getting the good commodities without softening. Sato
and Kat03 ) obtained the evidence that it was necessary
to contain oxygen of several percent in the treating gas
loaded with carbon dioxide of more than 90 percent
from their experiments concerning to the effects of gas
compositions on the softening. Komeda et al. 4 ) also
reported that the gas composed not only of 60~ 80
percent carbon dioxide but of 2 ~ 3 percent oxygen
should be available for the removal of astringency in
the fruit. However, we did not measure accurately
the gas compositions in this experiments.
The changes in several components of the fruits
during this new treatment were examined. The fruits
were harvested on the 12th of October in 1974. Removal
of astringency was performed by carbon dioxide
at 20°C for 24 hr, following the 3 days storage in air
at 30°C and then the treated fruits were divided into
four parts of the same number. Each part of them was
used for determination of tannin, ethanol and acetaldehyde,
and organic acids, respectively. The results
in Fig. 1 showed the change of tannin content
which was determined by the micro-Lowenthal method,51
and the initial content of soluble tannin was
1492.1 mg per fruit. It is very interesting that Kakitannin
content does not decrease significantly within
the first 24 hr after the treatment but does decrease
promptly in the subsequent 24 to 48 hr. By these facts
it has been definitely shown that the biochemical processes
induced by carbon dioxide proceed without the
presence of the gas, and that it is able to remove
astringency in the persimmon fruits. Gazit and Adat06 )