Introduction.

Blackberries are highly perishable fruits due to their soft skin and susceptibility to fungal diseases, such as gray mold caused by Botrytis cinerea. Ozone is a gas that can extend the shelf life and protect the fruit from the growth of B. cinerea. Objective. To evaluate the effect of gaseous ozone application on the physicochemical characteristics and postharvest quality parameters of fresh blackberries during storage. Materials and methods. This study was carried out at the National Center for Food Science and Technology of the Universidad de Costa Rica in 216. Blackberries (Rubus adenotrichos) of the ''Vino con espinas rojas'' variety were used. The fruits were inoculated with B. cinerea and treated with gaseous ozone at a range of 50-200 µg L-1 for 150 min once a day over 0, 2, 4, 7, and 10 days of storage at 2 °C. Additionally, a control treatment (without ozone) was applied. Various physicochemical characteristics (color, total soluble solids, titratable acidity, and hardness) and postharvest quality parameters (percentage of damaged fruit and fruit infected with B. cinerea) were evaluated. Results. Storage time significantly affected (p < 0.05) all the parameters analyzed, regardless of ozone application. No effect of ozone on the physicochemical parameters was observed. However, ozone treatment influenced the percentage of damaged fruit (p = 0.0067) and fruit affected by B. cinerea (p < 0.0001). After 10 days, ozone-treated fruits showed a lower percentage of fruit affected by B. cinerea (78.95 ± 1.08 %) compared to untreated samples (96.07 ± 2.19 %). Conclusion. Ozone application could be an effective method for maintaining blackberry quality, extending storage time, and improving resistance to fungal deterioration.