Oenological performances of new white grape varieties

Abstract

The wine industry works to minimize pesticides and adapt to climate change. Breeding programs have developed disease-resistant grape varieties, particularly against downy and powdery mildew, to minimize pesticide applications [1]. However, their enological potential remains underexplored. This study compares disease-resistant white grape varieties with traditional cultivars by evaluating various enological parameters. Ten musts were prepared from seven grape varieties, including resistant (Voltis, Souvignier Gris, Sauvignac, and Floreal) and traditional (Chardonnay, Sauvignon, and Viognier) varieties, from Atlantic and Mediterranean climates. Fermentation was conducted at laboratory scale with online CO₂ monitoring and two yeast strains: Zymaflore X5 and Anchor Alchemy II. Wines were analyzed for metabolites from central carbon metabolism (MCCM), varietal thiols (3SH, A3SH), fermentative aromas (ethyl esters, acetate esters and higher alcohols), and phenolic compounds (hydroxybenzoic acids, hydroxycinnamic acids, flavanols and flavonols) using HPLC-UV-IR, UHPLC-MS/MS [2], GC-MS [3], and UHPLC-HRMS [4], respectively. Multivariate statistical analysis was applied. For the principal component analysis (PCA) of all variables, the PC1 axis (32.7%) primarily drove varietal differentiation, influenced mainly by phenolic compounds, while the PC2 (14.5%) reflected the yeast effect, driven by aromas, MCCM, varietal thiols, and fermentation kinetics. Souvignier Gris grouped with Sauvignon samples partly due to its higher abundance in varietal thiols, suggesting enological similarities possibly linked to genetic proximity. Sauvignac, Voltis, and a Floreal sample showed some proximity to Souvignier Gris, with the first influenced by ethyl esters and the others by varietal thiols. In contrast, the second Floreal sample exhibited opposite behavior to that of the first, possibly due to differences in their geographic origins. PCA of aromas and varietal thiols (PC1: 37.7%, PC2: 17.8%) showed a sample separation trend based on grape varieties and yeast strains. Regardless of the yeast strain, Souvignier Gris exhibited the same clustering behavior with Sauvignon samples as in the global analysis, influenced by 3SH and ethyl lactate. The other samples showed a more dispersed behavior. The heat map of 19 phenolic compounds showed clear clustering of each wine sample, independent of yeast strain. Sauvignac (genetically related to Sauvignon) and, to a lesser extent, Souvignier Gris, clustered with Sauvignon samples, and these varieties were the least abundant in phenolic compounds. Conversely, the Floreal samples clustered together but were separated from Voltis, despite their genetic similarity. They also had higher levels of many compounds, belonging to the different phenolic families, than Voltis. This work highlights the enological potential of disease-resistant white grape varieties. It identified key enological criteria (phenolic and aroma compounds) for assessing these varieties. Souvignier Gris and Sauvignac emerged as potential alternatives to Sauvignon, while Floreal and Voltis may still offer valuable attributes. Further research with a larger sample set is necessary, and this approach can aid breeding programs by integrating enological performance with genetic and agronomic criteria.

References

[1] Duley, G.; Ceci, A. T.; Longo, E.; Boselli, E. Comprehensive Reviews in Food Science and Food Safety (2023), 22(4), 2591.

[2] Roland, A.; Delpech, S.; Dagan, L.; Ducasse, M.-A.; Cavelier, F.; Schneider, R. Journal of Chromatography A (2016), 1468, 154.

[3] Mouret, J. R.; Perez, M.; Angenieux, M.; Nicolle, P.; Farines, V.; Sablayrolles, J. M. Food and Bioprocess Technology (2014), 7(5), 1235.

[4] Flores, D.; Meudec, E.; Dias, A. L. D. S.; Sommerer, N. Methods and Protocols (2024), 7(5), 82.