Colorimetric array freshness indicator and digital color processing for monitoring the freshness of packaged chicken breast

A colorimetric array freshness indicator was developed to monitor chicken breast spoilage, consisting of an inner poly(ether-block-amide) (PEBA) film, a color-changing layer of eight polymer-immobilized pH dyes, and an outer poly(ethylene terephthalate) film. Simulated experiments with trimethyl amine (TMA) revealed the necessary color changes and the optimum dye concentration for the expected quality range for stored chicken breast was determined. The optimized colorimetric array freshness indicator was then applied to chicken breast packaging and digital images for its color response were acquired using a smartphone camera over storage time. The obtained data were analyzed by both the newly developed chromatic factor and principal component analysis. Chicken breast samples stored at 4 °C and 10 °C could be categorized into two groups, fresh and spoiled states over the storage time. The chromatic parameter X was well correlated with the microorganism counts as well as total volatile base nitrogen (TVBN) and CO₂ from the chicken meat samples. Future implementation of the indicator in combination with a smartphone application could provide a low-cost, specific, and sensitive monitoring method for food product freshness.