Optimization of Subcritical Water Extraction of Pimpinella anisum Seeds

Abstract

:Many improved methods including subcritical water extraction (SWE) are being used in extraction technologies of food compositions to minimize use of organic solvents. It is faster, cleaner and cheaper compared to other conventional extraction methods that are in practice during these days. Subcritical water extraction (SWE) based on the use of water as an extractant, at temperatures between 100 and 374oC and pressures high enough to maintain the liquid state was applied for extraction of essential oil from Pimpinella anisum seeds. Trans-anethole as the main component of the extracted essential oils was quantified by reversed phase-high performance liquid chromatography with UV detection at 266 nm. Initially, extraction results of t-anethole was screened by Plackett-Burman design to determine the most important variables. The results showed that the water flow rate, temperature and mean particle size affected the essential oil extraction significantly (p<0.05), but the pressure and length-to-diameter ratio of extraction cell had insignificant effects. The response surface methodology (RSM), based on Box-Behnken Design was employed to optimize the significant parameters. The temperature of 170oC, water flow rate of 2.8 mL/min and mean particle size 0.6 mm were determined as optimum for operating SWE. The SWE efficiency at optimized conditions was significant compared by Soxhlet extraction.