Effect of power ultrasound on the extraction of black caraway ( L.) and evaluation of their qualitative properties using response surface methodology.

In this research, ultrasound-assisted extraction (UAE) with two types of continuous and pulsed sonication extraction was compared with the Soxhlet method in the evaluation of qualitative traits of caraway seeds as a medicinal plant. Treatment conditions were performed at three levels of treatment (continuous and on-off levels), ultrasound power (100, 200, and 300 W), and sonication duration (10, 15, and 20min) using the response surface methodology (RSM) to compare them. Results indicated that yield of the dry extract weight and amount of ascorbic acid increased by the intensity and sonication duration directly but about DPPH radical scavenging capacity there is no direct relation, actually comparing DPPH radical scavenging capacity yields showed that it increased initially from 100W to 200 W, then from 200 to 300W, the result was reversed. It is due to the occurrence of power peaks during extraction , degradation of more and better plant matrices, and better released of the extract in low powers. Results also showed that pulsed sonication method was more effective than continuous to extraction of sensitive components.