The colorants  that give purple sweet potato color their characteristic color are anthocyanins. These colorants exhibit a 

reversible change in molecular structure as the PH of solutions change from acide to basic.

This change in structure is characterized by a shift in hue from red to purple red as the PH changes from acide to basic.

Application: 

Flavors,energy drinks,soy drinks,spirits,juice drinks,specialty tea,ice cream,yogurt smoothies,fruit preparation,salad dressing,breakfast cereal,dry mixes.

Package: 

Liquid: polyethylene barrel; 25kg per barrel;

Powder: inner package polyethylene bag; outer package carton,10kg per carton,15kg per carton,20kg per carton