Review on essential oil extraction from aromatic and medicinal plants: Techniques, performance and economic analysis

Essential oils extracted from herbal plants have many foods, cosmetic and medical industries applications. Present study discussed various conventional extraction techniques (steam distillation, hydro-distillation, hydro diffusion and solvent extraction) and advanced (non-conventional) extraction techniques (solvent free microwave extraction, subcritical extraction liquid and supercritical fluid extraction). Economic analysis, kinetics modelling, and GC-MS analysis of essential oil produced by various extraction techniques have also been presented. India is the biggest producer of Indian basil oil and Japanese peppermint oil, and USA is the major importer and exporter of EOs with 14% (US$390.9 m) of world imports and 17% (US$351.7 m) of world exports. Production cost for Steam distillation, Water distillation, solvent extraction and Supercritical fluid extraction varies from 15.85 - 76.50US$/kg, 7.05-86.4US$/kg, 8.35-8.53US$/kg and 6.71-42.69US$/kg, respectively. Second order model are consistent with experimental data as determination coefficient (R2) is higher than first order model. Non-conventional extraction methods are superior to conventional extraction methods in terms of low cost, time and energy saving, less solvent requirements, shorter extraction time, etc. From the techno-economic and environmental perspective, water distillation with full energy integration is the best method for rosemary oil. In contrast, supercritical fluid extraction is the best method for oregano oil.