Food dyes to improve product quality
11 Feb 2015
A team of researchers at Rutgers University, US is investigating whether common food dyes could act as optical probes to help improve the quality of food.
Results from initial testing found that the fluorescence of five common food colours increases as the viscosity of the surrounding fluid increases - meaning the dyes could potentially act as embedded sensors for food’s physical consistency in products such as yogurt or strawberry milk.
“Using food dyes as probes could be a less invasive and more accurate way to test food’s physical properties
Rutgers undergraduate Sarah Waxman
“Fluorescent probes have been used in many applications, but the idea of using food colours for this purpose is new,” said Sarah Waxman, an undergraduate student at Rutgers University.
Waxman, alongside a team of researchers at the university, tested the fluorescent properties of five edible food colours that are routinely added to food or pharmaceuticals: Allura Red, Sunset Yellow, Brilliant Blue, Fast Green and Tartrazine, a yellow-coloured dye.
By mixing the dyes in solutions of varying consistencies, the researchers found that all five dyes fluoresce at a significantly different colour than the light that is used to excite them or the fluorescence of other components in the environment, meaning the emitted signal could be easily distinguished from the background.
The researchers also found that although the food colours emitted practically no light when mixed in pure water, the light intensity increased as the solutions thickened.
Increased levels of fluorescence could be attributed to the way molecules move differently in different liquids, the researchers said.
The change in the dyes’ fluorescence could therefore give clues about the consistency and molecular arrangement of the fluid surrounding the dye particles, Waxman explained.
“A viscometer, which is a typical instrument to test the thickness of food, requires separating and ultimately discarding a large sample size and could report distorted numbers due to factors like the slippage of layers in the fluid,” Waxman said.
“Using food dyes as probes could be a less invasive and more accurate way to test food’s physical properties,” Waxman said.
