Materials and Methods
2.1 Plant material
The fresh Butterfly Pea Flowers (Clitoria ternatea) were bought from Chiang Mai main market (Chiang Mai, Thailand). The flowers were fleshly harvested from the northern area of Chiang Mai province of Thailand in September 2013. The individual flower, without defects and diseases, were selected and de-stemmed. All samples were stored at 4°C standard refrigerator prior to further experiment, which were not more than 3 days after harvested.