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…

A predictive model of spatial Eca variability in the vineyard to support the monitoring of plant status

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.19.4" _module_preset="default" module_text_align="center" module_font_size="16px" text_orientation="center"...

Analysis of some environmental factors and cultural practices that affect the production and quality of the Manto Negro, Callet and Prensal Blanc varieties

45 non irrigated vineyards distributed in the DO (Denomination) Pla i Llevant de Mallorca and the DO Binissalem Mallorca were used to investigate the characteristics of production and quality and their relationships certain environmental factors and cultural practices. The grape varieties investigated are autochthonous to the island of Mallorca, Manto Negro and Callet as red and Prensal Blanc as white. All plants were measured for four consecutive years in the main production and quality parameters. Among the environmental factors, the type of soil has been studied, more specifically its water retention capacity, the planting density, the age of the vineyard and the level of viral infection. The presence or absence of virus seems to have no effect on any component studied in the varieties studied. For the white variety Prensal Blanc age is negatively correlated with production and the number of bunches, nevertheless it does not cause any effect on the required quality parameters. However, for the red varieties Callet and Manto Negro, the age of the plantation is the variable that best correlates with the quality parameters, therefore the old vines should be the object of preservation by the viticulturists and winemakers in order to guarantee its contribution to the quality of the wines made with these varieties.

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.

VINIoT: Precision viticulture service for SMEs based on IoT sensors network

The main innovation in the VINIoT service is the joint use of two technologies that are currently used separately: vineyard monitoring using multispectral imaging and deployed terrain sensors. One part of the system is based on the development of artificial intelligence algorithms that are feed on the images of the multispectral camera and IoT sensors, high-level information on water stress, grape ripening status and the presence of diseases. In order to obtain algorithms to determine the state of ripening of the grapes and avoid losing information due to the diversity of the grape berries, it was decided to work along the first year 2020 at berry scale in the laboratory, during the second year at the cluster scale and on the last year at plot scale. Different varieties of white and red grapes were used; in the case of Galicia we worked with the white grape variety Treixadura and the red variety Mencía. During the 2020 and 2021 campaigns, multispectral images were taken in the visible and infrared range of: 1) sets of 100 grapes classifying them by means of densimetric baths, 2) individual bunches. The images taken with the laboratory analysis of the ripening stage were correlated. Technological maturity, pH, probable degree, malic acid content, tartaric acid content and parameters for assessing phenolic maturity, IPT, anthocyanin content were determined. It has been calculated for each single image the mean value of each spectral band (only taking into account the pixels of interest) and a correlation study of these values with laboratory data has been carried out. These studies are still provisional and it will be necessary to continue with them, jointly with the training of the machine learning algorithms. Processed data will allow to determine the sensitivity of the multispectral images and select bands of interest in maturation.

Climate ethnography and wine environmental futures

Globalisation and climate change have radically transformed world wine production upsetting the established order of wine ecologies. Ecological risks and the future of traditional agricultural systems are widely debated in anthropology, but very little is understood of the particular challenges posed by climate change to viticulture which is seen by many as the canary in the coalmine of global agriculture. Moreover, wine as a globalised embedded commodity provides a particularly telling example for the study of climate change having already attracted early scientific attention. Studies of climate change in viticulture have focused primarily on the production of systematic models of adaptation and vulnerability, while the human and cultural factors, which are key to adaptation and sustainable futures, are largely missing. Climate experts have been unanimous in recognising the urgent need for a better understanding of the complex dynamics that shape how climate change is experienced and responded to by human systems. Yet this call has not yet been addressed. Climate ethnography, coined by the anthropologist Susan Crate (2011), aims to bridge this growing disjuncture between climate science and everyday life through the exploration of the social meaning of climate change. It seeks to investigate the confrontation of its social salience in different locations and under different environmental guises (Goodman 2018: 340). By understanding how wine producers make sense of the world (and the environment) and act in it, it proposes to focus on the co-production of interdisciplinary knowledge by identifying and foreshadowing problems (Goodman 2018: 342; Goodman & Marshall 2018). It seeks to offer an original, transformative and contrasted perspective to climate change scenarios by investigating human agency -individual or collective- in all its social, political and cultural diversity. An anthropological approach founded on detailed ethnographies of wine production is ideally placed to address economic, social and cultural disruptions caused by the emergence of these new environmental challenges. Indeed, the community of experts in environmental change have recently called for research that will encompass the human dimension and for more broad-based, integrated through interdisciplinarity, useful knowledge (Castree & al 2014). My paper seeks to engage with climate ethnography and discuss what it brings to the study of wine environmental futures while exploring the limitations of the anthropological environmental approach.