adoption of tailored adaptation strategies, including possible changes in the legal regulation of protected wines. To this end, it is necessary to have a comprehensive knowledge on PDOs including their extension, products and allowed practices. While there have been efforts to build databases that summarize the characteristics for individual wine PDO areas and to quantify the related effects of climate change, much information is still included only in the official documentation of the EU geographical indication register and has never been collected in a comprehensive manner. With this study we aim at filling this gap by building a spatial inventory of European wine PDOs that supports decision making in viticulture in the context of climate change. To map and characterize European wine PDOs, we analysed their legal documents and extracted relevant information useful for climate change adaptation. The output consists of a comprehensive geographical dataset that identifies the boundaries of all 1200 European wine PDOs at unprecedented spatial resolution and includes a set of legally binding regulations, such as authorized vine varieties, maximum yields and planting density. The inventory will allow researchers to analyse the impacts of climate change on European wine PDOs and support decision makers in developing tailored adaptation strategies. This includes, among others, the evaluation of new vineyard site selection, the expansion of cultivated varieties or the authorization of irrigation in vineyards.

Climate, Viticulture, and Wine … my how things have changed!

The planet is warmer than at any time in our recorded past and increasing greenhouse emissions and persistence in the climate system means that continued warming is highly likely. Climate change has already altered the basic framework of growing grapes for wine production worldwide and will likely continue to do so for years to come. The wine sector can continue to play an important role in leading the agricultural sector in addressing climate change. From developing on…

Evaluation of climate change impacts at the Portuguese Dão terroir over the last decades: observed effects on bioclimatic indices and grapevine phenology

In the last decades the growers of the Portuguese Dão winegrowing region (center of Portugal) are experiencing changes in climate that are influencing either grape phenology berry health and ripening. Aiming to study the relationships between climate indices (CI), seasonal weather and grapevine phenology, in this work long-term climate and phenological data collected at the experimental vineyard of the Portuguese Dão research centre between 1958 and 2019 (61 years) for the red variety Touriga Nacional, was analyzed. The trends over time for the classical temperature-based indices (Growing Season Temperature – GST -, Growing Degree Days – GDD, Huglin Index – HI and Cool Night Index – CI) presented a significantly positive slope while the Dryness Index (DI) showed a negative trend over the last 61 years. Regarding grapevine phenology, an average advance of 4.5 days per decade in the harvest day was observed throughout the last 61 years. Consequently, the weather conditions during the ripening period have changed, showing an increasing trend over time in the average temperature (higher magnitude in the maximum than in the minimum temperature) and a decrease in the accumulated rainfall. A regression analysis showed that ~50% of harvest date variability over years was explained by the temperature-based indices variability. These observed effects of climate change on bioclimatic indices and corresponding anticipation of harvest date can still be considered advantageous for the Dão terroir as it allows to achieve an optimal berry ripening before the common equinox rains and, therefore, avoid the potential negative impacts of the rainfall on berry health and composition.