New research finds a natural blue that could replace artificial colors


A pigment found in red cabbage could be used to make a long-lasting and stable natural blue color for food, according to new research published in the Science Advances journal.

The study was done by researchers from Mars Wrigley’s science and technology team; the Mars Advanced Research Institute (MARI); University of California, Davis’ Innovation Institute for Food and Health; Ohio State University; Nagoya University in Japan; University of Avignon in France; and SISSA University in Italy. It was funded by MARI and Mars Wrigley Science and Technology.

While many food companies have been moving toward natural colors, finding a natural replacement for blue has been particularly challenging. But food and ingredients manufacturers have been trying. According to an emailed statement from Mars Wrigley Senior Principal Scientist Rebecca Robbins, the team that published the report has been doing this research for more than a decade.

“After many years of hard work we have now discovered a unique anthocyanin, a type of naturally occurring pigment, in red cabbage,” she said. “It provides a natural alternative to artificial colorants, and a solution to the long-standing blue dye challenge facing the food industry. We used synthetic biology and computational design tools to determine the structure of the anthocyanin, which, thanks to its unique 3D inter-molecular arrangement, can be altered to produce a rare natural cyan blue color.”

Mars, Incorporated has an especially big stake in the search for a natural blue. In February 2016, the company announced a commitment to remove all artificial colors from its human food portfolio by February 2021 to meet evolving consumer preferences. Some of the company’s portfolio products, like Ben’s Originals side dishes and Tasty Bite’s Indian-inspired legumes and potatoes, could easily use natural colors. But under the company’s Mars Wrigley candy division, brightly colored confectionery brands including M&Ms and Skittles posed challenges. The company had a difficult time finding natural colors for many of its vivid candies that would appeal to consumers and that was available in a large enough supply.

“After many years of hard work we have now discovered a unique anthocyanin, a type of naturally occurring pigment, in red cabbage. It provides a natural alternative to artificial colorants, and a solution to the long-standing blue dye challenge facing the food industry.”

Rebecca Robbins

Senior principal scientist, Mars Wrigley

More recent consumer research also showed that people in the U.S. were not really concerned with artificial colors, a Mars spokesperson said. So the company stepped back a bit from its commitment. While Mars has removed all artificial colors from its dinnertime foods, in confectionery it is now pledging to use natural colors in some products, but will continue to use artificial ones in geographic areas where consumers don’t find them objectionable. The updated statement about artificial colors on Mars, Incorporated’s website says that the company made this choice to meet evolving consumer preferences. 

While Mars Wrigley’s rush for blue five years ago inspired ingredients makers to work on blue colors from spirulina algae, the new red cabbage solution is completely unique. And, if further study shows it to be as stable and effective as this first research report, it could change the way many food companies make blues and greens.

“Combining modern techniques from analytical chemistry, food science, biochemistry, synthetic biology, color science and computational chemistry, we discovered, characterized and defined a path to production for a naturally sourced cyan blue colorant whose color properties are nearly identical to those of the industry standard Brilliant Blue FCF (FD&C Blue No. 1),” the study says.

How does this work?

Scientists researching natural blue have long focused on anthocyanins — the naturally occurring pigments that give plants blue, purple and red colors. In an email, Robbins said the team was looking at where in the plant kingdom a stable blue for food could be found. Mars and Ohio State researchers narrowed the ideal sources down to red cabbage and purple sweet potato.

Taking a closer look at the anthocyanins in just those two plants, Robbins wrote that the pigments in red cabbage were found to be more stable — which is important because colors used in food need to maintain their hue in different conditions, including temperature, pH values and liquid or solid formats.

In past research, red cabbage’s anthocyanins were found to produce a blue that had a lot of violet, and that wasn’t stable at different pH levels. The research team behind this paper took a closer look into the molecules that formed the array of color in red cabbage, Robbins wrote, and found one particular molecule — referred to in the paper as P2 — that created the kind of blue for which the food industry has been searching.

Optional Caption

Markus U. (2019). “Red cabbage” [photograph]. Retrieved from Flickr.


Finding the P2 molecule was just the start. Researchers needed to know more about its structure and why it behaves the way it does, so the team brought in scientists with different areas of expertise for assistance. The University of Avignon scientists studied its chemical behavior, those at Nagoya University worked on determining its structure and SISSA experts did molecular modeling. Much of the paper published in the journal is a technical explanation of the pigment’s makeup and behavior.

When beginning this research, scientists used standard techniques to separate the P2 molecule from the rest of the material in cabbage, Robbins wrote. However, it is a very minor component in the makeup of red cabbage. Because of commonalities in the structure of all of the pigment molecules that are naturally occurring in red cabbage, UC Davis scientists using synthetic biology and computational protein design tools were able to create an enzymatic method of converting all of the anthocyanins in red cabbage to P2.

“Broadly, the research … demonstrates the power of a multidisciplinary strategy to solve a long-standing challenge in the food industry,” the paper says.

What’s next?

While this research is groundbreaking and could represent the beginning of a sea change in natural colors in food, there is still quite a lot that needs to be done before this blue makes it to the market.

This paper explains what the pigment is, how it behaves and how it can be sourced. But it hasn’t tested P2 as a coloring in specific applications. The pigment’s limitations are as yet unknown; other natural blue colors don’t always work well in liquids. And while the color is relatively stable in lab circumstances, its ability to maintain its hue in products including candies, ice cream and baked goods needs to be tested.

The color also needs to undergo proper vetting and regulatory approval by the Food and Drug Administration and other national governmental entities to ensure its safety.

It’s also not yet known how the color might be produced and commercialized. In terms of other natural blue colors, spirulina is cultivated, extracted and sold by many ingredients makers, while Archer Daniels Midland’s Wild Flavors and Specialty Ingredients has the patent for huito blue, a natural coloring from a tropical fruit. Robbins wrote that Mars is working with a collaborator to determine options for scale-up and commercialization of the red cabbage blue color.