Tiny external structures in the wax coating of blueberries give them their blue colour, researchers at the University of Bristol can reveal.
Tiny external structures in the wax coating of blueberries give them their blue colour, researchers at the University of Bristol can reveal.
This applies to lots of fruits that are the same colour including damsons, sloes and juniper berries.
In the study, published today in Science Advances, researchers show why blueberries are blue despite the dark red colour of the pigments in the fruit skin. Their blue colour is instead provided by a layer of wax that surrounds the fruit which is made up of miniature structures that scatter blue and UV light. This gives blueberries their blue appearance to humans and blue-UV to birds. The chromatic blue-UV reflectance arises from the interaction of the randomly arranged crystal structures of the epicuticular wax with light.
Rox Middleton, Research Fellow at Bristol’s School of Biological Sciences, explained: “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.
Read more at University of Bristol
Photo Credit: MeszarcsekGergely via Pixabay
