Active starch-based film using polyvinyl alcohol and chlorogenic acid for strawberry preservation: A comparative analysis of mechanical, barrier, and antibacterial properties

The broad application of starch films has been significantly limited by their insufficient hydrophobicity and antibacterial activity. To overcome these challenges, this study developed a new starch film by incorporating polyvinyl alcohol (PVA) and chlorogenic acid. The study explored the impact of PVA polymerization on the physical and functional characteristics of the resulting films, with particular emphasis on enhancing antimicrobial functionality by incorporating chlorogenic acid. Scanning electron microscopy (SEM) and rheological tests demonstrated the excellent compatibility and exceptional film-forming performance. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses validated the presence of intermolecular entanglements and hydrogen bonding within the films. Incorporating PVA with a polymerization degree of 2400 resulted in a contact angle (CA) of 79.81 ± 1.74°, a water absorption capacity (WAC) of 10.29 ± 0.71 %, and a water vapor permeability (WVP) of (0.44 ± 0.11) × 10^-11 g × m^-1 × s^-1 × Pa^-1. Notably, the SCP 2488 film exhibited superior mechanical properties, including the highest Young's modulus of 71.29 MPa, tensile strength of 11.77 MPa, and elongation at break of 106.75 %. Additionally, such a modified film displayed enhanced UV-blocking performance and antibacterial efficacy. Consequently, the SCP 2488 film showed great potential for maintaining the freshness and quality of strawberries.