Sustainable carboxymethyl cellulose from ozonated empty fruit bunch for application as food coating additive

The increasing demand for sustainable food packaging has sparked interest in carboxymethyl cellulose (CMC) derived from renewable oil palm biomass. This study utilized BiOzCMC, a novel CMC synthesized from ozonated Empty Fruit Bunches (EFB) using green ozonolysis pre-treatment and carboxymethylation. Response Surface Methodology (RSM) and Fractional Factorial Design (FFD) were applied to optimize sodium hydroxide (NaOH) concentration, sodium monochloroacetate (SMCA) ratio, reaction time, and temperature. The optimised BiOzCMC (R² 98.24 %) achieved a Degree of Substitution (DS) of 1.2, 250.2 % yield, 75 % purity, and 5.05 % moisture content. Analysis was conducted using several techniques, including X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Energy-dispersive X-ray Spectroscopy (EDX), Thermogravimetric Analysis (TGA), and Particle Size Analysis (PSA). The results revealed a decrease in crystallinity (5.15 %), well-defined carboxyl peaks, a smoother morphology, higher thermal stability, and a smaller particle size (0.95 μm) compared to commercial carboxymethyl cellulose (CMCc). BiOzCMC extended the shelf life, reduced weight loss, improved mechanical properties, and suppressed microbial growth for over a month when used as an additive to coat tomatoes. These results highlight BiOzCMC as a sustainable food coating additive supporting waste valorisation.