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John Carlos Baez

Ain't it pretty? People extract curcumin from turmeric to use as a food coloring in curry powders, mustards, butters, cheeses, and prepared foods. It's also used in dietary supplements due to its unproven and dubious health benefits.

It doesn't dissolve well in water, but it does in alcohol. If you dissolve some curcurmin in vodka and shine a black light on it, you'll see it's fluorescent! That is: it absorbs the high-energy ultraviolet photons and emits lower-energy green photons... the same kind of light it usually likes to *absorb.* Due to the principle of reciprocity, if a substance is good at absorbing some frequency of light, it's also good at emitting that frequency.

Let's see that fluorescence! Check out my next post.

(2/n)

5 comments
John Carlos Baez

Here's curcumin dissolved in a hydrocarbon called xylene with ultraviolet light shining on it! It's fluorescent. You can also dissolve it in ethanol, e.g. vodka.

Curcurmin also makes a good pH detector: if you mix it with a base it turns red. This video by @compoundchem illustrates it:

youtube.com/watch?v=PsVtME5o69

(3/n, n = 3)

Matteo Capucci

@johncarlosbaez @compoundchem this explains many culinary experiences I had, amazing

John Carlos Baez

@mc - I've spent a lot of time trying to wash turmeric out of my clothes; I should have been using vodka.

Jos Dingjan

@johncarlosbaez In Dutch turmeric is called either “kurkuma” (after the Sanskrit name, I guess the source of both the name of the genus and of “curcumin”), “geelwortel” (= yellowroot), or kunyit/koenjit (from Indonesian)

John Carlos Baez

@happydisciple - nice! I was wondering where that word 'curcumin' came from, and I was confused by 'cucurbits'.

en.wikipedia.org/wiki/Cucurbit

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