Identification of aroma compounds formed during the distillation of Cognac spirits

Abstract : Cognac spirit have a complex composition in aroma compounds which contributes to the product’s typical features perceived by the consumer. These compounds have different origins: they could come from grape musts, can be formed during fermentation, or be produced during distillation. The formation of compounds during distillation remains little understood, making this process hard to control regarding the specific aroma generated by heating during distillation. However, the “Charentaise distillation” of Cognac spirit is a traditional process well described in terms of equipment and operation by professionals. All the aroma compounds found in Cognac spirit freshly distilled results from the combination of several factors occurring before or during distillation. Indeed, the wine’s characteristics (acidity, alcohol content, aroma arising from yeast fermentation…), the method and the period of distillation strongly affect the final aroma composition of freshly distilled spirit. This work focus on the distillation process and in particular on aroma specifically produced by reaction during heating, besides aroma enrichment in final product through volatility principle. The “Charentaise distillation” method to obtain Cognac spirit is performed in two phases: the first step consists in heating the wine introduced in the boiler in order to obtain a distillate called “brouillis”. This brouillis is brought back to the boiler for a second distillation (second step) to obtain the spirit that will undergo a slow maturation in an oak barrel. The double distillation takes place under thermal conditions that could promote the generation of aroma compounds. The aim of this study is to identify these aroma compounds formed during distillation and formulate hypothesis regarding the reactions at the origin of their formation. To study the formation of these compounds at large-scale, a pot-still (alembic) with a capacity of 25 hectoliters have been made available, on which temperature sensors and a density meter have been installed. These devices allow a continuous follow-up on the evolution of these parameters. Sampling during distillation have been performed on the distillate and inside the boiler. The analysis on those samples allowed to perform a mass balance and point out several types of aroma compounds whose quantities have strongly increased during the distillation process. These compounds can be distinguished by their chemical family. Thus, two aldehydes: isobutanal (having a flowery odour) and 2-methylbutanal (having a chocolate odour) are mainly formed during distillation, coming certainly from a Strecker degradation. Moreover, two aromatic compounds, from norisoprenoids family: 1,1,6-trimethyldihydronaphtalene and 1-(2,3,6-trimethylphenyl)-3-buten-2-one commonly called TDN and TMPBE respectively are formed as well. TDN possesses notes of hydrocarbons whereas TMPBE has violet notes. Both are certainly present in the wine in their glycosidic form, and this issue will be studied in detail. The whole results suggest that part of aroma compounds found in Cognac spirit is formed during distillation due to chemical reactivity phenomena to be further studied in depth in our work.
Type de document :
Communication dans un congrès
The Food Factor: Barcelona Conference , Nov 2016, Barcelona, Spain. 2016
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https://hal-agroparistech.archives-ouvertes.fr/hal-01588915
Contributeur : Violaine Athes <>
Soumis le : lundi 18 septembre 2017 - 09:09:14
Dernière modification le : jeudi 13 septembre 2018 - 15:24:11

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  • HAL Id : hal-01588915, version 1

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Pierre Awad, Violaine Athès, Martine Esteban-Decloux, Guillaume Snakkers, Pierre Giampaoli. Identification of aroma compounds formed during the distillation of Cognac spirits. The Food Factor: Barcelona Conference , Nov 2016, Barcelona, Spain. 2016. 〈hal-01588915〉

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