In a move toward more sustainable food packaging, a research team has developed a biodegradable film from rapeseed processing residues that actively preserves fresh produce. The material, which combines chitosan with phenolic extracts from rapeseed cake, flowers, stems, and leaves, along with biosynthesized silver nanoparticles, offers enhanced strength, water resistance, and antioxidant and antimicrobial properties. This innovation addresses the environmental burden of conventional plastics while adding value to agricultural byproducts.
The study, published in Food Quality and Safety on May 25, 2026, was conducted by researchers from Dalian Polytechnic University and INNOBIO Corporation Limited. They extracted bioactive compounds from Brassica napus L. residues and used them to synthesize silver nanoparticles, which were then incorporated into a chitosan matrix. The resulting composite films were tested for their physical, chemical, and biological properties, as well as their ability to preserve cherry tomatoes and enoki mushrooms.
Compared to pure chitosan films, the composite films showed significant improvements. Tensile strength increased from 8.1 to 17.0 MPa, elongation at break rose from 20.7% to 31.5%, and the water contact angle increased from 55.7° to 87.2°, indicating better water resistance. The films also blocked UV light and exhibited strong antioxidant activity, with the flower-based film achieving 89.7% DPPH scavenging and 62.3% ABTS scavenging. The rapeseed cake-based film inhibited Escherichia coli and Staphylococcus aureus.
In storage tests, cherry tomatoes coated with the film retained more weight, ascorbic acid, and titratable acidity, while enoki mushrooms showed less browning and microbial deterioration. The films also degraded completely in soil within 21 days without affecting bok choy growth, demonstrating their environmental friendliness.
The researchers emphasize that this approach turns waste into a functional resource. 'Crop residues can do more than replace part of a packaging material: their natural chemistry can help the package actively protect food,' the authors stated. The films could be used as coatings, wraps, or liners for fresh produce, reducing reliance on persistent plastics and creating new value streams for rapeseed-processing residues.
However, commercial application faces challenges. Scaling up manufacturing, conducting cost and sensory assessments, and performing standardized food-contact testing are necessary. While EDS found no detectable silver on tested tomatoes, the study considers this preliminary. Future work should employ quantitative methods like ICP-MS and evaluate long-term exposure and degradation in diverse environments.
The study was supported by the Basic Scientific Research Fund of Liaoning Provincial Education Department and the China Postdoctoral Science Foundation. The full paper is available at https://doi.org/10.1093/fqsafe/fyag032.
