Macrowine 2021
IVES 9 IVES Conference Series 9 Screening of aroma metabolites within a set of 90 Saccharomyces strains

Screening of aroma metabolites within a set of 90 Saccharomyces strains

Abstract

Currently, the main demand in the global wine market relies on products with unique flavour profiles, character, and typicity, and the metabolism of yeasts greatly influences the organoleptic properties of wines. Therefore, the natural diversity of Saccharomyces strains rises in interest over the last decade, but a large part of this phenotypic diversity remains unexplored. Moreover, the genetic basis underlying the variation in the production of flavour-active metabolites within the Saccharomyces genus remains poorly understood. The main purpose of this project is to provide a better understanding of how the synthesis of these flavour-active compounds is modulated at genetic level, aiming to identify genes with specific functions in the metabolism of yeasts. This information will be obtained through the generation of novel hybrids between different Saccharomyces species and the use of quantitative genetics. In this context, the first step was to assess the phenotypic diversity at the scale of Saccharomyces genus, regarding traits of industrial interest. With this aim, 90 yeast strains of all the eight species which compose the Saccharomyces clade were screened for their fermentative capacities and the production of aromas and other compounds of interest (such as glycerol or succinate). Fermentations in oenological conditions were carried out at different temperatures, monitoring the kinetic profiles and analysing the production of the main fermentation metabolites (by HPLC) as well as the production of more than 40 aroma compounds (by GC-MS). The sporulation ability of the strains, necessary for the hybridization, was also assessed. Important differences were found in the kinetic and volatile profiles of the strains, and the whole dataset provides a comprehensive picture of the phenotypic diversity within the genus Saccharomyces. This information confirms the interest in further development of genetic approaches to identify the molecular basis underlying the studied traits and opens the door for their improvement.

DOI:

Publication date: September 3, 2021

Issue: Macrowine 2021

Type: Article

Authors

Rafael Álvarez-Rafael, Sylvie DEQUIN, Edward J. LOUIS, Carole CAMARASA

UMR 1083 Sciences Pour l’Oenologie, INRAE, Montpellier SupAgro, Montpellier, France, UMR 1083 Sciences Pour l’Oenologie, INRAE, Montpellier SupAgro, Montpellier, France ,Centre of Genetic Architecture of Complex Traits, University of Leicester, Leicester, UK, UMR 1083 Sciences Pour l’Oenologie, INRAE, Montpellier SupAgro, Montpellier, France

Contact the author

Keywords

Alcoholic fermentation; genus saccharomyces; phenotypic diversity; fermentative volatile compounds

Citation

Related articles…

The potential of multispectral/hyperspectral technologies for early detection of “flavescence dorée” in a Portuguese vineyard

“Flavescence dorée” (FD) is a grapevine quarantine disease associated with phytoplasmas and transmitted to healthy plants by insect vectors, mainly Scaphoideus titanus. Infected plants usually develop symptoms of stunted growth, unripe cane wood, leaf rolling, leaf yellowing or reddening, and shrivelled berries. Since plants can remain symptomless up to four years, they may act as reservoirs of FD contributing to the spread of the disease. So far, conventional management strategies rely mainly on the insecticide treatments, uprooting of infected plants and use of phytoplasma-free propagation material. However, these strategies are costly and could have undesirable environmental impacts. Thus, the development of sustainable and noninvasive approaches for early detection of FD and its management are of great importance to reduce disease spread and select the best cultural practices and treatments. The present study aimed to evaluate if multispectral/hyperspectral technologies can be used to detect FD before the appearance of the first symptoms and if infected grapevines display a spectral imaging fingerprint. To that end, physiological parameters (leaf area, chlorophyll content and photosynthetic rate) were collected in concomitance to the measurements of plant reflectance (using both a portable apparatus and a remote sensing drone). Measurements were performed in two leaves of 8 healthy and 8 FD-infected grapevines, at four timepoints: before the development of disease symptoms (21st June); and after symptoms appearance (ii) at veraison (2nd August); at post-veraison (11th September); and at harvest (25th September). At all timepoints, FD infected plants revealed a significant decrease in the studied physiological parameters, with a positive correlation with drone imaging data and portable apparatus analyses. Moreover, spectra of either drone imaging and portable apparatus showed clear differences between healthy and FD-infected grapevines, validating multispectral/ hyperspectral technology as a potential tool for the early detection of FD or other grapevine-associated diseases.

Impact of grape ripening and post-harvest withering on must composition and fermentation kinetics

Postharvest dehydration is a widely employed technique in winemaking to enhance sugar concentration and secondary metabolites from grapes. Different grape varieties exhibit varying responses in terms of dehydration rate and the resulting chemical composition.

Intelligent article to control the internal pressure in continue in bottles

An intelligent packaging might, among others, provide information and allow monitoring of the quality of the packed product or its surrounding environment. A recent project on micro-flow wine bottles closed with aluminium screw cap and tightness liner, highlighted the importance of monitoring the internal overpressure continuously, in real-time and at least for 72 hours, since the internal pressure on the tightness liner and the micro-flow are related. Real-time and continuous measurements are not the standard methods of measurement of the overpressure, yet. The most used equipment for the determination of the pressure in wine bottle is the aphrometer, a destructive device that supplies a single value of pressure.

Remote sensing applications in viticulture: recent advances and new opportunities

Remote sensing applications in viticulture have been a research theme now for nearly two decades, becoming a valuable tool for vineyard management. Metrics produced using remotely sensed images of vineyards have yielded relationships with grape quality and yield that can help optimise vineyard performance

Organic mulches improve vine vigour, yield and physiological response in a semi-arid region

Recycled organic mulch within the row in vineyard floor management has become an interesting ecological strategy to adapt the crop to climate change consequences in semi-arid regions.
This study aimed to assess the impact of three recycled organic mulches [straw (STR), grape pruning debris (GPD), and spent mushroom compost (SMC)] and two conventional soil management practices [herbicide (HERB) and under-row tillage (TILL)] on vegetative vigour (NDVI), production (kg/plant), and physiological parameters (δ13C in grapes and leaf gas exchange during four grapevine phenology stages). Additionally, temperature and water soil parameters were collected at three soil depths. Data was collected during the 2021 and 2022 grapevine growing seasons in La Rioja, Spain.