Silane-modified starch reinforced chitosan/lignosulfonate composite film for grape preservation

To address environmental and food safety challenges from plastic food packaging films, developing multifunctional biobased films is critical. However, the application of starch-based materials is limited by inherently poor hydrophobicity, inadequate film-forming capacity, and insufficient antimicrobial activity. This study fabricated a multifunctional biobased composite film (CH/SL-VTSC) by blending vinyltriethoxysilane-modified starch (VTSC) with chitosan/sodium lignosulfonate (CH/SL), and investigated the effects of VTSC content on the properties of CH/SL-VTSCs. Benefiting from the formation of hydrogen bonds and Si-O-C covalent bonds between VTSC and CH/SL as well as surface roughening, the mechanical properties and hydrophobicity of CH/SL-VTSCs were significantly improved. Compared with CH/SL, CH/SL-VTSC2.5 exhibited high WCA (122.7°), excellent WVTR (148.34 g/(m²·d)) and outstanding oxygen permeability (1.11 g/(m²·d)). Moreover, the presence of sodium lignosulfonate endowed films with outstanding UV-blocking performance (∼99 %), and synergized with chitosan to confer potent antibacterial activity against E. coli. Grape preservation experiments demonstrated that CH/SL-VTSC2.5 effectively maintained fruit hardness, color, and acidity during 12-day storage, exhibiting preservation performance approaching that of commercial polyethylene cling film. With these advantageous features, our developed CH/SL-VTSC2.5 exhibits significant potential for food packaging applications.