Recent advances in biomass-based polymers with UV-shielding function for sustainable food packaging

The development of high-performance and environmentally sustainable packaging is still a challenge in the modern food industry. Ultraviolet (UV) radiation is a major factor accelerating food spoilage through photo-oxidation, leading to nutrient loss, discoloration, off-flavor development, and then potential safety risks. Bio-based polymers with tailored UV-shielding performance have therefore attracted the attention of many researchers. This review constructed a new frame of structure-property-function relationships based on the comparison of current research. This work elucidated the relationships between molecular architectures of UV absorbers and bio-based polymers and UV-shielding mechanisms that can support the rational design of such materials in the packaging. Moreover, the trade-offs among UV-shielding efficiency, optical clarity and mechanical integrity and the gap in the migration assessment of additives were discussed. The types of UV-shielding agents, including inorganic nanoparticles, synthetic organic absorbers and natural compounds, have important effects on the shielding efficiency, compatibility, safety and sustainability of obtained UV-shielding packaging. In addition, suitable modification strategies and processing techniques can optimize the UV-shielding performance of target products. The UV-shielding efficacy, antioxidant activity, antibacterial activity and mechanical properties of these typical packaging materials were compared in detail. Furthermore, the trends toward multifunctional and intelligent packaging systems are highlighted. Finally, this review outlines future research directions aimed at facilitating the commercialization of bio-based polymer UV-shielding packaging with high performance. Thus, this work can provide an accessible route for the development of next-generation sustainable food packaging.