Natural hydrogels for active, intelligent and smart food packaging: Advances, challenges, and future perspectives

Abstract

The global food industry is evolving rapidly, driving increasing demand for functional and eco-friendly food packaging. Active, intelligent, and smart food packaging materials (AIS-FPMs) have become a pivotal research field. Among these, natural hydrogels (NHs) have attracted particular attention due to their tunable physicochemical properties, bio-based origins, and favorable environmental performance. This review comprehensively summarizes the latest advances in NHs-based AIS-FPMs, focusing on their structural advantages, functional drawbacks, industrialization obstacles, and improvement strategies, and elucidates the mechanisms underlying their stimuli-responsive behavior and barrier performance through representative case studies. Key observations: (1) the adjustable porosity and natural biodegradability of hydrogels support sustainability goals in modern packaging; (2) their responsiveness to environmental stimuli, such as pH and temperature enables real-time monitoring of food quality; (3) inherent limitations of NHs include insufficient mechanical strength, high moisture sensitivity (e.g., excessive swelling in high-humidity environments), and poor long-term stability; and (4) strategies such as nano-reinforcement and optimized crosslinking have been explored to improve performance, although these approaches may involve trade-offs in optical clarity or processing complexity, and (5) industrial-scale production remains challenging due to complex fabrication processes, low continuous throughput, poor compatibility with high-speed packaging lines, and regulatory hurdles related to food-contact safety. The review also discusses a development framework that integrates biomimetic design principles with emerging manufacturing methods to guide the future development of NHs-based AIS-FPMs. Promising future research directions include integrating multifunctional sensors, developing bio-based nanocomposites, and simplifying fabrication processes to overcome industrialization barriers.