25 Feb 2026 Can structural colour replace titanium dioxide in food?

This US start-up is betting on what’s known as the butterfly effect….

Food formulators now have an array of options to replace synthetic dyes. But when it comes to titanium dioxide — white pigment now banned in the EU in foods and under threat in some US states — the toolbox is more limited.

Existing solutions range from calcium carbonate, calcium phosphate, and modified starches to new cellulose-based pigments inspired by beetles. But there is no single product that can replace it across every application.

The Massachusetts-based Mirra is looking for more effective options with this a novel approach.

What is structural colour?

Colour is not an intrinsic property of objects but arises from the interaction between a light source, the object’s structure or chemistry, and the observer’s eyes/brain. However, structural colours are different to pigments and dyes currently used to colour foods or textiles, Mirra CEO Elizabeth Bridges told AgFunderNews.

Structural colour — which is most advanced in paint and coatings but has been demonstrated by Nike in footwear prototypes — arises when micro- or nanostructures interact with light in a way that selectively reflects certain wavelengths.

Butterflies, for example, create structural colours from complex nanostructures on their wing scales that manipulate light through interference and diffraction.

Food pigments, in contrast, are seen because their molecules absorb specific wavelengths of light and reflect the rest, she explained.

Plant-based pigments can degrade with changes in light, pH, heat, or physical stress, and often have to be included in high amounts to achieve the vibrancy of synthetic dyes, which can negatively impact flavour or texture. However, structural colours are more stable, she claimed.

How it works

Mirra designs specific colours by adjusting the size, spacing, and orientation of its raw materials (undisclosed vegetable proteins), starting with an alternative to titanium dioxide.

“You’re assembling them in a way to create a specific refraction pattern of light, whereas an azo dye for example, will chemically bonding to a natural fibre to create a colour in textiles, for example,” said Bridges.

“If you’ve seen a hummingbird or a butterfly, if you change the position you’re looking from, you’ll see a different colour. This is an effect you can cultivate with structural colour, but you can also create a less directive pattern enabling you to have a single colour.”

The tech was developed by Mirra’s chief scientific advisor Dr Leila Deravi, associate professor in the Department of Chemistry and Chemical Biology at Northeastern University in Boston, and Mirra has the exclusive option to license it, she added.

Published literature describes new “solution-processed” methods that create structural colour by letting particles self-assemble from a liquid (solution) into light-scattering micro- or nanostructures as the solvent evaporates or conditions change. Other methods rely on top-down fabrication techniques to physically create target structures.

Bridges did not say how Mirra is making its structural colours, but added: “We have a patent pending, so I have to be a little bit sensitive about what I share. We’re taking the process we’ve developed in the lab and trying to understand what that would look like at full scale but it’s not an expensive and complicated process.

“There is a kind of stigma attached to structural colour in that it’s expensive to make, but one of the breakthroughs of the process that Dr Deravi has developed is that we believe we’re able to meet price parity rate at scale.”…

Read the full article here: AgFunderNews