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

Supercritical carbon dioxide extraction of onion flavour was studied using a high pressure apparatus with a 5 1 extractor vessel volume. Designed expe riments were carried out to map quantitative effects of extraction pressure and temperature on the extraction yield and sulphur recovery. Stagewise pr ecipitations of the extracts were carried out using two separators in serie s in order to obtain essential oil rich products with a high-sulphur conten t. The extraction with carbon dioxide was compared to conventional steam di stillation and Soxhlet extraction with hexane and ethyl alcohol. (C) 2000 E lsevier Science Ltd. All rights reserved.