Contribution of thiols and new thiophenols to the ageing bouquet of red wines by using the polarised sensory positioning approach

Abstract

The bouquet of aged wines is a complex sensory concept that is strongly associated with a balance of fresh fruit notes, complemented by empyreumatic notes, toast, mint, and truffle. In more recent studies, the presence of sulphur compounds associated with empyreumatic, grilled meat or smoky aromas has been described in old red wines. The objective of this work was to determine the sensory contribution of these empyreumatic sulphur compounds to the ageing bouquet perception of red wines. The first step was to quantify these thiols in wines and to calculate their odour activity based on individual perception thresholds. The concentration levels were ranged from some ng/L to few hundreds ng/L. Some of them (5-methyl-2-furfurylthiol, 2,5-dimethylfuran-3-thiol, 1-phenylethanethiol, o-thiocresol and thioguaiacol) can be found in old red wines at higher concentrations than their perception threshold with OAV > 1 (from 1.9 to 61.4). To further determine their sensory impact on the aroma of old red wines, we applied a polarised sensory positioning (PSP). This approach is interesting for comparing complex samples with small differences. The pivotal step in this approach is the selection of references, termed “poles”. In the context of our study, we selected three poles (P) corresponding to: P1, a young wine developing fresh fruity aromas; P2, an old red wine (2006) without bouquet and without oxidation; and P3, an old red wine (2006) characterised by the empyreumatic notes of an ageing bouquet. The sulphur compounds: thioguaiacol, o-thiocresol, 5-methylfurfurylthiol and 2,5-dimethyl-2-furanthiol associated with these empyreumatic notes were quantified. Highest levels were detected in the wine P3, but remaining below their perception threshold. To evaluate whether these compounds contribute to the expression of empyreumatic notes in the ageing bouquet, their concentrations in P1 and P2 were adjusted to the levels measured in P3. Sensory analysis reveals a change in their aromatic profile, bringing it closer to the reference wine characterized by an ageing bouquet, P3. The supplementation of these compounds at low (infraliminar) concentrations modifies the aromatic balance, likely through perceptual interactions that contribute to the perception and complexity of the bouquet of aged Cabernet Sauvignon red wines. Finally, this new sensory approach helped to validate the contribution of new sulphur compounds to the ageing bouquet.

References

Suhas, E., Shinkaruk, S., & Pons, A. (2024). Optimizing the identification of thiols in red wines using new oak-wood accelerated reductive treatment. Food Chemistry, 437, 137859

Teillet, E., Thomas, A., & Demonteil, L. (2023). Chapter 11—Polarized sensory positioning (PSP) as a sensory profiling technique. In J. Delarue & J. B. Lawlor (Éds.), Rapid Sensory Profiling Techniques (Second Edition) (Second Edition, p. 237‑256).