Notes on the Tannin Cells of Persimmon

Some cells of the floral organs of the sweet persimmon are transformed into tannin cells by changing suddenly their physiological activities and begin to accumulate tannin substances solved in the vacuoles. The astringent taste of young fruits is caused by the tannin substances in unhardened tannin cells. As the persimmon ripens the tannin cells increase in number and size until they harden to result in sweet taste of the fruit. During the hardening is progress the nucleus, cytosome and other components of the tannin cell become to coagulate. The membrane of the tannin cell shows no changes during the progress of the hardening.Among the various reagents which cause hardening absolute alcohol, aceton, aceto-aldehyde, aqueous solution of potassium bichromate, aqueous solution of chromic acid and alcohols of higher percentages produce the most natural state of the process. This seems to be very important in considering the fact that in the case of artificial reastringency ethyl-alcohol, aceto-aldehyde and aceton etc. are produced as the result of intramolecular respiration owing to insufficiency of oxygen.The tannin cells are hardened also by heating (ca. 100°C) and coaling (ca. 0°C).