Abstract
To establish a stable production method for soft ripe ‘Saijo’ persimmon (Diospyros kaki Thunb.) fruit, the fruit were treated with fatty acids or ethylene after several weeks’ storage at 0°C. Softening of the fruit first occurred in the vicinity of the calyx. Partial softening was observed at 23, 16 and 3 days after the beginning of treatment in the control, and those treated with 100 μL linolenic acid and 100 ppm ethylene for 48 hours, respectively. With each treatment, the fruit soft-ripened (complete removal of astringency) 3 days after partial softening. All the ethylene treated fruit soft-ripened at one time 6 days after the beginning of treatment. Ethylene treatment was found to be the fastest and the most reliable method for producing soft ripe ‘Saijo’. Coloration in the ethylene-treated fruit was improved and fruit firmness decreased linearly. Soluble tannin concentration began to decrease 3 days after the beginning of treatment and astringency was removed completely on the sixth day. Fruit that was stored at 0°C for 2 to 8 weeks and then treated with ethylene soft-ripened 6 days after beginning of treatment. When fruit were stored for longer than 4 weeks at 0°C and then treated with ethylene, cracking occurred in the fruit during the course of soft-ripening.
