within 48 hr after opening the gas containers ethanol
content increased by 10 times and acetaldehyde content
by about 4 times, respectively, compared to that of no
treated fruits. In the subsequent 24 to 48 hr, ethanol
content decreased and acetaldehyde content increased.
Such a divergency suggests that it is very interesting to
investigate the changes of biochemical reactions which
are concerned with the disappearance of astringency.
Some investigators observed that there was a large
quantity of accumulations of malate and citrate in the
persimmon fruit 9 •10 ): Therefore, the alterations of
organic acids were also investigated by silica gel column
chromatography'!') The results showed that each
content of malate and citrate per a treated fruit decreased
in 4.2 mg and increased in 12.8 mg. At 24 hr
after opening the containers, the treated fruits contained
about the same amounts of both acids as those of the
no treated ones.
It is obscure at present time to what extent these
fluctuations of several organic constitutes is concerned
with the de-astringency in the persimmon fruits. By
this new method for removing astringency in Kaki
fruits, however, the treated fruits do not accompany
with abnormal softening and this experimental system
may provide many significant evidences which are
concerned with the disappearance of astringency in
these fruits. We termed this new method "CTSD
method," Constant Temperature Short Duration
method.
The authors wish to thank Dr. Y. Momotani,
Department of Biology, Osaka Pref. University, for
their valuable advice.