Biocompatible carboxymethyl cellulose-potato starch film with biosynthesized tellurium nanoparticles and undecanoic acid for enhanced antimicrobial protection in post-harvest tomato preservation.

Abstract

Preserving the post-harvest quality of fruits by minimizing microbial contamination is essential for ensuring food safety. In this study, a novel composite film was developed using carboxymethyl cellulose (CMC) and potato starch (PS), reinforced with tellurium nanoparticles (BP-Te NPs, 93.66 ± 24.43 nm) synthesized from banana peel extract and supplemented with undecanoic acid (UDA). BP-Te NPs demonstrated potent antibacterial and antioxidant activities but only moderate antifungal efficacy. To overcome this limitation, UDA was co-incorporated with BP-Te NPs into the CMC-PS matrix. The resulting CMC-PS-UDA-BP-Te NPs film exhibited excellent UV-blocking and water vapor barrier properties (WVTR: 374.20 ± 2.80 g·mm·m-2·day-1), along with favorable mechanical characteristics, including tensile strength (14.85 ± 0.32 MPa), elongation at break (12.45 ± 3.85 %), and rapid water solubility (>90 % within 6 min). The nanocomposite film also demonstrated strong antibacterial and antifungal activity, maintained >80 % cell viability in NIH3T3 cells at concentrations up to 50 μg/mL, and showed no hemolytic activity up to 1000 μg/mL. Application of the film on cherry tomatoes effectively reduced microbial proliferation, limited weight loss, and preserved key quality parameters such as pH, total soluble solids, and phenolic content over a 7-day period. These findings suggest that the CMC-PS-UDA-BP-Te NPs composite film is a promising and sustainable alternative for post-harvest preservation of tomatoes and potentially other food products.