Blueberries appear blue despite the dark red pigment of their skin because in the very thin layer of natural wax that covers them there are crystalline microstructures that reflect blue light, visible to the human eye, and ultraviolet rays, visible to birds.
This was discovered by British researchers at the University of Bristol, thanks to a study that paves the way for the development of new sustainable, biocompatible and even edible dyes.
The results are published in the journal Science Advances.
“It was really interesting to discover that there was an unknown coloring mechanism right before our eyes, on popular fruits that we grow and eat all the time,” says researcher Rox Middleton. “The blue in blueberries cannot be 'extracted' by juicing , because it is not found in the pigmented juice that can be obtained from the fruit. That's why we knew there had to be something strange about the color. So we removed the wax and recrystallized it onto the card and by doing so we were able to create a brand new coating that reflects blue and UV light".
The ultra-thin dye is approximately two thousandths of a millimeter thick, appears blue and reflects UV rays well, paving the way for new coloring methods.
Reproduction reserved © Copyright ANSA