Bitter orange distillation: determination of key odourants then simulation of distillation
Résumé
Citrus peeling distillation is known to lead to high quality fragrances. However, the compounds responsible for the odour of the bitter orange (Citrus aurantium L.) distillate are poorly known. Moreover, the technological parameters that could affect the composition of the distillate are not well understood. The aim of this study was to focus on key odour compounds of the bitter orange peel throughout the process in order to get a good understanding of the interest of each step and envisage optimisation. The following strategy was applied: (i) identification of key odour markers in the essential oil and the heart cut distillate; (ii) precise study of the process steps from the raw materials to the heart cut distillate; (iii) study of the impact of distillation parameters on key markers, (iv) modelling of distillation with BatchColumn software. (i) Among the 51 and 40 volatile compounds identified by gas-chromatography coupled with mass spectrometry, we found 19 odour-impact molecules in the essential oil and 7 in the heart cut distillate using GC-Olfactometry. (ii) We demonstrated that distillation has a big impact on the quality of the heart cut (distillate). (iii) Measuring of the behaviour of the key markers during the distillation linked with their physico-chemical characteristics gave us a better understand of this step. (iv) Assessment of the vapourliquid equilibrium data of some key compounds and the corresponding thermodynamic model allowed simulating the distillation step with BatchColumn software from ProSim®. The good knowledge of these steps allows testing new strategies for product innovation .