Abstract:

In order to obtain optimum conditions for extracting flavonoids from blueberry leaves under the assistance of ultrasonic, on the basis of single factor investigations, Box-Behnken experimental design was used to provide experimental data for establishing a regression model describing the extraction of flavonoids, and response surface and contour diagrams with the extraction yield of flavonoids as response were plotted for analyzing the pairwise interactive effects of ethanol concentration, material-to-liquid ratio, extraction temperature, microwave power and extraction duration on the response. The analysis of variances revealed that ethanol concentration, extraction temperature and microwave power had significant effect on the extraction yield of flavonoids. Extraction temperature of 72 ℃, ethanol concentration of 64% and microwave power of 456 W were found optimum. Under the optimized conditions, the maximum extraction yield of flavonoids was 4.232%.

Key words: blueberry leaves, extraction process, flavonoids, optimization of process parameters, response surface methodology