Researchers at the University of Cambridge have discovered a way to capture the intense, no-fade colour in a particular plant that could be replace pigments used in industry with natural plant extracts in products.
The Pollia condensata plant (sometimes called the marble berry)- a species that grows wild the forests of Ethiopia, Mozambique, Tanzania and other African countries– produces a berry that is iridescent blue and metallic, a colour that Wired Magazine “the most intense colour in the biological world [that] literally outshines any other plant or animal substance in the world.”
“[The plant’s berries are] 10 times more intense and bright than any colour achieved with a pigment,” said Dr. Silvia Vignolini, a physicist at the University of Cambridge who led the study with plant scientist Beverley Glover. The marble berry has been found by scientists to be the “brightest biological substance” in nature.
The biological foundation of most green plants, cellulose is very common in nature; thus, inexpensive to obtain and process. Its astonishing brightness, low cost, and non-toxicity could make it an effective replacement for conventional pigments.
The cells of this African fruit have walls made of tightly coiled cellulose strands that are excellent for reflecting light. Unlike pigments, structural biological colours do not fade over time because they are not broken down by absorbing light. Structural colours have an immense staying power, some remaining vivid in the fossils of beetles that lived 50 million years ago.
A colour similar to the Pollia condensate berries exist in the wings of the morpho butterfly but these berries, according to physicist Ullrich Steiner, produce an even stronger colour. Samples of the fruit in plant collections dating back to the 19th century have not lost any shine or intensity.
Silvia Vignolini and Beverley Glover have determined that the powerful, non-fading “structural color” of Pollia condensata could have widespread applications in a variety of industries. Food dyes, makeup, car paint, colored security features in currency, and many other products could be enhanced by this discovery. Silvia Vignolini stated: “edible, cellulose-based nanostructures with structural color can be used as substitutes for toxic dyes and colorants in food”. Dr. Vignolini also stated that “the paper industry is already set up to extract and use cellulose and its processes could also be adapted for security labeling or cosmetics. Cellulose-based structures have a really strong optical response and are completely inert in the human body”.