Metabolomics as a tool for the authentication of rose extracts used in flavour and fragrance area
Résumé
Natural extracts used in flavour and fragrances are exposed to authentication issues. Companies working in this industrial market acquire the raw materials locally but also abroad, sourcing exotic plants with specific olfactive features or lower costs of production. The geographical origin, the botanical variety, environmental conditions, extraction processes and storage conditions represent some parameters affecting the natural extract quality. All these factors are likely to affect the sensorial properties and especially the organoleptic characteristics of the extract. In addition, fraudulent practices known as adulterations have also an impact on the quality. Sensitive and precise analytical techniques are required to identify adulterations among other sources of variability. In this context, the highly valuable rose absolute was selected as a model study for its importance in perfumery. The existence of two botanical species and several production countries are additional reasons that make this extract an interesting case study. Because the usual GC-MS metabolomic approach is not able to cover the broad range of nonvolatile compounds, complementary approaches are required. An UHPLC-ToFMS fingerprinting approach was therefore developed to allow the identification of nonvolatile markers of the two closely related species of the genus Rosa. Thus, 12-oxophytodienoic acid was identified as a biomarker (level 2 according to MSI guideline) enabling the distinction between R. centifolia and R. damascena. Our results finally underline the efficiency of the UHPLC-ToFMS metabolomic approach for the qualification of odorant extracts.