Purple sweet potato color powder is red to purple red, liquid is brown purple, both has the characteristic odor of sweet potato. It can be dissolved in water & alcohol, propylene glycol solution easily, but not in oil. The color of water solution changes when PH is different. When PH is between2-6, the color is red or purple red .The solution color becomes blue, and is unstable when PH is above 6. The color of solution can’t fade under light for a long time, and also has good resistance to high temperature in an acidic medium.