SUBCRITICAL WATER EXTRACTION OF ESSENTIAL OILS FROM <i>ZATARIA MULTIFLORA</i> BOISS

Abstract

ABSTRACT The essential oil of Zataria multiflora Boiss., cultivated in Iran, was extracted by subcritical water extraction (SCWE) and compared with two conventional methods, including hydrodistillation and Soxhlet extraction. The extraction efficiencies of different temperatures (100, 125, 150 and 175C), mean particle sizes (0.25, 0.50 and 1 mm) and water flow rates (1, 2 and 4 mL/min) were investigated at 20 bar. The separation and identification of the components were carried out by gas chromatrography (GC)‐flame ionization detection and GC‐mass spectrometry. The best operating conditions for the SCWE of Z. multiflora Boiss. were determined to be at 150C temperature, 0.50‐mm mean particle size and 2 mL/min flow rate for 150 min extraction time. The SCWE method resulted in a more valuable essential oil with respect to the oxygenated components. PRACTICAL APPLICATIONS Subcritical water can be used in many different fields of applications. In recent years, the extraction of flavors, fragrances and antioxidant components from plant materials, and the hydrolysis of carbohydrates, vegetable oils and fatty acids have been widely investigated by many researchers. Using subcritical water for analytical purposes and for soil remediation, and applying it as a reaction media are some other interesting fields for practical applications.