Optimization of ultrasonic-assisted extraction of total flavonoids from seed shell of Juglans mandshurica by response surface methodology

To optimize extraction yield of total flavonoids from seed shell of Juglans mandshurica under ultrasonic assistance, single factor test were carried out at extraction yield of total flavonoids and total reducing power as index.Based on this, power of ultrasonic-assisted extraction, time of ultrasonic-assisted extraction and solid-to-liquid ratio were selected as variables.And a mathematical model was obtained according to response surface methodology.Results showed that the following optimum parameters:power of ultrasonic-assisted extraction, 250W;time of ultrasonic-assisted extraction, 31min;and solid-to-liquid ratio, 1:31 (g/mL) .The predicted value of extraction yield of total flavonoids was 6.70mg/g.After confirmatory test, the relative standard deviation was 1.47%.The regression equation was fitting better with actual situation.