engleski

Microwave and ultrasound assisted extractions of polyphenols from dandelion (Taraxacum officinale) root and leaf

Microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) as ecofriendly procedures are widely employed in the analysis and the extraction of bioactive compounds from plants. In comparison to the conventional solvent extraction method, MAE is more advanced as it heats the matrix internally and externally without a thermal gradient thus target compounds can be extracted more effectively and protectively using less energy and solvent. Moreover, the main advantages of using UAE includes more effective mixing of matrix and solvent, faster mass transfer, reduced thermal and concentration gradients, and less energy and solvent consumption. Hence, the aim of this study was to investigate UAE and MAE for isolation of total phenols from dandelion (Taraxacum officinale (L.) Weber ex F.H. Wigg) roots and leaves. Several parameters such as ethanol concentrations (50 vs. 70%, v/v), and time (5, 10, 15 min) were studied for both techniques. Moreover, MAE was conducted at various temperature (40, 60, 80°C) while sonication was performed at 20 kHz, at 50% and I 00% amplitude of the full power ( 600 W) in the ambient atmosphere. MAE has given the highest yields for root at 60°C, 15 min, 70% aqueous ethanol (v/v), and for dandelion leaf at 40°C, IO min and 50% aqueous solution of ethanol (v/v). In addition, high amplitude (100%) and high presence of ethanol in the solvent (70%) under 10 min improved significantly the UAE process of polyphenols recovery from roots, while UAE process with 50% aqueous ethanol (v/v), 50% amplitude in 15 min was found as the optimal for polyphenols recovery from the dandelion leaf. In conclusion, both techniques confirmed suitability for polyphenols recovery from dandelion roots and leaves.

microwave-assisted extraction (MAE) ; ultrasound-assisted extraction (UAE) ; dandelion (TARAXACUM OFFICINALE) ; polyphenols

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