Beets bleed red but a chemistry tweak can create a blue hue
Beet juice is red. Now chemists turned it blue. It might have potential for consumers like you. Natural colorings for food and cosmetics are in demand. Biology’s blue pigments, however, are tough to bottle. The brilliant blues of jaybirds, butterflies and dragonflies are a consequence of light scattering, so there’s no pigment to isolate (SN: 6/30/17). Juicing blueberries isn’t an option “because the pigment doesn’t last, and its blue color can change or fade,” says Erick Leite Bastos, a chemist at Universidade de São Paulo in Brazil. Bastos and colleagues instead chemically modified a food color additive found in red beets to make blue, the team reports April 3 in Science Advances. Chemists can tune certain molecules’ color by adding alternating single and double bonds to their chemical structures. That can “create molecules that absorb yellow/orange light and, consequently, look blue,” Bastos says. The beet pigment already has some bonds in that alternating arrangement, but not nearly enough to appear blue. Bastos hypothesized...