| A new generation of eco-friendly packaging materials is required to improve food quality, safety, nutritional
value, shelf-life, and sustainability. In this study, a novel multifunctional halochromic packaging material was
fabricated by immobilizing saffron petal anthocyanins within a biopolymer matrix consisting of chitosan
nanofibers and methyl cellulose. The gas barrier, light screening, physico-mechanical, and optical properties of
the films were then characterized. The color of the multifunctional films depended on pH and ammonia gas levels
as a result of changes in the molecular structure of the anthocyanins. The films changed from reddish/pink to
violet to green to yellow as the pH was increased from 1 to 14, and went from violet to green/yellow when the
ammonia vapor concentration was increased. Incorporation of the anthocyanins into the films also increased
their tensile strength, light screening properties, antimicrobial activity (E. coli & S. aureus), and antioxidant
activity (DPPH radical scavenging). Analysis of the microstructure and spectroscopic properties of the films
showed that the anthocyanins were compatible with the surrounding biopolymer matrix. Finally, we showed that
the anthocyanin-loaded films could be used as smart packaging materials for monitoring changes in the freshness
of a model meat product (lamb) during storage. |