Extraction of monoterpenes from coriander (Coriandrum sativum L.) seeds using subcritical water extraction (SWE) technique

Subcritical water extraction (SWE) of monoterpenes from coriander seeds and effect of extraction conditions were investigated varying temperature (170-200 degrees C) and time (5-20 min). Monoterpenes was influenced by differences in their chemical structures and SWE conditions. The extraction efficiency of linalool was decreased with the increasing extraction temperature and extraction time, whereas linalool oxide was increased due to conversion of linalool to linalool oxide by hydrothermal oxidation. Geraniol, which has the same chemical formula as linalool, was extracted at a high temperature (170 degrees C) owing to the different placement of hydroxyl groups. The efficiency of SWE for geraniol (1.22 +/- 0.22 mg/g) and linalool oxide (0.30 +/- 0.09 mg/g) was higher than that of conventional extraction methods (hexane, methanol, hot water, and hydrodistillation). Therefore, SWE can be used to effectively and selectively extract monoterpenes by exploiting temperature changes in short extraction time.