Identification of 4-hydroxy-2-nonenal, a gamma nonalactone precursor in must and wine from Bordeaux cultivars

Abstract

Various molecular compounds are responsible for the complex mixture of fragrances that give wine its aroma. In particular, the ‘cooked fruit’ aroma found in red wines from hot and/or dry vintages or from the vinification of late harvested grapes has been intensively investigated in recent years. Lactones and especially γ-nonalactone were found to be responsible for the ‘cooked fruit’ aroma and are able to modulate its intensity. 1,2 This project aimed to study γ-nonalactone formation in order to better predict the intensity of the ‘cooked fruit’ character of wines in relation to the grape maturity. Thanks to our previous work, one precursor of γ-nonalactone has already been identified and quantified in must and wine: the 4-oxononanoic acid. 3 This work is devoted to study alternative γ-nonalactone formation pathways, especially from the products of C18 unsaturated fatty acid peroxidation. 4 That why 4-hydroxy-2-nonenal was suggested as a potential γ-nonalactone precursor. For its quantification in must and wine, the SPE-GC-MS analysis was developed, validated and applied to assaying this compound in must and wine from Bordeaux area. Then, the strereoselective biotransformation of 4-hydroxy-2-nonenal into R/S-γ-nonalactone was investigated. Finally, the impact of grape ripening and over-ripening phenomena on 4-hydroxy-2-nonenal content in must was studied.

In conclusion, our results demonstrated the presence of 4-hydroxy-2-nonenal in musts and wines and its biotransformation to γ-nonalactone during alcoholic fermentation of red grape varieties. The role of 4-hydroxy-2-nonenal as a precursor of the odorous γ-nonalactone in wine is revealed for the first time.

References

(1)         Pons, A.; Lavigne, V.; Eric, F.; Darriet, P.; Dubourdieu, D. Identification of Volatile Compounds Responsible for Prune Aroma in Prematurely Aged Red Wines. J. Agric. Food Chem. 2008, 56 (13), 5285–5290.

(2)         Allamy, L.; Darriet, P.; Pons, A. Molecular Interpretation of Dried-Fruit Aromas in Merlot and Cabernet Sauvignon Musts and Young Wines: Impact of over-Ripening. Food Chem. 2018, 266, 245–253.

(3)         Ferron, P. de; Thibon, C.; Shinkaruk, S.; Darriet, P.; Allamy, L.; Pons, A. Aromatic Potential of Bordeaux Grape Cultivars: Identification and Assays on 4-Oxononanoic Acid, a γ-Nonalactone Precursor. J. Agric. Food Chem. 2020, 68 (47), 13344–13352.

(4)         Schneider, C.; Tallman, K. A.; Porter, N. A.; Brash, A. R. Two Distinct Pathways of Formation of 4-Hydroxynonenal. J. Biol. Chem. 2001