Mesoscale collagen aggregates/dialdehyde soybean polysaccharide composite films for food packaging

Soluble soybean polysaccharide (SSPS) has emerged as a promising biodegradable material for sustainable food packaging, however, its application is restricted by inherently poor mechanical properties and high water sensitivity. Distinct from the collagen molecular films commonly reported in the literature, the present work introduces mesoscale collagen aggregates (CAs) as structural building blocks for the composite film. Herein, a novel bio-composite film is fabricated by incorporating CAs into a dialdehyde-modified SSPS (DS) matrix, wherein Schiff base chemical crosslinking and hydrogen bond physical interactions are formed between the two components, indicating the formation of an interconnected network. Comprehensive characterization demonstrates that the collagen aggregates/dialdehyde soybean polysaccharide composite film (CAs/DS) exhibits significantly enhanced performance compared with pristine SSPS film (SSPS-F), including a 185% increase in tensile strength, an 80% reduction in water solubility, and substantial decreases in water vapor permeability (by 31.37%) and oxygen permeability (by 31.67%). The material extended the edible shelf life of blueberries/chicken by approximately 2 days under ambient conditions (25 ± 2 °C, 55 ± 5% RH) and exhibited favorable soil degradation performance based on mass loss measurements. This work offers a strategy for designing high-performance, eco-friendly materials by integrating renewable polysaccharides with mesoscale structural proteins for food preservation applications.