IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Applications of FTIR microspectroscopy in oenology: shedding light on Saccharomyces cerevisiae cell wall composition and autolytic capacity

Applications of FTIR microspectroscopy in oenology: shedding light on Saccharomyces cerevisiae cell wall composition and autolytic capacity

Abstract

Many microbial starters for the alcoholic and malolactic fermentation processes are commercially available, indicated for diverse wine styles and quality goals. The screening protocols cover a wide range of oenologically relevant features, although some characteristics could also be studied using underexplored powerful techniques. In this study, we applied Fourier Transform Infrared (FTIR) microspectroscopy [1,2] to compare the cell wall biochemical composition and monitor the autolytic process in several wine strains of Saccharomyces cerevisiae. After cell death, autolysis trigger the release of mannoproteins and β-glucans, major components of yeast cell walls, influencing color, aroma, body, foaming properties, and stability of wine. Moreover, they can stimulate the metabolism of malolactic bacteria, while some fatty acids, also released during autolysis, act as inhibitors. Analysis of the cell wall structure was carried out both on cells grown in liquid medium and on cell walls previously separated from the other components. The autolytic capacity was assayed by sampling the cells at different times during induced autolysis in clarified and pasteurized must. From five to ten infrared spectra were acquired on each sample in the 4,000-700 cm-1 range in Attenuated Total Reflection on a 50×50 μm2 area. Spectra were analyzed after pretreatment through Hierarchical Cluster Analysis and Principal Component Analysis. Preliminary results were evaluated in relation to conventional spectrophotometric methods to quantify mannoproteins and β-glucans. The thickness of the cell walls was determined by means of scanning (SEM) and transmission electron microscopy (TEM). From the point of view of cell wall composition two groups of yeasts were distinguished by multivariate statistical analysis on the FTIR spectra since the strains EC1118, MY11 and PEDRO2000E showed higher absorption bands of mannoproteins and β-glucans. With conventional methods, the cell walls of the first two strains, alongside K1 and MY8, displayed a higher content of parietal polysaccharides, while the latter had the thickest wall among all the tested yeasts. The strains BM45 and D47 have a thinner surface structure. Regarding the autolytic process, again two different clusters were found distinguishing the behavior of the strains EC1118 and FRB with a similar timing of autolysis on one side from CH and Q20 on the other side. Furthermore, the latter strain presented a higher absorption in the spectral zone related to lipids, which can be correlated with a greater release of fatty acids in the medium. In conclusion, FTIR microspectroscopy proved to be an accurate and informative technique, suitable to highlight profound differences among S. cerevisiae strains as concerns both the content of parietal polysaccharides and the evolution of autolysis. Thus, this technique may become an option for the selection of starter cultures with properties fo great interest for the wine sector.

References

[1] Burattini, E., Cavagna, M., Dell’Anna, R., Malvezzi Campeggi, F., Monti, F., Rossi, F., & Torriani, S. (2008). A FTIR microspectroscopy study of autolysis in cells of the wine yeast Saccharomyces cerevisiae. Vibrational Spectroscopy, 47(2), 139-147. https://doi.org/10.1016/j.vibspec.2008.04.007.
[2] Cavagna, M., Dell’Anna, R., Monti, F., Rossi, F., & Torriani, S. (2010). Use of ATR-FTIR microspectroscopy to monitor autolysis of Saccharomyces cerevisiae cells in a base wine. Journal of Agricultural and Food Chemistry, 58(1), 39–45. https://doi.org/10.1021/jf902369s.

DOI:

Publication date: June 27, 2022

Issue: IVAS 2022

Type: Poster

Authors

Martelli Francesco1, Binati Renato Leal1, Monti Francesca2, Felis Giovanna1 and Torriani Sandra1

1Department of Biotechnology, University of Verona 
2Department of Computer Science, University of Verona

Contact the author

Keywords

FTIR microspectroscopy; starter cultures; Saccharomyces cerevisiae; autolysis; wine quality

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

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.

Effects of graft quality on growth and grapevine-water relations

Climate change is challenging viticulture worldwide compromising its sustainability due to warmer temperatures and the increased frequency of extreme events. Grafting Vitis vinifera L.

