APPLICATIONS

New Chitosan-based film with microalgae oil shows promise for extending strawberry shelf life

China, 14 August 2025 |

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A team of researchers from Xi’an University of Technology, in China, has developed an innovative biodegradable packaging film that could significantly improve the shelf life of fresh produce. The study, published in Food Research International, reports that incorporating oil from the marine microalga Schizochytrium limacinum into chitosan-based films enhances their antioxidant, antimicrobial, and moisture-barrier properties.

The scientists used a Pickering emulsion-a technique where solid particles stablished oil droplets in water-with soy protein isolate to evenly disperse the microalgal oil in the chitosan matrix. The oil is rich in polyunsaturated fatty acids such as DHA and EPA, as well as antioxidant carotenoids. Laboratory tests showed that adding 10% oil increased the film’s water contact angle to 91.79º (indicating improved hydrophobicity) and reduced water vapour permeability. The film also effectively blocked UV light in the 200-380 nm range and reached a DPPH radical scavenging activity of 89.67%, compared with 7.51% for chitosan alone.

Antibacterial assays demonstrated growth inhibition rates up to 95.19% for Staphylococcus aureus and 88.19% for Escherichia coli. In storage trials at room temperature, strawberries wrapped in the composite film retained higher firmness (2.92N), had 20.34% less weight loss, and maintained titratable acidity better than control fruit after seven days. Visual inspection confirmed reduced mould growth and better colour preservation.

The authors conclude that the Staphylococcus aureus chitosan film has strong potential as an eco-friendly active packaging material for post-harvest fruit preservation. However, they recommend further studies to assess possible migration of active compounds and to confirm long-term safety for direct food contact.

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