Simulation And Analysis On The Process Of Anthocyanins From Blueberry By Microwave-assisted Extraction

Extraction and degradation simulutanously occur in microwave extracting target components in plant-material. Investigation of this synchronous process conduces to the analysis of microwave extraction mechanism and improvement of extraction yield of target components. Buleberry powder was selected as objective material and anthocyanin was selected as target components. Extraction and degradation mechanism of anthocyanin was revealed by process analysis and kinetic model development of microwave extracting anthocyanin from blueberry powder. Pressure contribution induced by microwave volumetric heating inside extraction system was analyzed to the anthocyanin extraction. The research results present the theorical basis for the reasonable microwave extraction technology with high yield and low degradation of target components.The influence of extraction temperature and extraction time on the target factors was analyzed by the factorial test methods. A central composite experiment of four factors and five levels was designed, and the quadratic regression models were built between response values and experimental factors. For the anthocyanin degradation yield in studied rang, ethanol concentration has the most significant influence, followed by the solid-liquid ratio and extraction temperature, extraction time is the least. The optimal parameters of microwave extraction anthocyanins from blueberry was obtained in the ethanol concentration of 65%, extraction time of 6 min, extraction temperature of 51 ℃ and solid-liquid ratio of 1:29. The extraction yield of anthocyanin was up to 82.09%, and the degradation yield was as low as 8.13%. Microwave extraction technology may improve the extraction yield of target component and efficiency.In order to explore the kinetics mechanism of microwave-assisted extraction technology, the theorical model of extraction kinetics for microwave-assisted extraction process was built based on the diffusion theory of solid-liquid mass transfer and Fick’s law. The process parameters, such as the mass of extracted solute, extraction yield and extraction speed were derived. The model showed that the concentration of solute in solution increased with the increase of extraction temperature, solid-liquid ratio and material particles radius. A coalescence extraction model of semi-theoretical and semi-empirical was built by pluging the experimental data into theorical model, which could synchronized characterize the role of extraction and degradation of anthocyanin during the process of microwave extraction. Multivariate nonlinear regression was used to fit the coefficients of extraction kinetics model and factors.In order to present a novel method for pressure caused by microwave during the extraction process, the process conditions for the test of microwave-induced pressure field forming were studied. The extraction power, heating time and extraction temperature were selected as the experimental factors. The anthocyanin extraction yield, degradation yield and the internal pressure of the extraction system were selected as the objective factors. The central composite experiment method with three factors and five levels was employed to build the quadratic regression models between response values and each experimental factor. For the anthocyanin degradation yield in studied rang, extraction power has the most significant influence, followed by the extraction temperature and heating time. For the internal pressure of the extraction system, extraction power is the best influence to the yield, followed by the extraction temperature and heating time. The optimal parameters for the test of microwave-induced pressure field forming was obtained.The extraction power was 1056 W, heating time was 76 s and extraction temperature was 52 ℃. The extraction yield of anthocyanin was up to 82.27%, and the degradation yield was as low as 7.81%, under internal pressure of 0.04 bar in the extraction system. The transfer and extraction process of target compound under the new microwave extraction mode can be controlled.