Researchers have developed a biodegradable active packaging film from rapeseed-processing residues that could reduce reliance on petroleum-based plastics while extending the shelf life of fresh foods. The material, described in a study published in Food Quality and Safety, combines chitosan with phenolic extracts from rapeseed cake, flowers, stems, and leaves, along with biosynthesized silver nanoparticles. This combination strengthens the film, improves its barrier properties against water, oxygen, and UV light, and imparts antioxidant and antimicrobial activity, making it a promising solution for food preservation.
The study, conducted by scientists at Dalian Polytechnic University in collaboration with INNOBIO Corporation Limited, was published on May 25, 2026, and highlights the potential of using agricultural byproducts as functional resources. Rather than discarding rapeseed residues, the team extracted bioactive compounds and used them to produce silver nanoparticles under mild conditions. These were then embedded into a chitosan matrix to form films. The resulting material showed improved mechanical properties, with tensile strength increasing from about 8.1 to 17.0 MPa and elongation at break rising from 20.7% to 31.5% compared to pure chitosan films. The water contact angle also increased from 55.7° to 87.2°, indicating lower surface wettability and better water resistance.
In addition to structural enhancements, the films demonstrated strong antioxidant activity, with the flower-based film achieving up to 89.7% scavenging in the DPPH assay and 62.3% in the ABTS assay. The rapeseed-cake film inhibited the growth of Escherichia coli and Staphylococcus aureus, showcasing its antimicrobial potential. In storage tests, the films slowed quality deterioration in cherry tomatoes and enoki mushrooms, preserving weight, ascorbic acid, and titratable acidity in tomatoes, while reducing browning and microbial growth in mushrooms.
One of the most significant findings is the film's rapid biodegradability. Soil-burial experiments showed complete degradation within 21 days, with no adverse effects on bok choy growth. This supports the development of more circular packaging systems that reduce plastic waste.
The researchers note that these films could be used as coatings, wraps, or liners for fresh produce and other foods vulnerable to dehydration, oxidation, browning, and microbial spoilage. By converting underutilized rapeseed residues into valuable packaging materials, the approach could create new revenue streams for the agricultural industry while addressing environmental concerns associated with conventional plastics.
However, the path to commercial application requires further work. Scalable manufacturing processes, cost and sensory evaluations, standardized food-contact testing, and trials under realistic transport and storage conditions are necessary. The study also acknowledges that while energy-dispersive X-ray spectroscopy (EDS) found no detectable silver on tested tomatoes, this is preliminary evidence. Future research should employ more sensitive quantitative methods like inductively coupled plasma mass spectrometry (ICP-MS) to assess potential silver migration and long-term exposure risks.
This research was supported by the Basic Scientific Research Fund of Liaoning Provincial Education Department and the China Postdoctoral Science Foundation. The full study is available under DOI: 10.1093/fqsafe/fyag032.
