Rosmarinic Acid-Loaded CaCO₃ Dual-Functional Nanoplatform-Reinforced Composites for Enhanced Food Preservation

Natural biopolymer-based food packaging films have emerged as promising eco-friendly alternatives to their synthetic plastic counterparts in extending food shelf life. However, their inadequate mechanical strength and the rapid, uncontrolled burst release of active substances severely limit their practical translation. To bridge this gap, an interfacially engineered dual-functional nanoplatform was developed. Specifically, porous CaCO₃ nanoparticles loaded with rosmarinic acid (Ra) were integrated into a novel sa-son seed gum (SSG)/carboxymethyl chitosan (CMCS) cross-linked matrix. Structural characterization via SEM, TEM, FT-IR, and XRD confirmed successful Ra encapsulation, achieving an encapsulation efficiency of 39.64 ± 0.04%─surpassing prior systems. The composite films demonstrated remarkable mechanical performance with a tensile strength of 70.56 MPa, outperforming numerous natural polymer-based packaging films. Enhanced barrier properties against water vapor, oxygen, CO₂, and UV radiation were also observed in CaCO₃@Ra-modified films compared to those of pristine SSG/CMCS matrices. The presence of Ra provided antibacterial and antioxidant capabilities, while the porous structure of CaCO₃ facilitates a controlled and sustained release of Ra in different environments. These findings suggest that CaCO₃@Ra-SC (CRSC) films may have strong potential for food packaging applications.