A research team from the University of Seville (US) has obtained new food colorings with greater stability, increasing the preservation properties of anthocyanins, the pigments responsible for the characteristic color of blueberries, by up to 40%.

This advance could open the door to a new generation of natural red and blue substances for beverages, dairy products, pastries or even cosmetics, the Ministry of University, Research and Innovation said in a statement.

Furthermore, by using blueberry skins, an agro-industrial waste product, the research proposes a circular economy model that takes advantage of food waste and turns it into high-value ingredients.

In an article published in the journal Food Research International, experts demonstrate the effectiveness of this method in an isotonic drink in the laboratory.

In recent years, the food industry has sought to replace synthetic colorants with natural ones; anthocyanins present in red fruits such as blueberries represent a good alternative as natural pigments, although they are highly unstable, since they degrade with heat, light or changes in pH, quickly losing their vibrant color.

“The big problem with natural dyes is that they don’t withstand industrial processes well. We wanted to find a way to protect them without altering their natural origin, and we’ve found a possible way to solve this problem,” Belén Gordillo, a researcher at the University of Seville, told the Descubre Foundation, an organization under the auspices of the Regional Ministry of Universities.

In this study, experts have combined two techniques to improve the color intensity and stability of anthocyanins.

On one hand, there is copigmentation with ferulic acid, an antioxidant compound present in fruits that acts as a protective partner, helping to maintain its bright tone for longer.

On the other hand, microencapsulation, which consists of wrapping the anthocyanins with a thin layer of maltodextrin, a type of sugar that protects it from physical degradation such as exposure to heat, light and air, as if it were an invisible capsule.

“The experiment revealed that by reducing the proportion of maltodextrin and adding ferulic acid, the particles retained more than 40% of the original anthocyanins and showed greater antioxidant capacity. The color remained stable, a rare feat for natural colorants,” the researcher added.

The researchers began by extracting anthocyanins from the blueberry skin, as it is the part richest in color, and prepared a solution to which they added ferulic acid, so that it would act as a color protector.

They then moved on to the second part of the process called microencapsulation, for which they mixed the anthocyanin-ferulic acid solution with an edible substance, maltodextrin, and subjected it to a spray drying process.

Finally, the scientists analyzed the properties of this powder, verifying that the combination with ferulic acid followed by microencapsulation coating offered the greatest protection of the color against the passage of time and adverse conditions.

The researchers propose to continue their work to make the transition of this dual strategy possible at an industrial level, optimizing costs, coating materials, and drying conditions.

They also suggest exploring other encapsulating agents and natural copigments in order to further improve color protection and adapt the process to different types of food.