Oxygen indicator for intelligent food packaging
Intelligent packaging helps in communicating the quality of packed food to assure its safety. Now, a gallic acid monohydrate (GA)-based moisture activated oxygen indicator label was developed to visualize the interaction of food with oxygen. Coating solutions were formulated using cellulose acetate, ethyl acetate/ethanol, and different concentrations of GA. It was bar-coated onto a paper substrate using a layer-by-layer technique and dried at ambient conditions.
Oxygen indicator in food packaging applications
Upon exposure to varying alkaline pH at atmospheric oxygen, the label exhibited a color change from green to yellow as observed in UV–visible spectra because of a change in the structure of GA. Rheological studies showed GA20% has better viscosity for coating. FESEM and AFM images confirmed its smoother surface with a decrease in roughness by approximately 60%. ΔE values at pH 8 have the highest color difference at all concentrations. Therefore, gallic acid has the potential to be used as an oxygen indicator in food packaging applications.
The study has been published in Journal of Coatings Technology and Research, Volume 19, September 2022.