Seagrass-Derived Cellulose/Collagen Composite Coating for Enhanced Tomato Shelf Life and Postharvest Quality

This study explored an eco-friendly coating system combining seagrass-derived cellulose fiber (SCF) from Cymodocea rotundata with marine type I collagen (MC) for tomato preservation. The SCF/MC composite was prepared through enzymatic and natural crosslinking processes and subsequently characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA). The results demonstrated that SCF/MC possessed a compact morphology, strong hydrogen bonding interactions, high crystallinity, and excellent thermal stability. When applied as a coating, SCF/MC composite significantly reduced weight loss in tomatoes, preserved firmness (>39 Units), regulated acidity, maintained moisture levels (~90%), and delayed increase in pH compared to the uncoated control. Additionally, the SCF/MC coating sustained ascorbic acid and moderated lycopene accumulation, indicating delayed ripening. At 0.5% of SCF/MC composite, spoilage was limited to 22% versus ~80% in control samples, demonstrating a substantial reduction in decay. Antifungal assay showed strong inhibition of Aspergillus flavus, with the highest suppression of mycelial growth observed at 0.5% of SCF/MC. Overall, the SCF/MC coating effectively enhanced fungal safety and maintained the physicochemical quality of tomatoes, thereby extending shelf life while valorizing seagrass biomass as a sustainable postharvest resource.