The Alphabet of Coloured Food!

Recently I went to a local market that was full of all kinds of winter produce. And the one thing that kept catching my eye was a variety of purple veg! Purple leaves of amaranth, purple yams, purple eggplants, purple rat-tail radish... So bright and vivid, they got me thinking about what exactly gives our fruit and vegetables their colours.

Veggie VYBGYOR

Food colours are certain wavelengths of light that we see when we look at certain foods, depending on what wavelengths the food absorbs and reflects. This colour of the food is created by the pigment that naturally occurs in the food.

The more I thought and read about it, the more I realised that a majority of the natural foods we eat owe their colour to just a handful of compounds - the ABCs of plant pigments:

A is for Anthocyanins

This pigment is responsible for the brilliant hues of Raspberries, Blood Oranges, Red Cabbage, Purple Corn, Eggplants, Blueberries, and Blackcurrants, among others.

Mulberries contain Anthocyanins

Depending on the pH of the food, anthocyanins make food look red, purple, blue, even black!

Many of the purple foods I saw at the Grant Road bhaji galli (and then obsessively posted about on my Instagram) were also pigmented by anthocyanins!

B is for Betalains

A class of yellow and red pigments, Betalains are found in many flowering plants. They're most often seen in the petals of the flowers but also appear in the fruits, leaves, stems and roots: think beetroot micro-greens with their magenta stems, and amaranth leaves in a brilliant burgundy.

Beetroot Microgreens

Red Amaranth leaves

The deep purplish red of those plants comes from one category of bealains called Betacyanins. These hues are similar to those produced by anthocyanins, so it's easy to get confused about which of the two is giving a certain red or purple food it's colour. The key to understanding that requires a breakdown of botanical classifications, which I won't get into here and now.

Those Swiss Chard stems! (source: wikipedia)

The second category of Betalians, called Betaxanthins, produce more yellow and orange hues, like the ones seen in swiss chard.

C is for Carotenoids

The pigment that colours Carrots (of course!), Carotenoids create a range of yellow and red hues. Other vegetables that owe their colour to these pigments are corn, oranges, tomatoes, pink grapefruit, red palm oil... Even chilies with their vibrant reds have Carotenoids to thanks!

Red chilies have carotenoids

So does this red palm oil from Burundi

What I find most interesting about carotenoids is that unlike Anthocyanins and Betalains, which are water-soluable pigments, carotenoids are fat soluble. This allows animal cells to store carotenoids consumed from plant sources within it's fat molecules!  

One example of this, which you probably see first-hand if you live in an Indian household, is the colour of ghee. The yellowness of the ghee is dependant on how much grass is in the cow's diet, as opposed to grain. If you eat beef you might also observe this in the colour of the fat on the meat.

Similarly, the colour of egg yolks is dependant on the diet of the chickens that lay the eggs (and not the quality of the egg itself, contrary to popular belief). So when chickens are fed carotenoid-rich red chili peppers, the yolks of their eggs begin to turn a from a sunny yellow to a brilliant red!

Crustaceans have carotenoids too (pink prawns and red-shelled crabs!). Flamingoes feast on these crustaceans, and then they digest the carotenoids, which get dissolved in their fat and deposited in the new feathers they grow. And that is how flamingoes get their incredible orangish-pink plumage!

Flamingos are pink because of the carotenoids they eat

Finally, C is also for that product of photosynthesis we've all learned about as kids.

Yup, Chlorophyll!

So if you think about it, the natural world has managed to create a whole rainbow of fruits and vegetables using a combination of these ABCs of plant pigments. Fascinating isn't it?