1. Introduction
Clitoria ternatea, called Butterfly Pea, is tendrils grown in Thailand. There are many common names including un-chan, uang-chan and dang-chan. Characteristics of the butterfly pea are a perennial herbaceous plant with elliptic and obtuse leaves. It grows as a vine in moist and neutral soil. The important feature about this plant is its vivid deep blue flowers; solitary with light yellow markings (Singh and Tiwari, 2012). In Thailand, butterfly pea flower is widely used as a natural food coloring.