Extraction of Caraway essential oils by ultrasonic-assisted salting-out hydrodistillation

To obtain the Caraway (Carum carvi L.) essential oils by the ultrasonic-assisted salting-out (UASHDE) hydrodistillation extraction, the optimum extraction conditions were investigated. Six factors were studied in present paper, and they were material to solvent ratio, sodium chloride concentration, soaking time, ultrasonic frequency, ultrasonic power, and ultrasonic time. The results showed that the optimal conditions were as follows:material to solvent ratio 1:15, sodium chloride concentration 15%, soaking time 60min, ultrasonic frequency 25kHz, ultrasonic power 250W, and ultrasonic time 30min. The average rate of essential oils on the optimal condition was 5. 42%±0. 01%, which was increased by 1. 24% compared with that of salting-out hydrodistillation extraction (SHDE) . By the application of gas chromatography-mass spectrometry (GC-MS) techniques, constituents of caraway essential oil extracted were identified, and isolated 27 kinds of chemical composition, of which, limonene (31. 08%) and D (+) -carvone (66. 42%) were the major constituents. However, the chemical composition (15) and principal component content (limonene 21. 84% and D (+) -carvone 76. 29%) of Caraway essential oils obtained by SHDE were significantly different with that obtained by UASHDE. The results showed that UASHDE was superior to SHDE with respect to extraction time, essential oil yield and quality.