Development and Fruit Preservation Application of Bio‐Based Polylactic Acid/Wheat Gliadin Multifunctional Synergistic Bilayer Films

ABSTRACT The promotion of degradable food packaging films contributes to alleviating the problem of white pollution and facilitating the reduction of environmental contamination. Polylactic acid (PLA) is a widely used biodegradable material, but its brittleness and single function limit its application in the field of food packaging. In this study, a bilayer film was developed based on the combination of blending and casting. The film was composed of an inner PLA layer and an outer wheat gliadin–gelatin–salicylic acid blend layer. PLA was toughened with polyethylene glycol 2000 and acetyl tributyl citrate. The toughened PLA film had a certain ultraviolet shielding function. In the outer layer, wheat gliadin, gelatin and salicylic acid could be compatible, forming a stable structure and exerting their respective properties. The problem of the high viscosity of single wheat gliadin film was improved by adding gelatin. The addition of salicylic acid as a bacteriostatic agent not only made the film have an antibacterial effect, but also greatly improved the mechanical properties of the film. This film was used in a sealed packaging preservation experiment for yellow cherry tomatoes. The results showed that the 9% salicylic acid bilayer film reduced the decay rate and weight loss rate of yellow cherry tomatoes during 15 days of storage. In the soil degradation experiment, the PLA bilayer film showed obvious structural degradation after 90 days. These results highlight the promising application potential of the prepared PLA bilayer film as a sustainable and environmentally friendly packaging alternative to extend the shelf life of fresh fruit.