Is Sotolon Relevant to the Aroma of Madeira Wine Blends?

Abstract

Madeira wine (MW) oxidative aging results in the formation of several key aromas. Little is still known about their odor relevance to the aroma of the most commercialized MWs. This report presents an in-depth study of the odor impact of sotolon in MW blends. First, its odor perception was estimated in MWs according to ASTM E679, testing different 3-year-old (3-yo) commercial blends. The odor relevance of sotolon in the aroma of 3-, 5-, and 10-yo commercial blends (89 MWs) was then appraised by calculating its Odor Activity Value (OAV), after determining its content by RP-HPLC-MS/MS. The sotolon odor perception in MW was as low as 23 µg/L, although it was found that little differences in the wine matrix influenced its perception. OAVs varied between 0.1 and 22, increasing with the blend age. Considering that 16% of the OAVs are higher than 10 (mostly ≥ 10-yo), sotolon was found to be a key contributor to the overall aroma MW blends.

Unveiling the Evolution of Madeira Wine Key Metabolites: A Three-Year Follow-Up Study

“…Previously, an odour detection threshold of 23 µg/L was reported for sotolon in MWs [19]. Considering this, one can observe that sotolon significantly contributes to the aroma of sweet estufagem aged wines, reaching OAVs of up to 17.5.…”

“…In the corresponding wines aged under the canteiro ageing system, its odorant impact was less expressive, and OAVs were lower than 2.9. Moreover, the average OAVs of 3-, 5-, and 10-year-old MWs were found to be 2.8, 6.3, and 9.8, respectively [19]. Thus, the soloton odorant impact in the sweet wines aged by the estufagem process surpassed the average value obtained for 10-year-old MWs while those aged by canteiro were comparable to 3-year-old MWs.…”

“…Sotolon (3-hydroxy-4,5-dimethyl-2(5H)-furanone, also known as caramel furanone, sugar lactone, or fenugreek lactone) imparts a fenugreek, nutty, caramel, curry, rancid, maple syrup, or burnt sugar odour depending on its concentration and enantiomeric distribution [14,15]. It is considered a key aroma of several fortified wines [16,17], including MWs, with concentrations as high as 2000 µg/L [18], well above its odour threshold of 23 µg/L [19]. There is evidence that its occurrence in MW may be related to sugar degradation mechanisms [13,18].…”

An Approach of the Madeira Wine Chemistry

“…Perestrelo et al [80] observed that pantolactone, γ-ethoxybutyrolactone, γ-heptalactone, trans-oak-lactone, and cis-oak-lactone are highest and positively correlated with age for Madeira wines obtained from Malvasia and Boal. In addition, sotolon (3-hydroxy-4,5-dimethyl-2(5H)-furanone) has been considered a key aroma of fortified wines owing to its low OT (few µg/L) and, associated with their characteristic nutty, caramel, and curry odor, depends on its concentration and enantiomeric distribution [95]. According to Câmara et al [89], the concentration of sotolon increases significantly during ageing from 100 (6 year-old) to 1000 µg/L (25-year-old), and for this reason, can be considered a potential ageing marker and a strong contributor to Madeira wine with spicy aromas.…”

Biochemistry of Wine and Beer

“…Additionally, grape-derived wine aroma molecules accumulate in quite different time periods of winemaking; some of them are mostly released during fermentation, while some others accumulate only after long periods of aging. Gaspar et al [13] also studied the odor relevance of sotolon aroma in Madeira wine blends. The results showed that sotolon has an important contribution to the aroma of commercially available Madeira wine blends, particularly in those with long aging periods.…”