Blue pea, Butterfly pea or ‘Dok Anchan’ in Thai is a plant widespread in southeast Asia. The flowers of the blue pea are used as a natural food colorant dyeing food in beautiful blue.
To foreign eyes, some of the colors used for dyeing food and especially desserts may seem odd, especially when an assumption of artificially coloring the food is made. Knowing that Thais actually use natural ingredients to dye food, showcases once again the wisdom of this cuisine and its roots in the natural surroundings.
The blue pea is used to dye drinks, rice, custards and more. When lime is squeezed into the blue liquid the chemical reaction changes the color to a beautiful purple.
Nam Dok Anchan 
Blue sticky rice ready to be paired with mango
Thaifooding 