Effect of different CO2 deastringency application timing on fruit quality attributes and physiological disorders in cold-stored ‘sangjudungsi’ persimmon fruit

The effects of different application timing of CO₂ deastringency treatment on fruit quality attributes and physiological disorders of ‘Sangjudungsi’ persimmon fruit during cold storage were evaluated. Treatment with an application of 95% CO₂ at harvest ensured the complete removal of astringency after one or two months of cold storage. The deastringency treatment greatly reduced flesh firmness, and early CO₂ application caused the lowest flesh firmness at the end of cold storage. The soluble solids content (SSC) was also decreased after CO₂ application, while fruit treated later with CO₂ had lowest SSC, compared with the other CO₂ application timings. Weight loss and respiration rate both increased in deastringency-treated fruit. Peel color variables, as measured using the CIELab color space, were also affected by the treatment. The changes in peel color variables were more detectable in the calyx-end regions than in the equatorial regions. Fruit treated with CO₂ one-month after harvest were observably different in peel color variables. Flesh browning was also detected in fruit treated one-month after harvest. The decrease in astringency following CO₂ treatment led to increased incidence of flesh browning and fruit softening at the end of the cold storage period. Peel blackening was also detected in early deastringency-treated fruit at the end of cold storage. This study suggested that earlier CO₂ application may decrease flesh firmness and increase the incidence and severity of physiological disorders in ‘Sangjudungsi’ persimmon fruit during cold storage.