Grape must quality and mesoclimatic variability in Fruška Gora wine-growing region, Serbia

The Fruška Gora mountain is a traditional wine-growing region in Serbia situated in the Pannonian Basin. Due to such a position, the vicinity of the Danube River and the presence of concave configuration, it is suitable for grape production. This paper provides analyses of spatial variations in meteorological parameters and grape juice quality within Fruška Gora wine region over three consecutive vintages (2018-2020). The examined period can be defined as warm with cool nights during September (AVG 18,9°C; GDD 1918°C; CI 12°CF) and with the presence of mesoclimatic variability. The East part of the study area was somewhat drier and hotter compared to other parts of the region. The analyses of grape must samples (190 in total) of five cultivars (Cabernet-Sauvignon, Merlot, Chardonnay, Sauvignon blanc and Grašac (Welschriesling)) commonly grown across the region (19 sites), were performed using Fourier Transform Infrared Technology (FTIR). Among all cultivars, Sauvignon blanc was harvested first in the East area (DOY=246±5, GDD at harvest=1552±74, 22.2±0.7 °Brix), while the latest harvest was recorded for Cabernet-Sauvignon in the West (DOY=283±5, GDD at harvest=1936±187, 23.4±1.0 °Brix ). Both the red and white cultivars had higher acidity and YAN in the grape must if the vines were grown in the North and East compared to South and West areas. According to PCA analysis, Grašac showed the lowest variation in grape must chemical composition. Thus, the results confirm that Grašac is the most stable cultivar in Fruška Gora. All monitored cultivars reached technological fruit ripeness by the end of the growing season. However, it was difficult to reach full ripeness of red cultivars, mostly beacuse of uncoupling of technolocical and phenolic ripeness. Thus, Cabernet-Sauvignon had higher variations in GDD sums at harvest compared to other cultivars, which probably increased variations in grape must quality.

Simulating climate change impact on viticultural systems in historical and emergent vineyards

Global climate change affects regional climates and hold implications for wine growing regions worldwide. Although winegrowers are constantly adapting to internal and external factors, it seems relevant to develop tools, which will allow them to better define actual and future agro-climatic potentials. Within this context, we develop a modelling approach, able to simulate the impact of environmental conditions and constraints on vine behaviour and to highlight potential adaptation strategies according to different climate change scenarios. Our modeling approach, named SEVE (Simulating Environmental impacts on Viticultural Ecosystems), provides a generic modeling framework for simulating grapevine growth and berry ripening under different conditions and constraints (slope, aspect, soil type, climate variability…) as well as production strategies and adaptation rules according to climate change scenarios. Each activity is represented by an autonomous agent able to react and adapt its reaction to the variability of environmental constraints. Using this model, we have recently analyzed the evolution of vineyards’ exposure to climatic risks (frost, pathogen risk, heat wave) and the adaptation strategies potentially implemented by the winegrowers. This approach, implemented for two climate change scenarios, has been initiated in France on traditional (Loire Valley) and emerging (Brittany) vineyards. The objective is to identify the time horizons of adaptations and new opportunities in these two regions. Carried out in collaboration with wine growers, this approach aims to better understand the variability of climate change impacts at local scale in the medium and long term.

First step in the preparation of a soil map of the Protected Designation of Origin Valdepeñas (Central, Spain)

This work is a first step to make a map of vineyard soils. The characterization of the soils of the Protected Designation of Origin (D.P.O.) Valdepeñas will allow to group the studied profiles according to their physico-chemical characteristics and the concentrations of most relevant chemical elements. 90 soil profiles were analysed throughout the territory and the soils were sampled and described according to FAO (2006) and classified according to and Soil Taxonomy (2014). All samples were air dried, sieved and some physico-chemical parameters were determined following standard protocols. Also, major and trace elements were analysed by X-ray fluorescence. The statistically study was made using the SPSS program. Trend maps were made using the ArcGIS program. The studied soils have the following average properties: pH, 8.3; electrical conductivity, 0,20 dS/m (low); clay, 18.8% (medium) and CaCO3, 17.1% (high). In the study for the major elements. The major elements of these soils are Si, followed by Ca and Al, with an average content of 203.7 g/kg, 105.5 g/kg and 74.0 g/kg respectively. On the other hand, 27 trace elements have been studied. Of all of them, it can be highlighted the average values of Ba (361.8 mg/kg), Sr (129.3 mg/kg), Rb (83.4 mg/kg), V (74.2 mg/kg) and Ce (70.6 mg/kg). Ba, V and Ce values are higher and the values of Sr and Rb are lower to those found in the literature. The discriminant analysis shows a percentage of grouping of 91%. The content of chemical elements together with the physico-chemical characteristics allows grouping the soils in 4 group according to their order in the classification to Soil Taxonomy; due to the importance of the Calcisols in Castilla-La Mancha, it has been decided to establish them as their own group even if they do not appear in Soil Taxonomy classification.