IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 The effect of sulfur compounds on the formation of varietal thiols in Sauvignon Blanc and Istrian Malvasia wines

The effect of sulfur compounds on the formation of varietal thiols in Sauvignon Blanc and Istrian Malvasia wines

Abstract

Varietal thiols 3-sulfanylhexan-1-ol (3SH), 3-sulfanylhexyl acetate (3SHA) and 4-methyl-4-sulfanylpentan-2-one (4SMP) are essential for fruity aromas of Sauvignon Blanc wines. The concentration of varietal thiols in wines was thought to be related to the concentration of their precursors in grapes, however only a small proportion of precursors are released to varietal thiols during fermentation. New findings suggested that specific grape juice metabolites could significantly impact on the development of three major varietal thiols and other aroma compounds of Sauvignon Blanc wines. Among them, elemental sulfur and hydrogen sulfide indicated a positive role on the formation of varietal thiols during vinification (Araujo et al., 2016; Harsch et al., 2013). This research aimed to investigate the addition of different sources of sulfur in grape juice on formation of 3SH, 3SHA, 4SMP and benzene methanethiol (BM) in Sauvignon Blanc and Istrian Malvasia wines. Istrian Malvasia (Vitis vinifera L.) is a local grapevine variety which sometimes aromatically resemble on Sauvignon Blanc.Pressed grape juice was settled overnight and sampled from tank for microfermentations. Additions of different sulfur compounds in 700 mL of juice were performed just before yeast inoculation in four replicates each: (1) control – no addition, (2) addition of reduced glutathione (GSH) (20 and 50 mg/L), (3) addition of methionine (10 and 20 mg/L), (4) addition of cysteine (20 and 40 mg/L), (5) addition of elemental sulfur (5 and 10 mg/L) and (6) addition of  sodium hydrosulfide hydrate (1 and 10 mg/L). Fermentations were performed with Saccharomyces cerevisae (X5, Laffort, France) in 750 mL dark glass bottles at 18-20 °C. After fermentation, 50 mg/L SO2 was added, wines were settled, racked, and stored at -20 °C until analyses. Varietal thiols were analysed by GC-MS/MS (Schimadzu, TQ8050) using the modified method as described (Šuklje et al., 2013).Sauvignon Blanc wines with the addition of 10 mg/L NaSH·xH2O (which releases hydrogen sulfide) had significant higher concentration of 3SH and 3SHA compared to control and other treatments. Istrian Malvasia wines with the addition of 10 mg/L NaSH·xH2O had significant higher concentrations of 3SH but there were no significant differences in 3SHA.  The addition of elemental sulfur increased 3SH and 3SHA in both varieties, however not significantly. Addition of sulphur compounds in our study had no effect on concentration of 4MMP and BM in Sauvignon Blanc or Istrian Malvasia wines. On the other hand, the additions of GSH and cysteine resulted in significantly lower formation of 3SH and 3SHA in Sauvignon Blanc wines in comparison to control and other additions. The latter finding is compliant with the study on model wines by Alegre et al. (2019).Modifying sulfur source composition in grape juice showed some significant changes in concentration of 3SH in both Sauvignon Blanc and Istrian Malvasia wines.

References

Araujo D. L., Vannevel S., Buica A., Callerot S., Fedrizzi B., Kilmartin A. P., du Toit J. W. 2016. Indications of the prominent role of elemental sulfur in the formation of the varietal thiol 3-mercaptohexanol in Sauvignon blanc wine, Food Research International, 98, 79-86.

DOI:

Publication date: June 27, 2022

Issue: IVAS 2022

Type: Poster

Authors

Vanzo Andreja1, Alenka Mihelčič1, Katja Šuklje1, Klemen Lisjak1

1 Agricultural Institute of Slovenia

Contact the author

Keywords

sulfur compounds, grape juice, varietal thiols, Sauvignon Blanc, Istrian Malvasia

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"...

