عنوان مقاله [English]
In this study, weld plant dyes were extracted by ultrasonic waves assisted extraction (UAE) method and then, transformed to the concentrated extracts and powder. The efficiency of the extraction process was optimized with employment of a central composite design (CCD), and the optimum conditions of the influential variables, including temperature, time, power of ultrasound, and the bath pH were investigated with response surface methodology (RSM). In this way, an amount of 0.1 g of weld plant powder was extracted in 100 ml of distilled water as the solvent. The optimized amount of variables was found to be of 30 °C, 40 min, 73% of ultrasonic power and pH= 11 of the dyeing bath, where the extraction efficiency was of 87.14%. Then, the extract was analyzed by GC-MS analytical method and 3, 7-dioxo-6, 6, 10-trimethyl-8,10-undecadien-4-yl was identified as the coloring agent of the plant. Also, comparison of using methanol, as the solvent, in conventional extraction method and in UAE method revealed that the use of ultrasound significantly increases the extraction efficiency. Moreover, this technology needs for shorter time in comparison to that of the conventional method.