Mirra wants to use physics to make food vibrant

Titanium dioxide’s journey from the Earth’s crust to our lips is a long one.

The food additive—which is used in foods like candy, cottage cheese, and frosting—starts as a metal found in a handful of minerals. It’s mined via earth blasting and drilling, and then processed into titanium dioxide. Once in the form of a fine, white powder, it can be added as a pigment to foods to make them look brighter and more opaque.

The EU banned titanium dioxide in 2022 because there wasn’t enough evidence to prove it wasn’t toxic, but the US Food and Drug Administration allows it to be used in foods in quantities up to 1% of a product’s weight. Beyond its toxic uncertainty, the presence and use of titanium dioxide has far-reaching effects: Mining and processing the material is carbon-intensive, and creating it synthetically generates emissions, too.

That’s why Mirra is working to replace titanium dioxide and petroleum-based food dyes using structural color, a physical process found in nature (think the vibrant colors of butterflies and birds). The team of scientists and innovators recently won the Massachusetts Clean Energy Center’s Climatetech Studio Showcase with technology they originated at Northeastern University. According to COO Elizabeth Bridges, Mirra will be able to better color foods than alternative food dyes, which tend to fade in the harsh conditions of food processing, like high temperatures, UV exposure, and changing pH levels.

“We’re really focused on taking vegetables and foods and using them as food dyes,” Bridges said, “in a way that allows the food industry to continue the level of vibrant color and conditions that they’re using in their products today.”

Structural color: But Mirra’s alternatives to food dyes don’t involve dyes at all. While dyes change an object’s color via absorption, structural color changes an object’s color by reflecting light in a particular wavelength, making it look like a particular color.

“Instead of having a dye that’s seeping into additional particles, what this structural color is able to do is control the way that light bounces off of the particles,” Bridges told Tech Brew. “So it’s changing the physics of the way that light interacts with that food, and it makes it a really stable, beefed up version of color.”

The structures that light bounces off of are smaller than a human hair and can be made using polymers. Mirra, in particular, will be using vegetables to create the structures that reflect light to change the color of foods.

Structural color can only be viewed using nanotechnology, so humans’ ability to study and reproduce it is fairly recent and based on technological advances. Rupa Darji, an industrial scientist at chemical manufacturing giant BASF, told Tech Brew that structurally colored products offer a market edge, even though replacing dyes would be “extremely challenging.”

“Humans would love to recreate something that nature does,” she said. “The idea that you can have a color not fade, it’s a huge advantage.”

From theory to practice: Though Mirra has promising market potential and says the products will be priced at “parity” with natural dyes, getting FDA approval could be tricky. Government agencies may regulate green tech products like Mirra differently from their traditional counterparts, and mass layoffs have seriously affected agency workforces. That said, the FDA, alongside the Department of Health and Human Services, has enacted policies to “phase out petroleum-based synthetic dyes” from US foods as part of the Trump administration’s “Make America Healthy Again” initiative.

“For too long, some food producers have been feeding Americans petroleum-based chemicals without their knowledge or consent,” HHS Secretary Robert F. Kennedy Jr. said in a statement earlier this year. “That era is coming to an end.”

For Mirra CEO Kirthika Padmanabhan, though, the mission is about much more than replacing food dyes—there are future opportunities to expand into textiles, ink, and pharmaceutical products, too.

“It’s a climate issue because we’re replacing petroleum and mined stuff. It’s a health issue because kids are eating this,” she told Tech Brew. “The story of Mirra is that this is an intersectional impact, starting with food, because food has the most pressing need right now.”