Fine fibrillation and TiO₂-carboxymethyl starch coating for plastic-free high-barrier antibacterial preservation...

Microbial spoilage, physiological aging, and moisture loss are key factors limiting the shelf life of fruits and vegetables. Traditional plastic packaging accelerates decay due to its impermeability, while open storage hastens moisture loss. There is an urgent need for environmentally friendly packaging materials that can effectively extend shelf life. This study utilizes natural softwood pulp, which undergoes fibrillation, papermaking, surface modification, and calendering, to develop a biodegradable paper-based material with a beating degree of 70°SR. A TiO₂:Carboxymethyl starch (CMS) = 3:5 composite coating is applied to enhance its barrier, antibacterial, and mechanical properties. The optimized paper exhibits a water vapor permeability of 2.76 × 10^-10 g/m·s·Pa, an oxygen permeability of 4.36 × 10^-14 cm³·cm/cm²·s·Pa, and a porosity of 5.88%. The dry and wet tensile index, burst index, and tear index are 52.54 N·m/g, 12.81 N·m/g, 4.56 kPa·m²/g, and 13.57 mN·m²/g, respectively. The hydrophobic angle of the paper is 116.39°, indicating excellent water resistance. The addition of TiO₂ and chitosan imparts antibacterial properties, effectively inhibiting microbial growth. Freshness preservation experiments indicate that the coated paper significantly extends shelf life, particularly outperforming polyethylene film packaging in strawberry preservation. This study offers a promising, eco-friendly alternative to conventional plastic packaging for fresh produce.