Colorimetric pH Sensitive Smart Film Based on Carrageenan Containing Quercetin or Eucalyptus Extract for Freshness Monitoring of Chicken Meat

Abstract Utilizing natural flavonoid indicators in marine-derived biopolymers to develop new biomaterials for food packaging that provide information about the quality of food products can inform the customer about food safety and diminish food waste. Herein, two novel smart pH-sensitive hydrogel films composed of κ-carrageenan (CG) combined with quercetin (QUE) or eucalyptus leaf extract (ELE) were extended for freshness information of chicken meat at room temperature. As quality indicators, the color changes of the hydrogel films through colorimetric and UV-Vis spectroscopy at pH 1–12 and TVB-N (total volatile basic nitrogen) were investigated. The films’ transparency, mechanical, antibacterial activity, and morphology were investigated. The results showed that the CG film with 0.3% QUE performs best. The CG film containing QUE or ELE had good antibacterial activity and preserved and controlled the freshness of chicken meat. In the case of engaging CG films, they showed visible color changes in informing the freshness of the chicken. The comparison of the film containing QUE and the ELE states that the film containing the ELE had a greater effect in preventing chicken spoilage and revealed distinguished pH-responsive color changes.