Cold plasma-modified goat milk casein/Chinese yam polysaccharide/chitosan composite films: Structural, functional, and preservative properties for fresh pork.

A biodegradable edible film based on cold plasma-modified goat milk casein, Chinese yam polysaccharide, and chitosan was developed. The effects of different casein-to-polysaccharide ratios on the functional and structural properties of the films were systematically investigated. This study aimed to optimize the formulation, elucidate the mechanism of structural changes, extend the shelf life of pork, and provide a natural bio-based active packaging solution. The results revealed that the film with a 1:2 ratio had a hydrophobic surface and exhibited significantly superior barrier properties against moisture, oxygen, carbon dioxide, and oil (P < 0.05). Its tensile strength and elongation at break reached 21.65 MPa and 52.33%, respectively. At this ratio, the film promoted hydrogen bonds and electrostatic interactions and enhanced cross-linking density, resulting in a dense and uniform network structure. Moreover, the film extended pork shelf life by 2-4 days. Therefore, this film shows great potential as a food packaging material.