抽象的

Experimental and modeling studies on microwave assisted extraction of xanthones from roots of Securidaca longepedunculata

Gertrude Eléonore Djiobie Tchienou

 Microwave-Assisted Extraction (MAE) has been developed to extract xanthones from roots of Securidaca longepedunculata Fresen. The influence of several independent variables such as extraction (irradiation) time, microwave power and liquid to solid ratio has been studied under varying conditions using one-factor-at-a-time analysis to obtain an optimal extraction. The xanthones concentration– time data were analysed using a second order kinetic model to determine extraction constant. A diffusion model was utilized to determine diffusion coefficient taking into account of both washing and diffusion phases together. Solvent-to-liquid ratio and microwave power experimental data at different conditions were fitted with a Gaussian model. The maximum xanthones content of 2550 μgEDMX/gP is obtained at extraction time of 83s, microwave power of 624 W and liquid solid ratio 0,93g/20 mL. The experimental profiles are fitted into a two-parameter modified first-order kinetic model and a three-parameter modified exponential model and checked using the goodness-of-fit criterion. The kinetic and gaussian models proved that the extraction process was based on the second-order extraction model as the experimentally done. The second-order model was satisfactorily applied, with very high coefficients of correlation (R2 = 0.9861), showing that it perfectly described the process.