Performance enhancement of chitosan/hydroxypropyl starch blend casing by cinnamaldehyde cross-linking and its application in sausage preservation.

Traditional collagen casings struggle to meet the preservation requirements for high-quality sausages due to their limited functionality and inadequate performance in high-humidity environments. This study aimed to develop a novel casing that combines excellent physical properties with biological activity. By blending chitosan (CS) with hydroxypropyl starch (HPS) and innovatively incorporating natural cinnamaldehyde (CA) as a crosslinking agent, a CS/HPS-CA blend casing was successfully prepared. The optimal formulation was determined to be CS:HPS = 7:3 with a CA addition of 12%. Characterization results confirmed an effective Schiff base reaction between CA and CS, leading to the formation of a denser structure. This resulted in a casing with a tensile strength of 26.8 MPa, a water vapor permeability reduced to 3.64 × 10-7 g·m·m-2·h-1·Pa-1, and significantly enhanced thermal stability and hydrophobicity. Application tests demonstrated that this casing significantly inhibited microbial growth in sausages, effectively delayed quality deterioration, and extended the shelf life beyond that of traditional casings, reaching over 60 days. This research provides a new strategy for developing high-performance and multifunctional polysaccharide-based casings.