Sustainable lemon oil fused active packaging films for controlling Tribolium castaneum infestation in stored food commodities.

Post-harvest deterioration of stored grains continues to pose a serious challenge to food security worldwide, particularly in developing regions where storage systems are often inadequate. Losses are primarily attributed to insect infestation and microbial spoilage, which not only reduce the quantity of available food but also compromise its quality and safety. Conventional management practices largely depend on synthetic fumigants and petroleum-based packaging materials; however, these approaches raise concerns related to environmental persistence, human health risks, and the emergence of resistant pest populations. In this context, there is a growing need for eco-friendly and sustainable alternatives that can effectively protect stored commodities. In the present study, a biodegradable and functional packaging system was developed using polylactic acid (PLA) integrated with essential oil extracted from Citrus limon. Detailed chemical characterization of the essential oil using Gas Chromatography–Mass Spectrometry (GC–MS) revealed a complex mixture of bioactive compounds, with nineteen constituents accounting for the majority of the composition. The profile was predominantly rich in oxygenated monoterpenes, particularly α-citral and citral, which are well known for their potent antimicrobial and insecticidal properties. Bioassays demonstrated that the essential oil possesses strong fumigant toxicity against the stored grain pest Tribolium castaneum, indicating its suitability as a natural protective agent. The incorporation of this essential oil into the PLA matrix resulted in the formation of composite films with enhanced functional properties. These bioactive films exhibited improved flexibility, better barrier characteristics against moisture and gases, and increased thermal resistance compared to neat PLA. Importantly, the films demonstrated significant biological efficacy, achieving high levels of insect mortality within a short exposure period, along with notable antibacterial and antifungal activity. Additionally, the films showed considerable antioxidant potential, suggesting their role in delaying oxidative deterioration of stored products. Despite their bioactivity, the films did not adversely affect seed viability, highlighting their practical applicability. At the molecular level, interactions between PLA and the phytochemical constituents facilitated a controlled and sustained release of active compounds, thereby extending the protective effect over time. Overall, this study highlights the potential of combining biodegradable polymers with plant-derived bioactive to create advanced packaging systems that are not only environmentally benign but also functionally superior for post-harvest protection.