Proposed Models for Subcritical Water Extraction of Essential Oils

作     者：M.Khajenoori A.Haghighi Asl F.Hormozi 

作者机构：Chemical Engineering DepartmentFaculty of EngineeringSemnan University 

出 版 物：《Chinese Journal of Chemical Engineering》 (中国化学工程学报（英文版）)

年 卷 期：2009年第17卷第3期

页      面：359-365页

核心收录：

学科分类：0710[理学-生物学] 0832[工学-食品科学与工程（可授工学、农学学位）] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 0817[工学-化学工程与技术] 08[工学] 0703[理学-化学] 083202[工学-粮食、油脂及植物蛋白工程] 

基　　金：support is gratefully acknowledged to the Semnan University and the Iranian Research Organization for Science and Technology (IROST) 

主　　题：essential oils Zataria multiflora Boiss. subcrltlcal water extraction mechanisn 

摘      要：Mechanisms that control the extraction rate of essential oil from Zataria multiflora Boiss. (Z. multiflora) with subcritical water (SW) were studied. The extraction curves at different solvent flow rates were used to deter-mine whether the extractions were limited primarily by the near equilibrium partitioning of the analyte between the matrix and solvent (i.e. partitioning thermodynamics) or by the rates of analyte desorption from the matrix (i.e. ki-netics). Four simple models have been applied to describe the extraction profiles obtained with SW: (1) a model based solely on the thermodynamic distribution coefficient KD, which assumes that analyte desorption from the ma-trix is rapid compared to elution; (2) one-site kinetic model, which assumes that the extraction rate is limited by the analyte desorption rate from the matrix, and is not limited by the thermodynamic (KD) partitioning that occurs dur-ing elution; (3) two-site kinetic model and (4) external mass transfer resistance model. For SW extraction, the thermodynamic elution of analytes from the matrix was the prevailing mechanism as evidenced by the fact that ex-traction rates increased proportionally with the SW flow rate. This was also confirmed by the fact that simple re-moval calculations based on determined KD (for major essential oil compounds) gave good fits to experimental data for flow rates from 1 to 4 ml·min-1. The results suggested that the overall extraction mechanism was influenced by solute partitioning equilibrium with external mass transfer through liquid film.