Method for extracting garcinia mangostana pericarp pigment by ultrasonic wave method

The invention discloses a method for extracting garcinia mangostana pericarp pigment by an ultrasonic wave method. The method comprises the following steps of: (1) drying garcinia mangostana pericarp at the temperature of 100 and 105 DEG C, and crushing; (2) mixing the product obtained in the step (1) and 95 mass percent ethanol in a mass ratio of feed to liquid of 1:(10-15), and leaching under the conditions of ultrasonic frequency of 40 Hz and heating power of between 800 and 1,000 W for 15 to 30 minutes; (3) filtering the product obtained in the step (2) under vacuum, mixing crude filtrate, and performing suction filtration to obtain a red clarified extracting solution; concentrating the extracting solution under reduced pressure to obtain a pigment colloid; and degreasing by using diethyl ether, and drying to obtain a natural food colorant. The method is simple and low in cost; and the natural pigment extracted by the method is stable in performance, high in coordination with other additives and high in pigmenting property.