Algae Yields New, Improved Blue Food Dye

Cornell food scientists have created a natural blue food dye made of algae protein that could replace petroleum-based artificial food colorants with a stable, adaptable option.

The research published July 24 in the journal Food Hydrocolloids.

Phycocyanin (PC), a protein in algae, can be used as a vibrant blue food colorant, and can also replace synthetic emulsifiers, said Alireza Abbaspourrad, the Yongkeun Joh Associate Professor of Food Chemistry and Ingredient Technology in the Department of Food Science in the College of Agriculture and Life Sciences, and corresponding author of the research.

Phycocyanin, a protein in algae, can be used as a vibrant blue food colorant.

Credit: Sreang Hok/Cornell University

Phycocyanin, a protein in algae, can be used as a vibrant blue food colorant.

"Consumers don't want artificial ingredients in their food," said Qike Li, first author on the paper and a doctoral candidate in Abbaspourrad's lab. "They want something healthier and more natural. Specifically, they want to see a 'clean label,' which is a major reason we have chosen to work to increase the functionality of phycocyanin as a colorant and emulsifier."

On its own, this extract from algae is sensitive to heat during processing and light during storage. This lack of stability makes it challenging to integrate into food formulations, Li said.

Their goal was to dissect PC into its building blocks and create a more stable form. They used a denaturant to reorganize it from large and uneven polymers into smaller and more uniform components, which exhibit a higher emulsifying capacity, Li said. These uniform particles create emulsions, which present a vibrant natural blue color and enable the protection and delivery of nutrients in oil.

They then analyzed the results with a technique called small angle X-ray scattering (SAXS), used to see the structure of materials at the nanoscale.

"It's like using a magnifying glass to see and understand changes in protein structure," Abbaspourrad said. "Our aim is to increase the functionality of phycocyanin as a colorant, emulsifier and antioxidant, so that on the list of ingredients, it could replace multiple synthetic items."

Removing artificial food colorings from commercial foods has become a bipartisan hot-button issue, with Red No. 3 banned and Blue No. 1, Blue No. 2, Green No. 3, Red No. 40, Yellow No. 5 and Yellow No. 6 on the chopping block in many state bills. U.S. Secretary of Health and Human Services Robert F. Kennedy Jr. has announced an plan to phase out certain artificial food dyes from the nation's food supply and medications.

And consumers are eager to see the artificial blue dyes removed from common cereals, fruit snacks, baked goods, ice cream and candies.

But the food industry has cautioned that natural substitutes are often less stable, less vibrant and more expensive. Natural blue dyes are especially hard to create because blue pigments are rare in nature. The color of the sky or the vibrant blue of a morpho butterfly's wings is the result of how light is scattered or reflected rather than due to a blue pigment.

The crude protein extracts of spirulina, where PC is a key component, are increasingly being studied and incorporated into foods. It is used as the substitute for artificial blue coloring in M&Ms. But the Cornell team believes PC may have superior properties and utility.

Abbaspourrad said the cost associated with adoption of phycocyanin in place of artificial blue dyes is likely reasonable, considering its health benefits. Next steps include scaling it up with a food industry partner.

Funding for this research came from the U.S. Department of Agriculture.

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