Effect of lipid addition on the physiochemical, structural, and photoactive antibacterial properties of cornstarch-chlorophyllin composite film

Abstract

The study aimed to prepare cornstarch-chlorophyllin (CS-Chl) composite films with coconut oil (CO), oregano essential oil (OEO), and beeswax (BW) at percentages of 0.5 %, 1.0 % and 1.5 %, to address the key limitation of the hydrophilic nature of the CS-Chl matrix, and the physiochemical, structural and photoactive antibacterial properties of the films were evaluated. The moisture content, water solubility, swelling ability, and water vapor permeability were significantly reduced in all CO_x/OEO_x/BW_x samples, with average values of 12.58 %, 15.41 %, 29.30 %, and 1.78 × 10⁻¹⁰ gm⁻¹s⁻¹Pa⁻¹, respectively. Regarding mechanical properties, the tensile strength (TS) in CO_x and BW_x films increased, while the elongation at break (EAB) decreased with the increasing CO and BW percentages. However, in OEO_x films, initially, the TS was increased, then reduced with the rising OEO percentage. The FTIR spectrum indicated better CO, OEO, and BW molecule integration with the CS matrix and Chl molecules. XRD spectrum showed low crystallinity, while SEM images visualized rough surfaces with heterogenous structures in the cross-section. Despite the similarity in reactive oxygen species (ROS) production in CO_x/OEO_x/BW_x films, shrimp wrapped in these films were safe for consumption after 5 days. The results highlighted the impact of lipid concentration and ROS generation, confirming that CS-Chl films with CO_x/OEO_x/BW_x offer enhanced antibacterial properties compared to polyethylene (PE) films, positioning them as innovative solutions for food packaging in practical applications.