People are only just realising blueberries aren't blue - and are 'mind blown'

08 February 2024 , 12:42

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Blueberries aren't actually blue (Image: Getty Images)

Every now and again you learn a fact that makes you realise your whole life is a lie.

Blueberries are an incredible superfood. They are rich in antioxidants, potassium and vitamin C - and go just as nicely on top of some yoghurt in the morning as on a stack of pancakes. You might feel like you know everything you need to know about the delicious berry - but it turns out you're wrong.

Did you know that blueberries aren't actually blue? Radio host Rachel Burden shared the revelation on Radio 5 Live Breakfast on February 8.

Early on in the show Rachel teased she would tell listeners "something about blueberries you probably never knew," and would no doubt "raise an eyebrow or two," and co-host Christ Warburton admitted he was "surprised" when he heard it.

Rachel said: "I read this morning that blueberries aren't blue," and Chris replied: "Get out of here. Get out of town." "I know, right? It's a trick of the light."

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Reciting what she'd read the previous day, Rachel explained that analysis had found that the seemingly blue colour came from a "colourless, two micron-thick wax layer," which covers the berry. It is its "intricate microscopic structure" which "interferes with light itself and makes it seem blue to the naked eye".

This was found by scientists at the University of Bristol, who removed the wax, recrystallised it on a piece of paper, and analysed it in a lab. They found that the wax reflected both blue and ultraviolet light, but the human eye can't see the latter, making it appear blue.

Rachel added: "It's thought that the fruit has evolved to look like this, to show off this blue-ish colour, to entice frugivores such as birds. The underlying pigment is more red-ish, but this is a trick also. It's the same sort of trick that hummingbirds have in their feathers, which apparently aren't actually blue either."

Later, she added: "That was a tiny bit of my mind blown this morning." Later in the episode, Rachel said she found the fact "exciting," and Chris said: "I never thought I'd learn this much at 7am on a Thursday morning, that's for sure. That's fantastic."

Rox Middleton, research fellow at Bristol's School of Biological Sciences, said: "The blue of blueberries can't be 'extracted' by squishing – because it isn't located in the pigmented juice that can be squeezed from the fruit. That was why we knew that there must be something strange about the colour."

Ariane Sohrabi-Shiraz