Zein/gelatin-starch bilayer films: a green approach for yellow cherry tomato preservation

The extensive use of petroleum-based plastics in packaging films has led to significant ecological and environmental issues, highlighting the urgent need to develop sustainable green alternative materials. In this study, a bilayer film composed of gelatin, cassava starch, and organically modified montmorillonite as the inner layer, with hydrophobic zein forming the outer layer, was fabricated. The bilayer structure was found to form a stable interface via hydrogen bonding and electrostatic interactions. The introduction of the outer layer was observed to significantly enhance the mechanical properties, hydrophobicity, and barrier performance of the film. In particular, when the volume ratio of the inner to outer layers was 10:3, the bilayer film exhibited optimal performance. The film was applied in a preservation experiment involving yellow cherry tomatoes. The results indicated that the bilayer film effectively delayed the deterioration of the physical and chemical properties of yellow cherry tomatoes, extending their shelf life by over 6 days. Its preservation effect was superior to that of PE film. Therefore, the prepared bilayer film demonstrates potential for application in fruit and vegetable preservation packaging, providing a novel approach for the development of green, biodegradable food packaging materials.