Roses may look red and blueberries blue, but in reality, the color of the berries is quite different. The waxy skin of the fruit is just pretending to be blue.
Fruits like blueberries, black grapes, and certain plums that appear blue are actually covered with a waxy layer. This wax contains tiny nanostructures that scatter blue and ultraviolet light, making the fruit look blue to our eyes. Birds, with the ability to see ultraviolet light, may see these fruits in a different light as well.
Blue is not a common color in nature, and the blue color in fruits is mostly due to the scattering of light rather than pigments. Blueberries, for example, have a high content of anthocyanin which gives them a dark red color under their skin pigment.
Peeling off the outer layer of wax from blueberries reveals that they are not actually blue or red but appear dark. Research shows that the nanostructures on the waxy outer layer create the illusion of the blue hue.
By closely observing the skins of various fruits, researchers discovered the presence of small molecular structures that scatter blue and ultraviolet light.
On February 7th, Middleton’s team shared their findings in scientific progress.
The team was able to replicate the effect in the lab by melting wax from Oregon grapes, then spreading and drying it to mimic the blueberry coating. This could potentially be used to color plastics and cosmetics in a new way.
Have a science question? We can help!
Submit your question here and it might be answered in the next edition of Exploring Science News.
Source: www.snexplores.org
