A novel ε-polylysine-reinforced pullulan/curdlan-active film for an efficient preservation of fresh-cut fruit and vegetable.

Abstract

In this study, a novel active film was developed by employing ε-polylysine (ε-PL) as a filler in pullulan/curdlan (P/CD) composite film (P/CD/ε-PL). The results showed that the structure of P/CD films was more uniform and denser compared to pullulan films, due to the good compatibility and intermolecular interaction between them. Among P/CD films, P/CD 6:1 film showed improved hydrophobicity, mechanical and barrier properties, and thermal stability, thereby selecting it for further use. Thereafter, the addition of ε-PL further enhanced the structural and physicochemical properties of prepared P/CD/ε-PL composite films, especially for P/CD/2.5%ε-PL composite film. It exhibited improved ultraviolet barrier (about 80% at 200-400 nm), antibacterial activity (>90% against Staphylococcus aureus and Escherichia coli), and anti-fog properties (clearly visible and transparent background). Furthermore, P/CD/2.5%ε-PL composite film exerted its preservation effect on fresh-cut peppers and kiwis during storage, delaying the softening, consumption of soluble solids, and deterioration. Therefore, the developed P/CD/2.5%ε-PL composite film provided promising applications of active packing film. Practical Application: Fresh-cut fruits and vegetables are prone to deteriorate during storage, and active packaging films play a crucial role in retaining their quality. This study was conducted to prepare a composite film by blending pullulan, curdlan, and ε-PL and explore its structural, physicochemical, and functional properties, further verifying the preservation effect on fresh-cut peppers and kiwis. Compared to polyethylene film, the P/CD/2.5%ε-PL composite film delayed the softening, consumption of soluble solids, and deterioration of fresh-cut peppers and kiwis during storage. It provides a new perspective on the preservation of fresh-cut fruits and vegetables.