抄録
Chlorophyll in persimmon leaves is rapidly decomposed into pheophytin by heating, causing the green color to disappear. In this work we studied the behavior of acid and tannin in persimmon leaves during heating, which is known to affect chlorophyll, and methods to prevent discoloration of persimmon leaves during heating.
The results obtained were as follows:
1) The acid and tainnin content of persimmon and maple leaves, whose chlorophyll was rapidly decomposed by heating, was higher than that of vegetable leaves whose chlorophyll is relatively resistant to heating.
2) Although acids and tannins in persimmon leaves were eluted during heating, their concentrations were still high at the early stage of heating when chlorophyll decomposition had proceeded. These results suggest that the contact of chlorophyll with acid and tannin, brought about by the rapid transformation through heating of the cellular membranes which separate the chlorophyll from the other two materials in untreated leaves, causes the rapid deterioration of chlorophyll in persimmon leaves.
3) When lyophilized persimmon leaves were dipped into water, acid and tannin were largely removed from the leaves. The chlorophyll of persimmon leaves after this treatment was remarkably resistant to heating. Furthermore, the green color of persimmon leaves dipped in a sodium hydrogencarbonate solution before heating was more resistant to heating.
