Fabrication and validation of CO2-sensitive indicator to monitor the freshness of poultry meat

Abstract

Three-layer CO2-sensitive intelligent labels consisting of PET as transparent gas impermeable film, the color changing layer with pH dyes (bromothymol blue (BTB) and phenol red (PR)) immobilized with a cellulose-based binder, and a white PE film as the gas permeable inner layer. The intelligent labels were implemented in PA/PE bags for CO2 simulation at concentrations of 0–30 %, and color change (∆E and ∆RGB) was monitored at 4 °C and 25 °C for 24 h. Chicken breast was packaged with PA/PE bags integrated with the intelligent labels and the color change was monitored at 10 °C for 4 days. BTB-based indicators showed a higher color difference than PR-based indicators in simulation and poultry packaging. However, phenol red-based indicators showed a more distinct and noticeable color change. The increase in CO2 correlates well with the color change. PR and BTB-based pH sensitive dyes are successfully used to monitor poultry meat spoilage in real packaging conditions.