Macrowine 2021
IVES 9 IVES Conference Series 9 Phytosterols and ergosterol role during wine alcoholic fermentation for 27 Saccharomyces cerevisiae strains

Phytosterols and ergosterol role during wine alcoholic fermentation for 27 Saccharomyces cerevisiae strains

Abstract

Sterols are a class of the eukaryotic lipidome that is essential for the maintenance of the cell membrane integrity and their good functionality (Daum et al., 1998). During alcoholic fermentation, they ensure yeast growth, metabolism and viability, as well as resistance to osmotic stress and ethanol inhibition (Mannazzu et al., 2008). Musts clarified in excess lead to the loss of solid particles rich in sterols, resulting in sluggish and stuck fermentations (Casalta et al., 2013). Two sterol sources can support yeasts to adapt to fermentation stress conditions: ergosterol, produced by yeast in aerobic conditions, and phytosterols, plant sterols found in grape musts imported by yeasts in the absence of oxygen (Nes, 1987). Little is known about the physiological impact of the assimilation of phytosterols in comparison to ergosterol and the influence of sterol nature on fermentation kinetics parameters. Moreover, studies done until today analyzed a limited number of yeasts strains. For this reason, the aim of this work is to compare the fermentation performances of 27 Saccharomyces cerevisiae strains with phytosterols and ergosterol on two conditions: sterol stress (sterol starvation) and osmotic stress (the most common stress during fermentation due to high concentrations of sugars).Experiments were performed in 300 mL fermenters without oxygen. Fermentation kinetics were monitored continuously through CO2 production in order to obtain parameters, such as the maximum fermentation rate (Vmax) or total CO2 production. Cell count and cell viability were measured around 80% of fermentation progress. Central carbon metabolism (CCM) metabolites (acetate, glycerol, succinate and residual sugars) were quantified at the end of fermentation.Principal Component Analysis with biological, kinetic and CCM variables revealed the huge phenotype diversity of strains in this study. Analysis of variance (ANOVA) indicated that both the strain and the nature of sterol explained the differences on yeast performances in fermentation. It should be noted that cellular viability is a key parameter in both sterol and osmotic stress. Indeed, strains with a high viability at the end of the fermentation finished fermenting earlier. Finally, ergosterol allowed a better completion of fermentation in both stress conditions tested.These results highlighted the role of sterols in wine alcoholic fermentation to ensure yeast growth and avoid sluggish or stuck fermentations. Interestingly, sterol nature affected yeast viability, biomass, kinetics parameters and biosynthesis of CCM metabolites

DOI:

Publication date: September 7, 2021

Issue: Macrowine 2021

Type: Article

Authors

Giovana Girardi Piva 

SPO, Univ Montpellier, INRAE, Institut Agro, Montpellier, France,Jean-Roch MOURET (SPO, Univ Montpellier, INRAE, Institut Agro, Montpellier, France)  Virginie GALEOTE (SPO, Univ Montpellier, INRAE, Institut Agro, Montpellier, France) Jean-Luc LEGRAS (SPO, Univ Montpellier, INRAE, Institut Agro, Montpellier, France) Erick CASALTA (SPO, Univ Montpellier, INRAE, Institut Agro, Montpellier, France) Anne ORTIZ-JULIEN (Lallemand SAS, Blagnac, France)

Contact the author

Keywords

wine yeast, sterol starvation, osmotic stress, yeast membrane, alcoholic fermentation

Citation

Related articles…

MONOSACCHARIDE COMPOSITION AND POLYSACCHARIDE FAMILIES OF LYOPHILISED EXTRACTS OBTAINED FROM POMACES OF DIFFERENT WHITE GRAPE VARIETIES

The recovery of bioactive compounds from grape and wine by-products is currently an important and necessary objective for sustainability. Grape pomace is one of the main by-products and is a rich source of some bioactive compounds such as polyphenols, polysaccharides, fatty acids, minerals and seed oil. Polysaccharides contained in the grape cell wall can be rhamnogalacturonans type II (RG-II), polysaccharides rich in arabinose and galactose (PRAG), mannoproteins (MP), homogalacturonans (HG) and non pectic polysaccharides (NPP).

Impact of drought stress on concentration and composition of wine proteins in Riesling

Protein haze in white wines is a major technological and economic problem of the wine industry. Field tests were carried out in steep slope vineyards planted with Riesling grapes over 3 dry growing seasons to study the effect of drought stress on the concentration of proteins in the resulting wines. Plots suffering from drought stress were compared with surrounding drip irrigated plots. Riesling grapes were processed into wines by conventional procedures. Protein amounts of the isolated wine colloids of the stressed samples were always higher than those of the watered samples(mean watered 13.8 ± 0.44, mean stressed 17.4 ± 0.40 g 100 g-1). As a consequence, higher bentonite doses were needed to achieve protein haze stability of the drought stressed treatments.

Classification of “Valpolicella Superiore” wines in relation to aromatic composition: influence of geographical origin, vintage and aging

The Valpolicella appellation, mainly known for Amarone and Ripasso, is experiencing growing interest in Valpolicella Superiore (VS), a lighter red wine aligning with consumer demand. However, anecdotal evidence suggests different stylistic interpretations of VS, potentially causing consumer confusion.

Similarities among wine aromas and landscape scents around the vineyard in five Mediterranean sites

We compared 68 aroma compounds in wines from 5 vineyards in order to see similarities among the wine aroma and the scent of some of the main native plants from the respective vineyards.

New satellite-based sampling protocols for grapevine nutrient monitoring

Extension specialists often recommend nutrient monitoring through leaf blade or petiole sampling twice a season for each vineyard block. However, due to the time and labor required to collect a large, random sample, many growers complete the task infrequently or incorrectly. Readily available remote sensing images capture the vineyard variability at both spatial and temporal scales, which can capture canopy and soil variability and be used to guide growers to representative sampling locations.