Preparation and Characterization of Poly(L-lactic acid) Coating Film for Strawberry Packaging

Antibacterial poly(L-lactic acid)-poly(ethylene glycol)-poly(L-lactic acid)/poly(ethylene glycol) (PLGL/PEG) crosslinking chitosan (CS) (PLGL/CS-PEG) coating films were prepared with PEG as the media. Microscopy and ATR-FTIR experimentally confirmed that a good interfacial binding force was formed since the presence of PEG in both layers enhanced the compatibility and hydrogen bonding effect in multilayer membranes. The tensile strength and ductility of PLLA were greatly improved with the presence of crosslinking CS. In addition, the coating film has lower CO₂ and O₂ permeability. However, a higher CO₂/O₂ perm-selective ratio of approximately 8.6 was approximately 2.7 times that of neat PLLA. Storing experiments were also carried out to determine the effects of multilayer films on sensory quality and microbial propagation in strawberries under cold storage. The results showed that strawberries maintain good sensory quality on the 10th day and that antibacterial multilayer film was effective as an antimicrobial when used in strawberry packaging.