HOT WATER TREATMENT MAINTAINS POSTHARVEST QUALITY OF 'KARAJ' PERSIMMON FRUIT DURING COLD STORAGE

There is not enough information about effects of hot water treatments on astringent type persimmons. Therefore in this study, the ‘Karaj’ astringent type persimmon was harvested at mature stage and treated with hot water at 45 and 50°C for 10, 20 and 30 min, along with control fruit treated at 25°C for 20 min. Then, the fruits were stored at 1°C for 4 months and selected fruit traits were monitored monthly. Results showed that colour properties (a*, b*, L*) of fruit decreased significantly throughout storage but this decrease in color properties at hot water treatment of 50°C for 20 and 30 min was lower than that of other applications and the highest decrease was recorded at control fruits. Disease incidence of control fruits increased significantly during storage, whereas in hot water treated fruits no noticeable disease symptom was recorded during the experiment. Following hot water treatments, no detectable browning disorder was observed on the fruits, but during storage, in fruit treated with hot water at 50°C for 20 and 30 min, in contrast with other treatments, skin-browning index increased significantly. Applied hot water treatments, in comparison to control, reduced fruit softening during storage, and among them, treated with hot water at 50°C for 20 and 30 min maintained fruit firmness better than that of other treatments. Generally, according to this study, hot water treatments of 45°C for 10, 20 and 30 min and 50°C for 10 min controlled fruit softening, disease incidence and colour loss of ‘Karaj’ persimmon without any negative effects on the fruit during storage, and therefore they can be recommended for increasing postharvest life of this cultivar in alternative with cold storage.