Double-layer active/intelligent film consists of lemon waste film and polyvinyl alcohol electrospun nanofibers for extending and monitoring the shelf-life of fresh beef

This study presents the development of a novel double-layer smart packaging system, which combines lemon waste powder (LWP) film enriched with betalains and polyvinyl alcohol electrospun nanofibers activated with citral (CR/PVA NFs). The red beet betalains were incorporated into the LWP-based film at varying concentrations from 0 % to 8 % g/g of LWP to serve as a colorimetric indicator. The formulation with 8 % LWP was identified as the optimal choice due to its superior color indication, water barrier, and mechanical properties. Citral-loaded PVA NFs were then electrospun onto the optimized LWP film to create the double-layer structure. The chemical and crystalline structure analyses and thermal property evaluations confirmed the successful integration of the LWP film with the citral-loaded PVA NFs. Morphological studies demonstrated the smooth surface of the film and the uniform fibrillar structure of the citral-loaded PVA NFs with an average fiber diameter of 341.58 ± 62.44 nm. The double-layer film showed inhibition activity against two food-borne pathogenic bacteria (Staphylococcus aureus and Escherichia coli) with inhibition zones of 11 and 12 mm, respectively. Furthermore, the packaging system effectively extended the shelf life of fresh beef while monitoring its freshness, successfully detecting spoilage and regulating microbial growth, pH levels, total volatile basic nitrogen, and oxidation changes during storage.