Ultrasonic Treatment Followed by Microwave Treatment for Extraction of Flavonoids from Orange Peel

In order to improve the extraction yield of total flavonoids from orange peel,sequential treatments with ultrasonic followed by microwave were used for the extraction of total flavonoids. The effects of concentration of ethanol as the extraction solvent,solid/liquid ratio and microwave power and treatment time on the extraction yield of total flavonoids were explored by single-factor and orthogonal array design methods. The combination of ultrasonic with microwave gave higher extraction efficiency than the use of ultrasonic and microwave alone,and a maximum extraction yield of total flavonoids was achieved after soaking in 20-fold volume of 70% ethanol for 30 min,followed by ultrasonic treatment for 30 min and subsequent 400 W microwave treatment for 3 min.