IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Exogeneous C-S lyase enzyme, a potential tool for thiol enhancement in wine or beer?

Exogeneous C-S lyase enzyme, a potential tool for thiol enhancement in wine or beer?

Abstract

Varietal thiols are considered for years as key aroma compounds in many wines. Their main origin is the cleavage during alcoholic fermentation of S-conjugate precursors present in grapes and musts, even if the levels of precursors already identified struggle to completely explain the levels of thiols found in wine.
In this bioconversion process, yeast is the key since the cleavage of thiol precursors has been demonstrated to be due to the internal C-S lyase activity of the yeast strains. Whatever the intrinsic capacity of the yeast and the regulation mechanisms identified for the transportation of thiol precursor into the cell, the conversion yield remains very low, estimated in most cases at 1%. In this context, the use of exogenous C-S lyases could be an alternative option to reveal a larger part of the thiol aroma.
Our study focused on the characterization of a recombinant C-S lyase model obtained by from Lactobaccilus delbrueckii subsp. bulgaricus, expressed in E. coli [1] to investigate the possibility of using such enzymes in different matrices such as wine, beer or directly hops, known to be rich in thiol precursors.
A spectrophotometric method was developed for the quantification of the C-S lyase activity, using commercially available S-4-nitrophenyl-L-cysteine (Cys(4NP)). This method was then used to study the specificity of substrate and potential competitor recognition, still using Cys(4NP) but also G-4NP, Cys(4NP)-Gly and γGlu-Cys(4NP) conjugates, which were specifically synthesized in our lab, based on our previous results [2].
The C-S lyase we used was able to cleave efficiently Cys(4NP), but not glutathione and dipeptide 4NP-S-conjugates. As expected, pH emerged as a key parameter: no reaction at wine pH (2.8-3.5), low activity at beer pH (4.5-5.6) and > 80% of activity at pH above 6. Assays with N-Ac-Cys(4NP) confirmed that a free amine group on the substrate was compulsory for recognition by the enzyme and subsequent cleavage of the substrate. Free cysteine has also been demonstrated to compete with Cys(4NP) resulting in a dramatic decrease in conversion efficiency.
These first results documented the possibility of using such enzyme in the different matrices, highlighting the constraints for the subsequent identification of C-S lyase more suitable to wine or beer productions

References

[1] Allegrini, A.; Astegno, A.; La Verde, V.; Dominici, P. Characterization of C-S lyase from Lactobacillus delbrueckii subsp. bulgaricus ATCC BAA-365 and its potential role in food flavor applications. J. Biochem. 2017, 61, 349−360.
[2] Bonnaffoux, H., Roland, A., Rémond, E., Delpech, S., Schneider, R., & Cavelier, F. (2017). First identification and quantification of S-3-(hexan-1-ol)-γ-glutamyl-cysteine in grape must as a potential thiol precursor, using UPLC-MS/MS analysis and stable isotope dilution assay. Food Chemistry, 237, 877–886.

DOI:

Publication date: June 27, 2022

Issue: IVAS 2022

Type: Poster

Authors

Clerat Luigi1, Vives Eric1, Cavelier Florine2, Remond Emmanuelle2 and Schneider Rémi3

1PhyMedExp – Physiologie & médecine expérimentale du Cœur et des Muscles [U 1046]
2Institut des biomolécules Max Mousseron (IBMM) – UMR-5247 – CNRS
3Oenobrands Montpellier FR

Contact the author

Keywords

C-S lyase, varietal thiol precursors, wine aroma, S-conjugates

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

The interplay between grape ripening and weather anomalies – A modeling exercise

Current climate change is increasing inter- and intra-annual variability in atmospheric conditions leading to grapevine phenological shifts as well altered grape ripening and composition at ripeness. This study aims to (i) detect weather anomalies within a long-term time series, (ii) model grape ripening revealing altered traits in time to target specific ripeness thresholds for four Vitis vinifera cultivars, and (iii) establish empirical relationships between ripening and weather anomalies with forecasting purposes. The Day of the Year (DOY) to reach specific grape ripeness targets was determined from time series of sugar concentrations, total acidity and pH collected from a private company in the period 2009-2021 in North-Eastern Italy. Non-linear models for the DOY to reach the specified ripeness thresholds were assessed for model efficiency (EF) and error of prediction (RMSE) in four grapevine cultivars (Merlot, Cabernet Sauvignon, Glera and Garganega). For each vintage and cultivar, advances or delays in DOY to target specified ripeness thresholds were assessed with respect to the average ripening dynamics. Long-term meteorological series monitored at ground weather station by means of hourly air temperature and rainfall data were analyzed. Climate statistics were obtained and for each time period (month, bimester, quarter and year) weather anomalies were identified. A linear regression analysis was performed to assess a possible correlation that may exist between ripening and weather anomalies. For each cultivar, ripeness advances or delays expressed in number of days to target the specific ripening threshold were assessed in relation to registered weather anomalies and the specific reference time period in the vintage. Precipitation of the warmest month and spring quarter are key to understanding the effect of climate change on sugar ripeness. Minimum temperatures of May-June bimester and maximum temperatures of spring quarter best correlate with altered total acidity evolution and pH increment during the ripening process, respectively.

