Butterfly pea (Clitoria ternatea), a twining vine native to Southeast Asia, produces deep blue to purple flowers that bloom nearly year-round in ideal conditions. When extracted in a liquid, the addition of a mild acid such as lemon or lime juice turns the naturally deep blue to purple color into a much lighter pink or purple color, giving the extract its color-changing ability. This new 5-page publication of the UF/IFAS Environmental Horticulture Department outlines the use of butterfly pea flower extract (BPFE) as a pH-dependent natural colorant, including an explanation of the science behind the color change, detailed parameters for flower extraction, instructions for storage and processing of the extract as well as a discussion of some of the other benefits of using BPFE. Written by Sean Michael Campbell and Brian Pearson.
http://edis.ifas.ufl.edu/ep573