Novel color stability and colorimetry-enhanced intelligent CO2 indicators by metal complexation of anthocyanins for monitoring chicken freshness

[Display omitted] •The initial color of black goji berry anthocyanins (BGA) changed after storage.•A metal complexation process successfully improved the color stability of BGA.•Chelated BGAs showed distinctive color changes at different CO2 concentrations.•Food quality indicatives and indicator color parameters showed a high correlation.•Developed CO2 indicator demonstrated a potential use in food quality detection. This study aims to improve the color stability of anthocyanins and develop a CO2-sensitive indicator based on black goji anthocyanin (BGA) extract. Although the BGA extracts showed distinct color changes, such as red–purple–blue, their intrinsic color diminished after 24 h. A metal complexation method was used for the high color stability of BGA. BGA extracts were chelated with various concentrations of Al3+ [0 – 20% (w/w)]. It showed high color stability and strong intensity in a dose-dependent manner. A CO2-sensitive indicator sachet was developed using hydroxypropyl methylcellulose hydrogel, based on 5% (w/w) Al3+-BGA complexes. The indicator was applied to the chicken breast and detected its spoilage after 3 days with its changing color to greyish blue, due to the microbial growth to 7.00 log CFU/g. These results demonstrated the possibility of chelated anthocyanin complexes as indicating dyes and the ability to monitor the food quality changes through noticeable color changes.