Monday, August 30, 2010

Remember Hypercolour?

Those shirts? I'm not sure how big these actually were as a trend, but I can say they were height of fifth grade fashion in 1988. (Everyone who was anyone was sporting a splotchy hand print.)

So imagine my surprise when the beautiful purple beans I'd bought at the farmers' market started to turn green in a very hypercolouresque way (left) once they began to simmer.

In both cases — shirt and beans — colour change is the result of a chemical process. (Ah, the eighties — when it wasn't at all weird to wear chemically reactive clothing to make a statement.)

With the beans:

"What happened was the heat from the cooking broke apart the molecules on the surface of the bean [i.e., pigments called anthocyanins] and exposed the chlorophyll which is green." (Source: MadSci Network)

Anthocyanins also give purple carrots and potatoes their pigment. But unlike the beans, they retain their colour though the cooking process (right). I'm guessing that's because, as root vegetables, they lack the chlorophyll of vegetables that grow above ground.   

Is that right, Mr. Wizard?

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