Model ageing effects on the formation and evolution of minty terpenoids in red wine

Abstract

AIM: A pool of terpenoids possibly implicated in minty odours and in the appreciable refreshing sensation, has been identified in the ageing bouquet of red Bordeaux wines (Picard et al., 2016; Picard et al., 2017; Picard et al., 2018). Recent results on Corvina and Corvinone wines, revealed that these compounds already exist in young wines, but at lower concentrations than in aged ones (Lisanti et al., 2019), thus suggesting their formation during ageing. The mechanisms of this formation are still unclear. In some vegetal species, as mint, these terpenoids arise from an enzymatic limonene biotransformation pathway (Mahmoud & Croteau,2003), however their chemical origin from limonene or other precursors may not be excluded. In the present study, an experiment of model ageing of young wines was conducted in order to give a contribution to the comprehension of the origin of minty terpenoids in aged wines.

METHODS: Two 1-year-old wines of the Bordeaux area, Merlot and Cabernet franc, were warmed under controlled conditions, in order to mimic a part of ageing. Limonene, 1,8-cineole, menthone, pulegone, carvone, piperitone, mintlactone, menthyl acetate and neomenthyl acetate were determined at the beginning and after 2, 3, 7 and 11 days of accelerate ageing. The quantification of the minty terpenoids was performed by a new method that couples Headspace-SPME Arrow extraction with GC/MS-MS analysis.

RESULTS: A progressive decrease of limonene concentration (up to 76%) and an increase of the levels of piperitone (up to 200%) and mintlactone (up to 277%) were observed in both wines during the “accelerate ageing”. For the other compounds (1,8-cineole, menthone, pulegone, carvone) an initial increase, followed by a decrease was observed. 

CONCLUSIONS

Our results suggest that a chemical conversion of limonene into its derivatives may occur. Now the mechanisms must be elucidated to better understand the possible implication of these compounds in the complexity of aged wines bouquet.