Oh Raphanus sativus, why are you red?

In the past couple years I have picked up a radish habit.  I get some fresh radishes, wash, scrub and dry them and eat them with butter and salt.  In the process of preparing the radishes I wonder about their bright red color, and the fact that when immersed in water, a purple color results in the water.

What actually caused the red in a radish?  Here's the answer:

There are some very interesting pigments in radishes.  The pigments are called anthocyanins and there are four main types in red radishes.

Two novel diacylated anthocyanins, 
1) pelargonidin 3-O-[2-O-(β-glucopyranosyl)-6-O-(trans-p-coumaroyl)-β-glucopyranoside] 5-O-(6-O-malonyl-β-glucopyranoside) and 
2) pelargonidin 3-O-[2-O-(β-glucopyranosyl)-6-O-(trans-feruloyl)-β-glucopyranoside] 5-O-(6-O-malonyl-β-glucopyranoside), were characterized. 


Two other monoacylated anthocyanins were determined to be 


3) pelargonidin 3-O-[2-O-(β-glucopyranosyl)-6-O-(trans-p-coumaroyl)-β-d-glucopyranoside] 5-O-(β-glucopyranoside) and 


4)  pelargonidin 3-O-[2-O-(β-glucopyranosyl)-6-O-(trans-feruloyl)-β-glucopyranoside] 5-O-(β-glucopyranoside). 


I think we may need a few organic and biochemistry reviews in order to appreciate what we have here.  The link to a useful paper is here:


http://pubs.acs.org/doi/abs/10.1021/jf980695b

But, I am assuming most of you won't have access to the full text, so let's take a different tack.  The name of the compound, pelaronidin is very interesting. Let's find out more:

https://wiki.ch.ic.ac.uk/wiki/index.php?title=It:Pelargonidin

Aha, it is a flavonoid, and these compounds enrich our lives by providing many of the beautiful, bright colors we see in the natural world.  It seems our pelargonidin provides the colors in strawberries, red geraniums and raspberries.

Fascinating!