Smart Adsorption-Based Nanocatalysts for Active Food Packaging: A Critical Look at the Gap Between Concept and Application.

Conventional food packaging cannot actively regulate spoilage-related molecules such as ethylene and volatile organic compounds that accumulate inside sealed packages. Smart adsorption based nanocatalysts (SABNs) integrate adsorptive scaffolds, catalytic centers, and stimuli responsive triggers to progressively remove these spoilage markers. This review establishes a unified three pillar framework and critically examines how adsorption, catalytic degradation, and regeneration cycles are proposed to function under food-relevant conditions. Across major food categories, reported photocatalytic systems achieve ethylene removal efficiencies of 50% to 90% and extend shelf life by 1 to 5 days under controlled light and temperature. However, performance declines sharply under the dark, humid, and refrigerated conditions typical of real supply chains. A systematic evidence level grading of twelve representative SABN systems reveals that the majority cluster at levels L3 and L4, while none has yet reached level L5, which requires both standardized migration testing and sensory evaluation. Key barriers, including nanoparticle migration, fragmented regulation, scalability, and life-cycle impacts, are assessed. By introducing explicit inclusion/exclusion criteria and a six-level evidence grading framework, this review maps critical gaps in migration data and cold-chain validation and outlines a staged roadmap toward regulation-ready active packaging technologies.