Intelligent packaging films based on anthocyanins: A review of structural properties, biodegradable polymers, application and prospects in food freshness monitoring

In response to global food safety concerns, this review presents a systematic evaluation of anthocyanin-based packaging films, emphasizing the innovative integration of diverse biopolymer matrices and targeted stabilization strategies. The research gap addressed herein lies in the synergistic mechanisms between anthocyanins and multi-component matrices, which are critical for enhancing film performance. Current advances in molecular stabilization techniques are critically synthesized, such as co-pigmentation and nano-encapsulation, providing a new perspective on maintaining colorimetric accuracy under complex storage conditions. The paper highlights the originality of adopting multi-responsive systems that transition from passive indicators to active-intelligent frameworks capable of both real-time freshness monitoring. Characterization insights, particularly regarding intermolecular interactions and structural morphology, are discussed to substantiate the film's functional superiority. Finally, the review addresses existing limitations regarding thermal sensitivity and outlines a roadmap for industrial-scale production and digital integration. This comprehensive analysis provides a high-value reference for developing sustainable, next-generation intelligent packaging systems. • Anthocyanins structure, properties and stability were reviewed. • Gas indicators/sensors and biodegradable polymer-based films were described. • Anthocyanins-loaded films for food freshness monitoring were stated. • Challenges and future work of anthocyanins-loaded films were discussed.