Development of a chitosan-based edible coating enhanced with citric and ascorbic acids for enhancing postharvest quality and microbiological stability of tomato (Solanum lycopersicum)

This study examines the effectiveness of a chitosan-based edible coating, enhanced with citric and ascorbic acids, in improving the microbiological stability and quality of tomatoes ( Solanum lycopersicum ). In vitro experiments demonstrated that chitosan alone exhibited inhibition zones of 0.65 cm for E. coli and 1 cm for S. aureus , whereas the complete formulation showed a synergistic effect, achieving 100% inhibition of mycelial growth in fungi of the genus Alternaria . Furthermore, the antioxidant capacity (DPPH) of the chitosan solution increased from an initial 30% to an average of 92% upon incorporating the organic acids. In fruit trials, the treated tomatoes maintained a significantly higher antioxidant capacity, reaching 69% DPPH inhibition at 21 days, compared to 64% in the control group. In targeted inoculation tests, the edible coating (EC) was effective in reducing the S. aureus load by 2 log units after seven days of refrigerated storage, while the population in the control group increased by 1 log unit. These findings confirm that the proposed formulation is an effective technological alternative for enhancing microbiological safety and preserving the antioxidant quality of tomatoes during postharvest.