It may seem like a basic color, but blue is actually rather rare in the natural world. That complicates the search for natural blue food colorings, but now a team of scientists has found a promising candidate hiding in red cabbage.
For decades, concerns have been raised about the safety of synthetic food dyes, and while the evidence against them is still unclear, natural colorings are generally preferred. Most of these pigments are sourced from plants, although a few come from crushed insects. But, frustratingly, not all colors are easy to find in these places.
Now, a natural brilliant blue has finally been produced. The color came from a type of molecule called an anthocyanin, which give red, purple, blue or black colorings to certain flowers and food plants like blackberries, raspberries, blueberries, cherries, and red cabbage.
That last plant is what finally gave up the secret. As you might expect, most of the anthocyanins in red cabbage are red or purple, but there are tiny amounts of blue in there too. After about a decade of trying, a team of scientists from a range of institutions and food companies has now managed to extract useful amounts of blue by converting other anthocyanins.
Doing so required exactly the right enzyme, so the team screened a library of millions of them, and used computational simulations to explore about 100 quintillion potential protein sequences. Eventually, they were able to design the perfect enzyme for the job of converting the red and purple anthocyanins into blue ones.
The end result, the team says, is a natural cyan dye equivalent to the widely used synthetic FD&C Blue No. 1. In tests, the color gave ice cream a striking blue tinge that’s honestly hard to believe is natural.
The researchers have founded a startup company called Peak B to attempt to commercialize the new natural blue food coloring.
Natural brilliant blue food coloring wrung out of red cabbage [New Atlas]