Biodiversity in the vineyard agroecosystem: exploring systemic approaches

Biodiversity conservation and restoration are essential for guarantee the provision of ecosystem services associated to vineyard agroecosystem such as climate regulation trough carbon sequestration and control of pests and diseases. Most of published research dealing with the complexity of the vineyard agroecosystems emphasizes the necessity of innovative approaches, including the integration of information at different temporal and spatial scales and development of systemic analysis based on modelling. A biodiversity survey was conducted in the Franciacorta wine-growing area (Lombardy, Italy), one of the most important Italian wine-growing regions for sparkling wine production, considering a portion of the territory of 112 ha. The area was divided into several Environmental Units (EUs), defined as a whole vineyard or portion of vineyard homogenous in terms of four agronomic characteristics: planting year, planting density, cultivar, and training system. In each EU a set of compartments was identified and characterised by specific variables. The compartments are meteorology, morphology (altitude, slope, aspect, row orientation, and solar irradiance), ecological infrastructures and management. The landscape surrounding EU was also characterised in terms of land-use in a buffer zone of 500 m. For each component a specific methodology was identified and applied. Different statistical approaches were used to evaluate the method to integrate the information related to different compartments within the EU and related to the buffer zone. These approaches were also preliminarily evaluated for their ability to describe the contribution of biodiversity and landscape components to ecosystem services. This methodological exploration provides useful indication for the development of a fully systemic approach to structural and functional biodiversity in vineyard agroecosystems, contributing to promote a multifunctional perspective for the all wine-growing sector.

An analytical framework to site-specifically study climate influence on grapevine involving the functional and Bayesian exploration of farm data time series synchronized using an eGDD thermal index

Climate influence on grapevine physiology is prevalent and this influence is only expected to increase with climate change. Although governed by a general determinism, climate influence on grapevine physiology may present variations according to the terroir. In addition, these site-specific differences are likely to be enhanced when climate influence is studied using farm data. Indeed, farm data integrate additional sources of variation such as a varying representativity of the conditions actually experienced in the field. Nevertheless, there is a real challenge in valuing farm data to enable grape growers to understand their own terroir and consequently adapt their practices to the local conditions. In such a context, this article proposes a framework to site-specifically study climate influence on grapevine physiology using farm data. It focuses on improving the analysis of time series of weather data. The analytical framework includes the synchronization of time series using site-specific thermal indices computed with an original method called Extended Growing Degree Days (eGDD). Synchronized time series are then analyzed using a Bayesian functional Linear regression with Sparse Steps functions (BLiSS) in order to detect site-specific periods of strong climate influence on yield development. The article focuses on temperature and rain influence on grape yield development as a case study. It uses data from three commercial vineyards respectively situated in the Bordeaux region (France), California (USA) and Israel. For all vineyards, common periods of climate influence on yield development were found. They corresponded to already known periods, for example around veraison of the year before harvest. However, the periods differed in their precise timing (e.g. before, around or after veraison), duration and correlation direction with yield. Other periods were found for only one or two vineyards and/or were not referred to in literature, for example during the winter before harvest.

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.

Extreme canopy management for vineyard adaptation to climate change: is it a good idea?

Climate change constitutes an enormous challenge for humankind and for all human activities, viticulture not being an exception. Long-term strategic changes are probably needed the most, but growers also need to deal with short-term changes: summers that are getting progressively warmer, earlier harvest dates and higher pH in musts and wines. In the last 10-15 years, a relevant corpus of research is being developed worldwide in order to evaluate to which extent extreme canopy management operations, aimed at reducing leaf area and, thus, limiting the source to sink ratio, could be useful to delay ripening. Although extreme canopy management can result in relevant delays in harvest dates, longer term studies, as well as detailed analysis of their implications on carbohydrate reserves, bud fertility and future yield are desirable before these practices can be recommended.