|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1996 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1995 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1994 : ¥1,300,000 (Direct Cost : ¥1,300,000)
For the better commercialization of the Japanese persimmon fruit, SAIJO, I have established the conditions of post-storage treatment that prevent the fruit softening following the artificial removal of astringency.
1. The concentration of soluble tannin, that exhibit the taste of astringency in the fruits began to decline from the beginning of the storage at 0℃. The concentration of soluble tannin decreased to 25-50% than the original level until 30 days.
2. The hardness of whole fruit depends on the hardness of the peripheral region of the fruit at the depth of 5 mm under the skin, In a fruit, the pedicel region was harder than the top of fruit. Although a fruit was stored at 0℃ for 50 days, it kept hardness at the top region comparable with that of pre-storage fruit.
3. During the artificial removal of astringency, COィイD22ィエD2 penetrate into a fruit by diffusion and intra-fruit gas was driven out simultaneously. The speed of COィイD22ィエD2 diffusion depends on the OィイD22ィエD2 concentration.
In 10% OィイD22ィエD2 condition, when COィイD22ィエD2 concentration was lower than 40%, the speed of diffusion became slow, on the other hand, when COィイD22ィエD2 concentration was higher than 60%; the speed of COィイD22ィエD2 diffusion into a fruit was independent of the OィイD22ィエD2 concentration. COィイD22ィエD2 diffused into a fruit as found at 100% COィイD22ィエD2 condition.
4. The speed of COィイD22ィエD2 diffusion into a fruit also depended on the temperature. It proceed most quickly at 10℃ condition at the first 3 hrs (80% of total diffusion volume). COィイD22ィエD2 diffusion continued 6 hrs after treatment.
5. For the long-storage of persimmon fruit, SAIJO, the optimal temperature is known to be 0℃. Therefore, the difference of temperature for the storage, artificial removal of astringency and shipping caused some problems. In this experiment, no apparent softening of fruit was not found at the temperature between 0 to 10℃. The fruit that underwent the temperature shift from 0 to 10℃ still kept its hardness for 10 days over 100 g at the top of fruit.
6. According to the experimental results described above, I studied the relationships between the conditions of gas, temperature, time and the degree of the astringency, fruit softening. Finally, at the optimal conditions i.e. gas : COィイD22ィエD2 : Air=6 : 4, temperature : 10℃, time : 12 hr, fruit astringency was removed completely in 2 days, and fruits kept their hardness for 10 days. Less