Effects of the antimicrobial peptide Ctx(Ile21)-Ha on the physicochemical and biochemical quality of organic strawberries during post-harvest storage

Strawberries are highly perishable fruits, and effective postharvest strategies are required to maintain their quality and extend shelf life. In this way, this study evaluated the application of the antimicrobial peptide Ctx(Ile 21 )-Ha on the physicochemical and physiological quality of strawberries during storage. Physicochemical parameters such as pH, titratable acidity, soluble solids, ‘ratio’, texture, and respiratory rate were carried out employing Oso Grande type strawberries embedded in an aqueous solution containing different concentrations of the Ctx(Ile 21 )-Ha. Treatments with the peptide did not significantly affect phenolic compounds or total soluble solids, indicating that the molecule preserved the intrinsic chemical composition of the fruit. However, storage time significantly influenced fruit quality, with increases in pH (3.6–4.1) and reductions in titratable acidity (0.2–0.1 g citric acid 100 g ⁻¹) and ascorbic acid (0.9–0.6 g/mL), consistent with the natural ripening process. Notably, fruit texture was maintained throughout storage, reaching higher firmness values at the final stage (5.5 N), suggesting reduced softening. Also, a significant interaction between peptide concentration and storage time was observed for soluble solids and SS/TA ratio, while soluble solids remained relatively stable, the SS/TA ratio increased at specific time points in treated samples, indicating modulation of flavor-related attributes. However, CO 2 respiration rate showed high variability and, after data screening, no consistent effect of the peptide on respiration could be confirmed. Therefore, changes in respiration could be mainly associated with storage time rather than treatment. Overall, Ctx(Ile 21 )-Ha contributed to maintaining strawberry quality by preserving firmness and modulating physiological responses during storage. These findings demonstrate the antimicrobial peptide potential as a postharvest preservative treatment to delay senescence and improve perishable fruits’ shelf life.