It is well-known that Japanese persimmons' astringency can be removed by means of the injection of alcohol solution. But the deta on its process has been made not so clear. This experiment was made to investigate the process of the removal of astringency by the alcohol injection method and to find out a physiological property of Japanese persuimmons. The variety employed in this experiment was "Hiratanenashi" and the dosage of alcohol into a fruit was less than 3 ml as absolute alcohol.
The results are summarized as follows :
1. The minimum dosage of alcohol to remove astringency was 0.5 ml as absolute alcohol and it was enough. Alcohol more than it did not removed astringency the easier. It needed five days at least to remove astringency by this method.
2. The injection of alcohol solution promoted softening of fruits. So, when astringency was removed the fruits had been softened and its market value had deteriorated.
3. The cause of the softening of fruits by the injection of alcohol solution was considered to be effect of enzyme that was activated by the injection of alcohol solution.