pH-responsive composite konjac glucomannan/xanthan gum film incorporated lysozyme fibril for the monitoring of chicken breast freshness.

A pH responsive composite film was developed by incorporating cyanidin (CY) and egg white lysozyme fibril into konjac glucomannan (KGM) and xanthan gum (XG) matrix to monitor the chicken breast freshness in this work. The physicochemical properties of the films, especially pH sensitivity, evaluated by color difference and visual color change under different pH values, were first explored. The freshness changes of chicken breast sealed with the composite films were also analyzed. Hydrogen bonding and electrostatic interaction formed between the components of the composite film. Moreover, the characterizations of pH responsiveness, thermal stability, and barrier property indicated the benefits of incorporating CY and lysozyme fibril into KGM/XG films. The KGM/XG/lysozyme fibril/CY (KXLCY) film showed superior biodegradability in soil. KXLCY composite film reduced the weight loss and delayed the spoilage and fat oxidation rate of chicken breast. In addition, the color of KXLCY film changed from purple red to purple and then to blue during the storage of the packaged chicken breast, indicating a real-time freshness monitoring effect. This work provided a solid scientific foundation for the development of active pH intelligent colorimetric films and their application in food freshness evaluation.