Finding a natural cyan blue dye that is equivalent to FD&C Blue No. 1 has been a challenge for the entire industry and the subject of research programs around the world. Now, an international team of researchers has discovered a promising cyan blue dye that is obtained naturally from the pigments of red cabbage that, if proven to be safe for food use, will be the best natural alternative to the blue coloring of food.
The study was carried out with some of the red cabbage’s water-soluble pigments, anthocyanins, which are mainly red and purple. In this type of cabbage, natural blue is only found in small amounts and it is too violet to replace the artificial coloring. For a decade, a team led by scientists from the Mars Advanced Research Institute and Mars Wrigley Science and Technology has worked in collaboration with the UC Davis Innovation Institute for Food and Health, Ohio State University, Nagoya University (Japan ), the University of Avignon (France), the SISSA University (Italy), and chemists from the Autonomous University of Barcelona (UAB) to isolate a blue anthocyanin from red cabbage.
The researchers of the study, which was published in the Science Advances journal, have discovered a way to convert other anthocyanins in cabbage into a blue compound.
The dye was obtained thanks to an enzyme that converts a series of anthocyanins into one that has an exact blue color and that remains very stable over time (its color only decreased by 14% after 55 days in sugar syrup).
To achieve this, the scientists screened millions of enzymes for candidates that could do the job and tested a small number in the lab.
Based on these results, using computational methods, they searched an enormous number of possible protein sequences – 1,020, more than the number of stars in the universe – to design an enzyme that would carry out the conversion efficiently.
With this enzyme (P2), they were able to convert the tiny fraction of blue anthocyanin extracted from the red cabbage into a primary product, which allowed the institute’s researchers and other collaborators to characterize the new dye, to produce it in sufficient quantities and use it in the food industry.
The study also demonstrated the ability of the dye to create blue and green colors in various foods and confectionery, where it also showed excellent stability for 30 days when stored at room temperature.
According to the researchers, they still need to carry out toxicity studies to define the new dye’s use limitations and food safety precautions. However, they have already founded PeakB, a startup that will develop this technology for commercial applications.