Effects of organic mulches on the soil environment and yield of grapevine

Farming management practices aiming at conserving soil moisture have been developed in arid and semiarid-areas facing water scarcity problems. Organic mulching is an effective method to manipulate the crop-growing microclimate increasing crop yield by controlling soil temperature, and retaining soil moisture by reducing soil evaporation. In this sense, the effectiveness of different organic mulching materials (straw mulch and grapevine pruning debris) applied within the row of a vineyard was evaluated on the soil and on the vine in a Tempranillo vineyard located in La Rioja (Spain). Organic mulches were compared with a traditional bare soil management technique (based on the use of herbicides to avoid weed incidence). Mulching coverages favourably influenced the soil water retention throughout all the grapevine vegetative cycle. However, the soil-moisture variation was not the same under different mulching materials, being the straw mulch (SM) the one that retained more water in comparison with grapevine pruning debris (GPD) based-cover. The changes of soil moisture in the upper surface layer (0–10 cm) were highly dynamic, probably due to water vapour fluxes across the soil-atmospheric interface. However, both, SM and GPD reduced these fluctuations as compared with bare soils. A similar trend occurred with soil temperature. Both organic mulches altered soil temperature in comparison with bare soil by reducing soil temperature in summer and raising it in winter. Moreover, the same buffering effect for the temperature on the covered soil also remains in the deeper layers. To conclude, we could see that organic mulching had a positive impact on soil-moisture storage and soil temperature and the extent of this effect depends on the type of mulching materials. These changes led to higher rates of photosynthesis and stomatal conductivity compared to bare soils, also favouring crop growth and grape yields.

Protected Designation of Origin (D.P.O.) Valdepeñas: classification and map of soils

The objective of the work described here is the elaboration of a map of the different types of vineyard soils that to guide the famers in the choice of the most productive vine rootstocks and varieties. 90 vineyard soils profiles were analysed in the entire territory of the Origen Denominations of Valdepeñas. The sampling was carried out in 2018 (June to October) by making a sampling grid, followed by photointerpretation and control in the field. The studied soils can be grouped into 9 different soil types (according to FAO 2006 classification): Leptosols, Regosols, Fluvisols, Gleysols, Cambisols, Calcisols, Luvisols and Anthrosols. A map showing the soil distribution with different type of soils has been made with the ArcGIS program. Regarding to the choice of rootstock, Calcisoles are soils with a high active limestone content, so the rootstocks used in these soils must be resistant to this parameter; Luvisols are deep soils with high clay content, so they will support vigorous rootstocks. Because the cartographic units are composed of two or more subgroups, with are associated in variable proportions, 9 different soil associations have been established; Unit 1: Leptosols, Cambisols and Luvisols (80%, 15% and 5% respectively); Unit 2: Cambisols with Regosols and Luvisols (40%, 30% and 30% respectively); Unit 3: Cambisols and Gleysols with Regosols (40%, 40% and 20% respectively); Unit 4: Regosols with Cambisols, Leptosols and Calcisols (40%, 30%, 15% and 15% respectively); Unit 5: Cambisols, Leptosols, Calcisols and Regosols (25% each of them); Unit 6: Luvisols with Cambisol and Calcisols (80%, 10% and 10% respectively); Unit 7: Luvisols and Calcisols with Cambisols (40%, 40% and 20% respectively); Unit 8: Calcisols with, Cambisols and Luvisols (80%, 10% and 10% respectively); Unit 9: Anthrosols. These study allow to elaborate the first map of vineyard soils of this Protected Designation of Origin in Castilla-La Mancha.

‘Cabernet Sauvignon’ (Vitis vinifera L.) berry skin flavonol and anthocyanin composition is affected by trellis systems and applied water amounts

Trellis systems are selected in wine grape vineyards to mainly maximize vineyard yield and maintain berry quality. This study was conducted in 2020 and 2021 to evaluate six commonly utilized trellis systems including a vertical shoot positioning (VSP), two relaxed VSPs (VSP60 and VSP80), a single high wire (SH), a high quadrilateral (HQ), and a guyot (GY), combined with three levels of irrigation regimes based on different crop evapotranspiration (ETc) replacements, including a 25% ETc, 50% ETc, and 100% ETc. The results indicated SH yielded the most fruits and accumulated the most total soluble solids (TSS) at harvest in 2020, however, it showed the lowest TSS in the second season. In 2020, SH and HQ showed higher concentrations in most of the anthocyanin derivatives compared to the VSPs. Similar comparisons were noticed in 2021 as well. SH and HQ also accumulated more flavonols in both years compared to other trellis systems. Overall, this study provides information on the efficacy of trellis systems on grapevine yield and berry flavonoid accumulation in a currently warming climate.

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.