Isolation of coriander (Coriandrum sativum L.) essential oil by green extractions versus traditional techniques

Traditional techniques for coriander (Coriandrum sativum L.) essential oil (EO) isolation (hydrodistillation and solid-liquid extraction with methylene chloride) were compared with green and environmentally safe processes such as supercritical fluid extraction (SFE) and subcritical water extraction (SWE). SFE was performed on different pressures (100 and 300 bar), while all other parameters were constant. In case of SWE, different temperatures were used (100, 150 and 200 degrees C), while other extraction conditions were the same. EO and lipid extracts were compared in terms of total extraction yield and qualitative and quantitative composition. Highest extraction yields were obtained by Soxhlet extraction and SFE on 300 bar and 40 degrees C (14.45% and 8.88%, respectively), while SWE on 100 degrees C provided lowest yield of lipid extract (0.36%). Concerning yields of five dominant compounds from coriander EO (gamma-terpinene, (+)-limonene, linalool, camphor and geraniol), highest yields of oxygenated monoterpenes (linalool, camphor and geraniol) were obtained by Soxhlet extraction (785.05, 26.73 and 21.96 mg/100 g of coriander seeds (CS), respectively), while gamma-terpinene and (+)-limonene extraction yields (31.08 and 23.98 mg/100 g CS, respectively) were highest by SFE on 300 bar and 40 degrees C SFE on these conditions also provided particularly high yields of linalool, camphor and geraniol (598.51, 26.64 and 19.54 mg/100 g CS, respectively). Besides EO, SFE provided extraction of vegetal oil while, polyphenolics were also extracted by SWE, increasing health value of obtained extracts, and presenting good alternatives for traditional techniques for EO extraction, i.e. isolation. (C) 2015 Elsevier B.V. All rights reserved.