 IVES 9 IVES Conference Series 9 Macrowine 9 Macrowine 2021 9 Grapevine diversity and viticultural practices for sustainable grape growing 9 Evaluation of glutathione content in four white varieties in the d.o. Ca. Rioja (Spain)

Evaluation of glutathione content in four white varieties in the d.o. Ca. Rioja (Spain)

Abstract

AIM: Glutathione is a tripeptide that is mainly found in reduced form in grapes. It generates during the maturation of the grape, increasing significantly after veraison [1]. It plays a relevant role in the prevention of oxidative processes due to its high antioxidant activity. Its content in the grape is influenced by many factors (variety, vintage, cultural practices, nitrogen nutrition …) [2]. In musts and wines, it undergoes modifications due to oxygen exposure, tyrosinase activity, maceration time, pressing, yeast strain…[3]. The aim of this work was to evaluate the content of glutathione in the grape of four white varieties: Tempranillo Blanco, Maturana Blanca, Garnacha Blanca and Viura.

METHODS: The study was carried out during three seasons (2017, 2018 and 2019) in a vineyard located in the D.O.Ca. Rioja (Spain). On the other hand, the influence of different vineyard locations on the content of this compound in the indicated varieties was also analyzed. Glutathione determination was carried out by HPLC by automatic derivatization in precolumn with OPA. The previous extraction in the grape was carried out with HCl/EDTA [4].

RESULTS: The results obtained showed important varietal differences in the glutathione content of the grape in the white varieties studied. The highest concentration was obtained in the Tempranillo Blanco variety, although without significant differences in comparison to Viura, while the lowest levels corresponded to Maturana Blanca and Garnacha Blanca. Also, the characteristics of the vintage also influenced its concentration, although the varietal differences were maintained. The location of the vineyard showed a variable effect depending on the vinifera, and the characteristics of the vintage in the case of Tempranillo Blanco.

CONCLUSIONS

These results confirm that the variety is one of the most influential factors in the glutathione content in grapes. Tempranillo Blanco has high levels of this compound, which can help preserve the quality of your wines.

DOI:

Publication date: September 2, 2021

Issue: Macrowine 2021

Type: Article

Authors

Juana Martinez

Instituto De Ciencias De La Vid Y Del Vino (Gobierno De La Rioja, Csic, Universidad De La Rioja),Laura, Alti, Instituto De Ciencias De La Vid Y Del Vino (Gobierno De La Rioja, Csic, Universidad De La Rioja) Sara, Garcia, Instituto De Ciencias De La Vid Y Del Vino (Gobierno De La Rioja, Csic, Universidad De La Rioja) Elisa, Baroja, Instituto De Ciencias De La Vid Y Del Vino (Gobierno De La Rioja, Csic, Universidad De La Rioja)

Contact the author

Keywords

glutathione, grape, white varieties, location, season

Citation

Impact of varying ethanol and carbonation levels on the odor threshold of 1,1,6-trimethyl-1,2-dihydronaphtalene (petrol off-flavor) and role of berry size and Riesling clones

1,1,6-trimethyl-1,2-dihydronaphtelene (TDN) evokes the odor of “petrol” in wine, especially in the variety Riesling. Increasing UV-radiation due to climate change intensifies formation of carotenoids in the berry skins and an increase of TDN-precursors1. Exploring new viticultural and oenological strategies to limit TDN formation in the future requires precise knowledge of TDN thresholds in different matrices. Thresholds reported in the literature vary substantially between 2 µg/L up to 20 µg/L2,3,4 due to the use of different methods. As Riesling grapes are used for very different wine styles such as dry, sweet or sparkling wines, it is essential to study the impact of varying ethanol and carbonation levels.

Future projections for chilling and heat forcing for European vineyards

Aims: The aims of this study were: (1) to compute recent-past thermal conditions over European vineyards, using state-of-the art bioclimatic indices: chilling portions and growing degree hours; (2) to compute future changes of these thermal conditions using a large ensemble of high-resolution climate models.

INFLUENCES OF SO2 ADDITION AND STORAGE CONDITIONS IN THE DETERMINATION OF MEAN DEGREE OF POLYMERIZATION OF PROANTHOCYANIDINS IN AGED RED WINES

The structural diversity is one of the most remarkable characteristics of proanthocyanidins (PA). Indeed, PA in wines may vary in the B-ring and C-ring substitutes, the C-ring stereochemistry, the degree of polymerization (DP) and the linkage between the monomers. Knowing in detail the structural characteristics of the PA of a wine can help us to understand and modulate several sensorial characteristics of the wine, such as color, antioxidant properties, flavor, and mouthfeel properties. In the last years was discovered and confirmed the presence of sulfonated monomeric and oligomeric flavan-3-ols in wine [1], as well as was pointed out their importance in wine quality [1,2].

Role of anthocyanins and copigmentation in flavonol solubility in red wines

Over the last years, due to climate change, several red wines, such as the Sangiovese wines, have been often subjected to loss of clarity due to the formation of deposits of fine needle-shaped crystals. This phenomenon turned out to be due to an excess of quercetin (Q) and its glycosides (Q-Gs) in wines. These compounds are synthesized to a large extent when grapes are excessively exposed to UVB radiations in vineyards[1]. Unfortunately, it is not easy to predict the degree of Q precipitation because its solubility strongly depends on the wine and matrix composition[2].

Grapevine rootstock field evaluation under drought and saline condition in California

Climate change impacts grape production worldwide and in California drought and salinity became increasingly challenging for grape growers to maintain sustainable production and fruit quality.