Optimization by Orthogonal Array Design of Ultrasonic Extraction of Total Flavonoids from Chinese Date Seeds

Objective: The optimal conditions for ultrasonic extraction of total flavonoids from Chinese date seeds were investigated by orthogonal array design.Methods: The content of total flavonoids was determined spectrometrically using rutin as reference substance.The effects of ultrasonic power,extraction time,material/liquid ratio,ethanol concentration on the content of total flavonoids in extracts were investigated by one-factor-at-a-time method,and the extraction conditions were optimized by orthogonal array design.Results: Ethanol concentration and ultrasonic power were the key factors that affect the extraction of total flavonoids.The optimal extraction conditions were obtained as follows: ultrasonic power 450 W,treatment time 30 min,material/liquid ratio 1:50 and ethanol concentration 50%.Under these conditions,the extraction yield of crude total flavonoids from Chinese date seeds was 7.04% and the content of total flavonoids in crude extracts 1.59%.Conclusion: The optimized process remarkably increases the extraction yield of total flavonoids from Chinese date seeds and has a promising prospect for practical applications.