Valorizing animal waste protein through spinning: sustainable nanofiber innovation for advanced food packaging

This review critically assesses the valorization of animal waste proteins (collagen, gelatin, casein, keratin, and silk fibroin) into advanced food packaging nanofibers via electrospinning, solution blow spinning, and centrifugal spinning. This work details the processing parameters and protein-specific adaptations enabling the fabrication of ultrafine fibers with enhanced mechanical strength, tunable moisture/oxygen barriers, and a high surface area. Central to overcoming limitations (e.g., hydrophilicity and brittleness) are key functionalization strategies: polymer blending (e.g., with zein and PVA), chemical cross-linking, and incorporation of bioactive agents (antimicrobials, antioxidants, and pH-responsive systems). These modifications yield active/intelligent nanofiber films demonstrably effective in extending shelf life across diverse foods (meat, dairy, and soy products). By transforming slaughterhouse, dairy, and leather by-products into high-value packaging, this approach exemplifies circular economy principles, simultaneously addressing plastic pollution and organic waste disposal. Challenges in moisture stability, scalability, and regulatory alignment have been examined, yet protein nanofibers represent a sustainable technological pathway to reduce fossil-fuel dependency and advance food preservation.