Abstract: The microwave-assisted extraction process of anthocyanins from cranberry was investigated to explore the mechanism of microwave energy absorption and target component transfer in the extraction system. A microwave energy absorption model was established based on the electromagnetic theory to analyze the dielectric properties and the pattern of microwave energy absorption. According to the law of conservation of mass and energy, a heat and mass transfer model was established to analyze the patterns of distribution and variation of temperature and the amount of extracted anthocyanins in the extraction system. The microstructure of cranberry particles was observed by scanning electron microscopy (SEM). The results showed that the dielectric constant, dielectric loss factor and microwave energy absorption were positively correlated with microwave power. The simulation results showed that the higher the microwave power, the higher the temperature at the center of the extraction solvent and the greater the difference in temperature between the bottom and center. The critical temperature for the extraction of anthocyanins was 50 ℃. The concentration of anthocyanins at an extraction temperature lower than 50 ℃ increased with increasing microwave power and extraction time, and the same trend was observed for the degree of degradation of anthocyanins at an extraction temperature higher than 50 ℃. After microwave treatment, the cell wall was broken, and the degree of disruption increased with increasing microwave power. This indicated that microwave could enhance the extraction efficiency of anthocyanins from cranberry. These results can provide a theoretical basis for exploring microwave extraction conditions.

Key words: microwave-assisted extraction; microwave power; cranberry; anthocyanins; model