Development and application of Mentha piperita extract-based nanocomposite films in gelatin and sodium alginate–xanthan gum matrix for fish meat quality and preservation

This study reports the development of nanocomposite films incorporating Mentha piperita (peppermint) extract (MPE) into a gelatin and sodium alginate–xanthan gum biopolymer matrix to improve the refrigerated preservation of fish meat (4 ± 1°C). The films were characterized for structural properties, antioxidant and antimicrobial activities, and evaluated for their effectiveness in maintaining fish quality during storage. Field Emission Scanning Electron Microscopy (FESEM) confirmed compact, smooth, and uniformly dispersed extract particles that enhanced film integrity. The films exhibited strong antioxidant and antimicrobial activity, as evidenced by microbiological and physicochemical analyses. Sensory evaluation demonstrated significantly higher odor (8.5 ± 0.3), texture (8.2 ± 0.4), and the overall acceptability scores (8.6 ± 0.2) in treated fish compared to controls (6.1 ± 0.5, 6.3 ± 0.4, and 6.0 ± 0.6, respectively) after 12 days of storage. Microbiological analysis showed reduction in total viable counts (from 7.9 ± 0.2 to 4.3 ± 0.1 log CFU/g) and psychrotrophic bacteria (from 7.2 ± 0.3 to 4.0 ± 0.2 log CFU/g). Lipid oxidation, measured as thiobarbituric acid reactive substances (TBARS), was also lower in treated samples (0.94 ± 0.05 mg malondialdehyde [MDA]/kg), compared to controls (2.35 ± 0.08 mg MDA/kg). These findings demonstrate that MPE-based nanocomposite films are effective biodegradable packaging materials that can enhance sensory quality, inhibit microbial growth, and extend the shelf life of fish meat.