Chitosan, starch, cellulose, and alginate-based biodegradable nanocomposite food coatings: Interfacial modifications, quality metrics, and lifecycle perspectives: A review

Biodegradable nanocomposite food coatings based on renewable polymers offer promising alternatives to conventional petroleum-derived packaging, but their practical application requires simultaneous consideration of performance, safety, processing, and lifecycle sustainability. This review critically evaluates chitosan, starch, cellulose, and alginate-based coatings, emphasizing how nanomaterial incorporation and interfacial modification influence structure-property relationships and food-packaging performance. Unlike conventional reviews focused primarily on individual polymers or nanocomposite formulations, this work integrates interfacial chemistry, standardized coating-quality assessment, food functionality, safety, lifecycle performance, and industrial translation within a comparative framework. A nine-parameter quality framework is presented covering mechanical, optical, moisture, barrier, solubility, gas-permeability, and rheological characteristics, together with relevant test methods and application-dependent criteria. The review further examines nanoparticle dispersion, aggregation, loading effects, and tortuous-path mechanisms, highlighting performance trade-offs among mechanical strength, barrier properties, functionality, and processability. Particular attention is given to nanoparticle migration and safety considerations associated with Ag, ZnO, and TiO₂, as well as the distinction between biobased, biodegradable, compostable, and environmentally degradable materials. Lifecycle and techno-economic perspectives demonstrate that environmental benefits may be influenced by nanofiller production, processing, transportation, and end-of-life management. Overall, successful industrial translation requires balancing performance, safety, reproducibility, cost, regulatory compliance, and verified lifecycle sustainability.