Development of corn straw lignin-based cling films for enhanced preservation of strawberries

Biodegradable cling film is an environmentally friendly alternative to traditional plastics which still requires the addition of preservatives to improve its ability to retain freshness. Lignin, which is a natural product with both safety and antioxidant effects, has become a potential preservative. In this study, lignin was extracted from pine and corn straw by deep eutectic solvent. The lignin yield was 40.54 % and 60.60 %, respectively. A series of CS/LNPs cling films were prepared by lignin nanoparticles as the main freshness preservation and chitosan (CS) as substrates. The film with 5 % lignin nanoparticles (CS/LNPs-5) demonstrated an 89.10 % DPPH radical scavenging rate, indicating superior antioxidant capacity. Moreover, the CS/LNPs-5 films showed good UV shielding ability, mechanical properties, and hydrophobicity. Remarkably, CS/LNPs-5 was applied to preserve perishable strawberries, which extended their freshness for up to 9 days. In this study, lignin nanoparticles were successfully used to prepare cling film with high antioxidant properties, which provides a new approach for lignin in food packaging.