Food dyes may offer a way to monitor food properties
A study presented during the Biophysical Society’s 61st Annual Meeting shows that Allura Red, a synthetic food and pharmaceutical color widely used within the United States, boasts properties that may make it and other food dyes appropriate as sensors or edible probes to monitor foods and pharmaceuticals.
A study presented during the Biophysical Society’s 61st Annual Meeting shows that Allura Red, a synthetic food and pharmaceutical color widely used within the United States, boasts properties that may make it and other food dyes appropriate as sensors or edible probes to monitor foods and pharmaceuticals. A team of researchers from Rutgers University, the University of Pennsylvania, and the University of Massachusetts, recently made this discovery during an extension of their work identifying and characterizing molecules in foods or food ingredients that might provide signals of food quality, stability, or safety.
It turns out that many molecules found in foods absorb ultraviolet or visible light and subsequently emit light as fluorescence. Because fluorescence is sensitive to the local chemical and physical environment, this emitted light can “report” on the local properties of the food, the pH, polarity, or in the case of Allura Red, local viscosity or thickness.
One food dye in particular—Sunset Yellow—only exhibited phosphorescence in the viscous solution. So, the researchers tested other dyes that tended to be non-fluorescent to see if they might fluoresce in viscous solutions. All the dyes they tested—Tartrazine, Fast Green, Allura Red, and others—showed properties that are sensitive to changes in viscosity.
Interestingly, the team identified other naturally occurring molecules. “Many naturally occurring molecules are sensitive to other physical and chemical properties important for food quality, so a generalized technique using naturally occurring food molecules—colors, flavors, vitamins, etc.—to monitor food quality is, in principle, possible,” said Richard Ludescher, dean of Academic Programs and professor of food science in the School of Environmental and Biological Sciences at Rutgers.
The study results showcase the potential of harnessing molecules that are already present in foods to monitor their basic physical and chemical properties. With optical sensing, such analysis could be achieved within mere seconds during manufacture—automatically and noninvasively replacing a measurement that previously might have required much more time.