Evaluation of Antimicrobial and Antioxidant Properties of Active Starch-Based Food Packaging Films Enriched with Citric Acid

Background and Objective: Growing environmental concerns regarding synthetic packaging materials have accelerated interest in biodegradable and functional food packaging alternatives. This study aimed to formulate and characterize starch-based biodegradable food packaging films enriched with different concentrations of citric acid to enhance their antioxidant and antimicrobial properties. Materials and Methods: Starch-based films were prepared using starch, polyvinyl alcohol (PVA), kaolin, citric acid, and glycerol as a plasticizer. Kaolin clay was incorporated as a reinforcing agent, while citric acid was used as a functional additive at concentrations of 0, 2.5, 5, and 7.5%. Antioxidant activity was evaluated using the 2,2 -azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay, whereas antimicrobial activity was determined by the agar well diffusion method against Escherichia coli and Staphylococcus aureus. Statistical analysis was performed using BMDP 2R software (version 7.0) for stepwise multiple regression, with results expressed as mean±replicate measurements (n = 3) and significance set at p<0.05. Results: The findings demonstrated a positive correlation between citric acid concentration and the bioactivity of the films. The film containing 7.5% citric acid exhibited the highest ABTS radical scavenging activity, approaching the antioxidant potential of the vitamin C control. Similarly, the same formulation showed the largest inhibition zones against both test microorganisms, indicating enhanced antimicrobial efficacy. These results suggest that citric acid contributes not only as a natural cross-linking agent b ut also as a bioactive enhancer in starch-based films. Conclusion: Citric acid-enriched starch-based films exhibited promising antioxidant and antimicrobial properties, highlighting their potential as environmentally friendly food packaging materials. The developed films may contribute to improved food safety and shelf-life extension, offering a sustainable alternative to conventional synthetic packaging in the food industry.