Valorization of Corn Bran-derived Carbohydrate Polymers for Developing Biodegradable Packaging Films

Abstract

This study aims to develop biobased composite films using hemicellulose (HB), methylcellulose (MC), and carboxymethyl cellulose (CMC) combined with natural additives, including high methoxy pectin (HMP), selected proteins (whey, casein, soy, and pea), and glycerol. Results showed that integrating these components significantly improved the physical qualities, peelability, foldability, and transparency, particularly in HB/CMC-based films. Mechanical properties of the films, i.e., elongation at break, tensile stress, elastic modulus, and toughness, were also enhanced by incorporating these additives. Among the combinations studied, the HB/CMC-based films with HMP, sodium caseinate (NaCas) or pea protein isolate (PPI), and glycerol (G) films exhibited the highest elongation at a break of 139%. Supplementing additives to HB, MC, or CMC-based films improved thermal stability, supported by thermogravimetry. Combining HMP/NaCas/G to HB/CMC resulted in films with the highest peak temperature (276° C). Additionally, integrating NaCas into the films also reduced oxygen and water vapor permeabilities by up to 25% and 11%, respectively, compared to their controls. Fourier Transform Infrared spectroscopy (FTIR) revealed an additive relationship between HB and MC or CMC composite films relative to their singular spectra. SEM showed a smooth compact structure, indicating a homogeneous blending amongst all components. This work demonstrated a viable solution for developing environmentally friendly bio-packaging materials based on HB extracted from corn bran, a plentiful low-value by-product of the biofuel industry’s corn kernel dry milling process combined with other agricultural-derived biomass, such as pectin, proteins, and glycerol.