Preparation and characterization of edible films from gelatin and hydroxypropyl methyl cellulose/sodium carboxymethyl cellulose

Abstract

This study investigates the enhancement of gelatin (GEL) films using hydroxypropyl methylcellulose (HPMC) and carboxymethyl cellulose (CMC) for edible film packaging applications. Although GEL is biocompatible and cost-effective, its limited mechanical strength presents significant challenges for practical applications. The findings indicate that CMC effectively increases tensile strength (TS), while HPMC improves elongation at break (EAB) and hydrophilicity. Notably, the composite modification with HPMC and CMC proves to be more effective than individual modifications. The optimal HPMC/CMC ratio of 3:7 resulted in blend films that exhibited the highest TS and lowest water vapor permeability (WVP). Fourier transform infrared (FTIR) analysis revealed enhanced hydrogen bonding between the polymers, while scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) confirmed a more uniform structure with improved thermal stability in the blend films. These results suggest that optimizing the HPMC/CMC ratio in gelatin-based films can significantly enhance their mechanical, barrier, and thermal properties, providing new possibilities for their application as food packaging materials.