Modeling and optimization of the effect of preharvest carvacrol concentration in chitosan–carvacrol composite treatment on the postharvest quality of strawberry during storage using response surface methodology (RSM)

Strawberry ( Fragaria × ananassa Duch) possesses a limited shelf life due to its high respiration rate and significant susceptibility to postharvest quality deterioration. In the present study, the interactive effects of a preharvest chitosan–carvacrol composite formulation (1.5% chitosan enriched with 0–0.6% carvacrol) on the postharvest quality of 'Paros' strawberries during 30 days of storage were investigated and optimized using response surface methodology (RSM). The evaluated parameters included total phenolic content, total flavonoid content, vitamin C, soluble solids content, tissue firmness, and weight loss. The results demonstrated that the preharvest-applied chitosan–carvacrol treatment significantly reduced weight loss and preserved bioactive compounds and tissue firmness compared to the untreated control (distilled water). The developed regression models exhibited a satisfactory fit and high predictive capability (R² > 0.89). Optimal conditions were determined to be 0.55% carvacrol and approximately 20 days of storage, which provided the highest quality stability. The findings of this study suggest that the preharvest-applied chitosan–carvacrol treatment could serve as a natural and effective strategy for extending the shelf life and preserving the nutritional quality of strawberries throughout the postharvest supply chain, potentially through the modulation of oxidative processes and the maintenance of tissue structure.