Pilot-scale extraction and fractional separation of onion oleoresin using supercritical carbon dioxide Original Research Article

Supercritical carbon dioxide extraction of onion flavour was studied using a high pressure apparatus with a 5 l extractor vessel volume. Designed experiments were carried out to map quantitative effects of extraction pressure and temperature on the extraction yield and sulphur recovery. Stagewise precipitations of the extracts were carried out using two separators in series in order to obtain essential oil rich products with a high-sulphur content. The extraction with carbon dioxide was compared to conventional steam distillation and Soxhlet extraction with hexane and ethyl alcohol.