Extraction and purification of red pigment from pericarp of purple potato

A red pigment was extracted from pericarp of purple potato by ultrasonic technology.The extraction conditions were studied using orthogonal test.The optimum extraction condition were as followed: the extraction solvent 1% HCl,the ultrasonic power 400W,the ultrasonic temperature 45℃,the ultrasonic time 20min and the material-liquid ratio 1∶10.Under these conditions,the red pigment extraction rate was 3.94%,which was enhanced by 34.93% compared to that of traditional solvent extraction.The red pigment was absorbed on the HPD-400 resin,and desorbed by 70% alcohol.The red pigment with high quality was obtained after vacuum distillation.Its color value was 25.23,which was 1.77 fold of value without purification.