Food Dyes Show Promise as Quality Probes

Food dyes may be useful for more than just giving your cherry Jell-O that vivid red hue. In research described at the annual meeting of the Biophysical Society in early February, a team of food scientists from Rutgers University in New Jersey has found that common food dyes have the potential for use as edible probes of food quality.

Standard fluorescent dyes used as probes in other fields are generally unsuitable for food quality testing, as they are either too toxic for human consumption or too expensive. But the Rutgers scientists say that the edible colors that already either occur naturally in, or are added to, many foods have the potential to act as fluorescent probes.

“Almost every food you eat is fluorescent under some circumstances,” says Richard Ludescher, PhD, a professor of food science at Rutgers. “With a range of applications, we are trying to establish the idea of using molecules that are naturally in or routinely added to food as intrinsic sensors of the quality of the food.”

Sarah Waxman, an undergraduate student in Dr. Ludescher’s lab, presented preliminary findings at the Biophysical Society meeting. The group tested the fluorescent properties of five edible food colors commonly added to food or medications consumed by humans: Allura Red, Sunset Yellow, Brilliant Blue, Fast Green, and a yellow dye called Tartrazine. All five colors fluoresced in a way that was easily distinguishable from the background; they emitted almost no light in pure water, but the light intensity increased when the dyes were added to thicker solutions.

“We’ve established that these molecules respond to viscosity in simple solutions like sugar water and glycerol water,” says Dr. Ludescher. “Next, we need to find out how they respond in more complicated compositions like foods—a pudding, for example. Could we develop a probe for pudding that allows you to measure its viscosity during manufacture?”

The group’s work is supported by funding from the USDA.

Shaw writes frequently about science, medicine, and health while serving as a regular contributor on notable medical publications.