SCIENTISTS FOUND SOURCE OF SAFE BLUE FOOD COLOURING IN A RED CABBAGE.
New, true blue could eliminate the need for artificial food colouring
Rare in nature, a source of natural blue for food colouring has proven to be equally elusive in the lab. From blue rice to butterfly pea powder bubble tea — blue foods are in demand. But as food companies increasingly phase out artificial colours in packaged goods, a natural substitute for synthetic “brilliant blue” has proven hard to come by.
Smarties fans have felt the sting of such food science limitations firsthand. In 2006, amid health concerns over artificial colourings, Nestlé temporarily axed blue Smarties from the pack. Replaced with pallid white, it took nearly three years for its spirulina-tinted comeback. But the freshwater algae is far from a magic blue bullet.
Now, after more than a decade of research, an international team of scientists has found a natural blue candidate in red cabbage. The study, published in Science Advances and led by Pamela Denish at the University of California, Davis, shows how a natural blue pigment (a type of anthocyanin molecule) in red cabbage can be used to make a long-lasting colouring in large quantities.
“It provides a natural alternative to artificial colourants, and a solution to the long-standing blue dye challenge facing the food industry,” Rebecca Robbins, Mars Wrigley senior principal scientist and one of the authors of the paper, told Food Dive. “We used synthetic biology and computational design tools to determine the structure of the anthocyanin, which, thanks to its unique 3D intermolecular arrangement, can be altered to produce a rare natural cyan blue colour.”
Many of the true-blue, edible foods found in nature don’t produce blue colours, but reds and purples, said Denish, a graduate student working with Prof. Justin Siegel at the UC Davis Department of Chemistry and Innovation Institute for Food and Health. Consider the deep purple tint of blueberry juice, for example, or ruby-red hue of haskap nectar.
Synthetic “brilliant blue” (a.k.a. Blue No. 1) was originally made from coal tar, but is now mostly an oil-based additive. Its brilliance is key: while vibrant blue foods signal novelty; other shades can suppress the appetite, an instinctive response to their presence in moulds, poisonous fruit or spoiled meat, according to Food Dive.
Developing the right shade of natural blue also affects colour mixing, Siegel said. If the colour is off, it will result in “muddy, brown colours” rather than green when combined with yellow.
Prior to the new findings, spirulina — used in the natural blue Smarties formulation as well as many other foods and drinks, including energy bars and smoothies — was deemed to be the closest colour match to Blue No. 1.
Mars, which created the first Fda-approved natural blue food colour using the algae, announced its intention to remove all artificial food colourings in 2016. Spirulina may achieve a desirably intense blue hue, but it’s unpredictable, prone to blotchiness and can have an unpleasant taste, Food Dive reports.
There’s also the issue of availability. In order to give just its blue M&MS a spirulina makeover, a Mars executive told The New York
IT PROVIDES A NATURAL ALTERNATIVE TO ARTIFICIAL COLOURANTS.
Times in 2016, the company would need twice the global supply.
The new cyan blue researchers identified is only present in small amounts in red cabbage, but using an enzyme they developed, they were able to produce larger quantities of the colour compound. They then used the natural colouring to make blue ice cream, doughnut icing and sugar-coated lentils, which held their hue for 30 days, New Scientist reports.
Denish and Siegel have founded a startup, Peak B, to focus on developing the stable, natural food colouring for commercial use. Siegel noted that similar enzymatic conversions are commonly used in food production, including cheesemaking.
The natural food dye has yet to be tested for its safety, but Kumi Yoshida at Nagoya University in Japan, one of the study’s authors, told New Scientist that she doesn’t expect any issues due to its established use: “Red cabbage anthocyanins have a long, long history in our diets.”