Maryam Beigomi, Mohammad Amin Mashhadi, Moharram Valizadeh, Farzaneh Farajian Mashhadi
This research investigated the feasibility of utilizing Hibiscus sabdariffa sepal mucilage (HSSM) as a novel biopolymer matrix in combination with carboxymethyl cellulose (1%, w/w) and varying glycerol content (10%, 15% and 20%, w/w) for the development of biodegradable films. The microstructural, thermal, mechanical, and physical properties, as well as the antioxidant and antimicrobial potential, of the resulting biodegradable films were evaluated. Results indicated that increasing glycerol content led to significant increases in film thickness, moisture content, solubility, water vapor permeability, and elongation at break (EB%), confirming its plasticizing effect within the HSSM-based matrix. Conversely, tensile strength, melting temperature, and glass transition temperature (Tg) decreased significantly with increasing glycerol content. Color analysis showed that the films remained transparent, with slight greenish or reddish coloration at higher glycerol levels. Scanning electron microscopy revealed that glycerol-containing films exhibited a more uniform and homogeneous morphology without visible cavities or fractures compared to films without glycerol. Furthermore, the unplasticized HSSM film demonstrated notable antioxidant activity, and the optimized HSSM-CMC film (10% glycerol) exhibited significant antimicrobial activity against Staphylococcus aureus and Bacillus cereus. These findings suggest that HSSM-CMC films have strong potential for active food packaging applications. Overall, combining HSSM with carboxymethyl cellulose led to the development of biodegradable films with improved structural integrity and desirable functional attributes.