Biodegradable chitin nanocrystal/zein double-layer film with enhanced barrier properties for sustainable food...

Development of biodegradable packaging films with enhanced barrier properties is critical for practical food preservation applications. Herein, we describe a facile electrostatic deposition strategy for manufacturing a high-performance packaging film from renewable resources (for example, chitin and zein). This process employs deacetylated chitin nanocrystals (D-ChNCs) as film substrates, synergized with a hydrophobic zein layer through electrostatic interactions to enhance the barrier properties of deacetylated chitin nanocrystal film (D-ChNC-F). Compared with the neat D-ChNC-F, the film deposited with a zein layer shows a significantly elevated water contact angle (101^o) and UV blocking efficiency (99%), while also demonstrating a lower water vapor permeability (3.9 ± 0.5 × 10^-10 g m^-1 s^-1 Pa^-1) and oxygen transmission rate (769.4 ± 47.4 cm³/m² d bar). Besides, the resulting film exhibits adequate biocompatibility with GES-1 cells, with a cell viability >98%, and it achieves nearly complete degradation in soil within 75 days. Due to the improved barrier properties, the fabricated film shows enhanced fresh-keeping efficacy in preventing color degradation, lipid oxidation, and autolytic/microbial spoilage of fresh beef. This electrostatic deposition strategy provides a promising platform for the production of high-performance, biodegradable, and sustainable natural packaging films, thereby offering a safeguard measure for food safety and quality.