Biomass-based bilayer film derived from corn starch and polylactic acid for banana packaging

Biomass-based materials have the potential to protect fruits and meet environmental requirements when applied to fruit packaging. However, their mechanical properties and barrier properties are insufficient compared with plastic packaging, which limits their application. In this study, a high-barrier bilayer film derived from corn starch (CS) and polylactic acid (PLA) was applied for banana pulp preservation. Results indicated that the bilayer film exhibited good barrier performance. The water vapor permeability and oxygen permeability of bilayer films were lower than that of pure CS or PLA film. In the 3 days preservation experiment, the weight loss of banana pulp packaged by CS/PLA bilayer film at ratio of 15:45 was the lowest (1.36%), while the pH and firmness of banana pulp packaged by this ratio bilayer film were the largest, reflecting that the bilayer film could effectively delay the oxidation and deterioration of banana pulp. Moreover, the CS/PLA bilayer film was analyzed by scanning electron microscopy and Fourier transform infrared spectrometry, which also evidenced that PLA could provide better mechanical strength and barrier properties, and CS had hydrophilic and biodegradable potential. In conclusion, it is feasible to combine CS and PLA to prepare the bilayer films. The study is beneficial to promote the development and application of eco-friendly bio-based packaging film.