Recent progress in hygroscopicity improvement strategies of protein-based films for edible food packaging

Background

Packaging is a crucial step in ensuring food safety, maintaining food quality and reducing food waste. Petroleum-based materials dominate food packaging due to their excellent barrier properties, mechanical strength, and low cost. However, their persistence in the environment, potential for chemical migration into food, and reliance on non-renewable resources raise significant environmental and safety concerns. This highlights the urgent need for sustainable alternatives. As a biodegradable and biocompatible alternative, protein-based films (PBFs) are considered ideal for sustainable packaging. Nevertheless, the abundance of hydrophilic groups within protein molecules confers high hygroscopicity to PBFs, which is a key limitation to their practical application.

Scope and approach

This review systematically examines the film forming properties of plant and animal derived PBFs and elucidates their hygroscopic mechanisms from the perspectives of wettability, free volume, swelling behavior, and hydrogen bonding networks. Two key modification strategies are specifically addressed: multilayer and composite films. Furthermore, the application potential of PBFs in food preservation is critically assessed, highlighting their practical value. Finally, bottlenecks hindering industrialization and the prospects for PBFs are also discussed.

Key findings and conclusions

Bionic surface —drawing inspiration from natural models— has emerged as a promising frontier for significantly enhancing the hydrophobicity and moisture barrier properties of PBFs, achieving increased water contact angle. Despite these significant advancements, critical challenges persist that impede broader practical application. These include ensuring multilayer interfacial stability, refining structural design, and controlling active component release kinetics.